CN104812731A - Method for producing formic acid - Google Patents

Method for producing formic acid Download PDF

Info

Publication number
CN104812731A
CN104812731A CN201380061951.3A CN201380061951A CN104812731A CN 104812731 A CN104812731 A CN 104812731A CN 201380061951 A CN201380061951 A CN 201380061951A CN 104812731 A CN104812731 A CN 104812731A
Authority
CN
China
Prior art keywords
methyl
tertiary amine
amine
formic acid
stream
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201380061951.3A
Other languages
Chinese (zh)
Inventor
D·M·弗莱斯
K-D·莫尔
M·舍费尔
D·施奈德
P·巴斯勒
S·里廷格
J·H·特莱斯
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of CN104812731A publication Critical patent/CN104812731A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/02—Preparation of carboxylic acids or their salts, halides or anhydrides from salts of carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/09—Preparation of carboxylic acids or their salts, halides or anhydrides from carboxylic acid esters or lactones
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation

Abstract

The invention relates to a method for obtaining formic acid by thermal separation of a stream containing formic acid and a tertiary amine (I), according to which method a liquid stream containing formic acid, methanol, water and tertiary amine (I) is produced in step (a) by bringing together methyl formate, water and tertiary amine (I), methanol is removed therefrom in step (b), and in step (c) formic acid is removed by distillation from the obtained liquid stream in a distillation device, wherein, when bringing together methyl formate, water and tertiary amine (l), methyl formate, water and optionally tertiary amine (I) are initially supplied in step (a1) in a molar ratio of 0 <= n(amine to a1) / n(methyl formate to a1) <= 0.1 and 70 to 100% of the possible hydrolysis equilibrium is adjusted, and subsequently in step (a2) tertiary amine (I) is supplied in a molar ratio of 0.1 <= n(amine to a2) / n(methyl formate to a1) <= 2 and the mixture is reacted.

Description

Produce the method for formic acid
The present invention relates to and a kind of comprise the stream of formic acid and tertiary amine (I) by thermal separation and obtain the method for formic acid, the boiling point that this tertiary amine (I) has under the pressure of 1013hPa abs than the boiling point height at least 5 DEG C of formic acid, wherein
The liquid stream comprising formic acid, methyl alcohol, water and tertiary amine (I) is produced by merging methyl-formiate, water and tertiary amine (I), the methyl alcohol be included in wherein of 10-100 % by weight is isolated from the liquid stream obtained by step (a), and
By distillation and take out formic acid from the liquid stream comprising formic acid, water and tertiary amine (I) obtained by step (b) under the pressure of the bottom temp of 100-300 DEG C and 30-3000hPa abs in distillation plant.
Formic acid is important and multifunctional product.Such as it is for acidifying in the production of animal-feed, as sanitas, as sterilizing agent, in textiles and leathers industry, is used as auxiliary agent, as the composite structure unit being used for aircraft and runway deicing and being also used as in chemical industry with the mixture of its salt.
The most extensive method preparing formic acid is at present hydrolysis methyl-formiate, and latter case is as obtained by methyl alcohol and carbon monoxide.Concentrate subsequently by being hydrolyzed the water-containing formic acid obtained, such as, use extraction auxiliary agent as dialkylformamide (DE 25 45 658 A1).
In addition, it is also known for obtaining formic acid by the thermal dissociation of the compound of formic acid and tertiary nitrogen alkali.These compounds are generally the acidic ammonium formate of tertiary nitrogen alkali, and wherein formic acid has been reacted to the workshop section exceeded with the classical salify of tertiary nitrogen alkali, are formed by the stable addition compound of hydrogen bond bridge joint.The addition compound of formic acid and tertiary nitrogen alkali can by merging tertiary nitrogen alkali and formic acid source and formed.Therefore, such as WO 2006/021,411 disclose usual pass through (i) makes this tertiary nitrogen alkali and formic acid direct reaction, (ii) under this tertiary nitrogen alkali exists, be hydrogenated to formic acid by transition metal-catalyzed for carbonic acid gas, (iii) methyl-formiate and water is reacted also extract gained formic acid by this tertiary nitrogen alkali subsequently and (iv) makes methyl-formiate and water react under this tertiary nitrogen alkali exists and prepare such addition compound.
The general advantage using the addition compound of formic acid and tertiary nitrogen alkali to obtain formic acid is that addition compound is combined with formic acid and by the medium being formed formic acid wherein by chemosynthesis first enough by force, formic acid is taken out by dilute formic acid solution such as, in reaction medium or such as, and allow thus more easily to go out formic acid with its addition compound isolated in form, but enough weak again can be discharged from addition compound by thermal dissociation to formic acid subsequently, thus obtain it with free form that is concentrated and that purify.
EP 0 001 432 A discloses a kind of by tertiary amine, and especially alkyl imidazole exists lower hydrolysis methyl-formiate and obtains the method for formic acid to form the addition compound of formic acid and this tertiary amine.From the gained hydrolysed mix removing low-boiling-point substance methyl-formiate and the methyl alcohol that comprise unreacted methyl-formiate, water, methyl alcohol, addition compound and tertiary amine in the first distillation tower.Bottoms dehydration will be remained in the second tower.Then the bottoms of dehydration still comprising adduct and tertiary amine from the second tower is fed in the 3rd tower also wherein by addition compound thermal dissociation formic acid and tertiary amine.The formic acid of release takes out as overhead product.Tertiary amine is collected in the liquid phase and is recycled in hydrolysis.
DE 34 28 319 A discloses a kind of method being obtained formic acid by hydrolysis methyl-formiate.From the gained hydrolysed mix removing low-boiling-point substance methyl-formiate and the methyl alcohol that comprise unreacted methyl-formiate, water, methyl alcohol and formic acid in the first distillation tower.The water-containing formic acid obtained in bottom uses higher amine subsequently, especially comparatively long-chain hydrophobic C 6-C 14trialkylamine is at extra hydrophobic solvent, and especially aliphatic, alicyclic or aromatic hydrocarbon exists lower extraction, and changes into the moisture addition compound of formic acid and this amine thus.In second column, this is dewatered.Then the adduct of dehydration that obtains in bottom to be fed in the 3rd distillation tower and thermal dissociation wherein.This hydrophobic solvent is present in from both the overhead of this tower and bottoms.This gaseous overhead stream mainly comprise together with this hydrophobic solvent discharge formic acid.This stream liquefies within the condenser again.This causes forming two-phase, i.e. polarity formic acid phase and hydrophobic solvent phase.Formic acid is discharged as product, and solvent phase returns in tower as reflux.Owing to there is hydrophobic solvent, dissociating completely of this adducts can be realized, and this there is no formic acid to decompose lower generation according to being taught in of announcing first of this DE.(substantially) does not comprise hydrophobic amine and hydrophobic solvent containing the bottoms of formic acid.This is recycled in extraction workshop section.
WO 2006/021,411 describes a kind of addition compound (quaternary ammonium formate) by thermal dissociation formic acid and tertiary amine and obtains the method for formic acid, and wherein the boiling point of tertiary amine is 105-175 DEG C.Alkyl pyridine is mentioned as preferred tertiary amine.This specific boiling range of tertiary amine improves the colour stability of gained formic acid.Stand-by addition compound can be obtained by tertiary amine and formic acid source usually.Advantageously first from the output removing volatile component synthesized from adducts, then sent to thermal dissociation.Thermal dissociation carries out in a distillation column as routine.The formic acid of release takes out as overhead product.The tertiary amine that still can comprise residual formic acid is collected in the liquid phase and can be recycled in formic acid source.
EP 0 563 831 A reports the addition compound (quaternary ammonium formate) of a kind of thermal dissociation formic acid and tertiary amine to obtain improving one's methods of formic acid.Stand-by addition compound can be obtained by tertiary amine and formic acid source usually.Advantageously first from the output removing volatile component from this synthesis, then sent to distillation tower and carried out thermal dissociation.The thermal dissociation of this addition compound is carried out in this improvement under being substantially included in the secondary methane amide existence of the colour stability improving gained formic acid.The formic acid of release takes out as overhead product.Tertiary amine and secondary methane amide are collected in the liquid phase and can be recycled in formic acid source.
WO 2012/000, 964 teach and a kind ofly comprise the stream of formic acid and tertiary amine by thermal separation and obtain the method for formic acid, wherein tertiary amine and formic acid source are merged the liquid stream producing and comprise formic acid and tertiary amine with the mol ratio of 0.5-5, isolate being contained in secondary component wherein and taking out formic acid by distilling under the pressure of the bottom temp of 100-300 DEG C and 30-3000hPa in distillation plant from gained liquid stream of 10-100 % by weight, and the bottom output from distillation plant is separated into two liquid phases, wherein upper phase is rich in tertiary amine and is recycled in formic acid source, and lower floor's liquid phase is rich in formic acid and be recycled in the removing of secondary component and/or be recycled in distillation plant.
EP application 11 194 619.0 teaches and a kind ofly comprises the stream of formic acid and tertiary amine by thermal separation and obtain improving one's methods of formic acid, wherein produce by merging tertiary amine and formic acid source in the presence of water the liquid stream comprising formic acid, tertiary amine and water, except anhydrate and tertiary amine organic degradation product and in distillation plant by gained liquid stream distill formic acid, wherein the isolated stream comprising the organic degradation product of water and tertiary amine is separated into two liquid phases, the lower floor's liquid phase comprising water is also recycled in formic acid source by removing upper phase.Method described in EP application 11 194 619.0 allows various volatile byproducts to remove with the relative simple of degraded product of tertiary amine and discharge.
EP application 11 194 607.5 teaches and a kind ofly comprises the stream of formic acid and tertiary amine by thermal separation and obtain improving one's methods of formic acid, wherein produce by merging tertiary amine and formic acid source the liquid stream comprising formic acid and tertiary amine, isolate the secondary component be contained in wherein, steam except formic acid by gained liquid stream in distillation plant, bottom output from distillation plant is separated into two liquid phases, upper phase to be recycled in formic acid source and lower floor's liquid phase to be recycled in the removing of secondary component and/or to be recycled in this distillation plant, wherein from upper phase, isolate low-boiling-point substance and this depleted stream of recirculation by distillation.Method described in EP application 11 194 607.5 allows various volatile byproducts to remove with the relative simple of degraded product of tertiary amine and discharge.
The object of the invention is to find a kind ofly comprise the stream of formic acid and tertiary amine by thermal separation and obtain improving one's methods of formic acid, the method is better than prior art and can obtains formic acid with high yield and high density.This improve one's methods especially also should within the long operating time steady running and with constant high purity produce formic acid.The method naturally should be able to be very simple and implement with unusual less energy-consumption.
We have shockingly found a kind ofly comprise the stream of formic acid and tertiary amine (I) by thermal separation and obtain the method for formic acid, the boiling point that this tertiary amine (I) has under the pressure of 1013hPa abs is than the boiling point height at least 5 DEG C of formic acid, wherein by merging methyl-formiate, water and tertiary amine (I) are produced and are comprised formic acid, methyl alcohol, the liquid stream of water and tertiary amine (I) also isolates the methyl alcohol be contained in wherein of 10-100 % by weight from the liquid stream obtained by step (a), and by distillation and from the formic acid that comprises obtained by step (b) under the pressure of the bottom temp of 100-300 DEG C and 30-3000hPa abs in distillation plant, the liquid stream of water and tertiary amine (I) takes out formic acid, wherein when step a) in merge methyl-formiate, when water and tertiary amine (I), methyl-formiate is introduced in step (a1), water and optional tertiary amine (I), the tertiary amine (I) " n (introducing the amine of a1) " wherein optionally introduced in step (a1) makes 0≤n (introducing the amine of a1)/n (introducing the methyl-formiate of a1)≤0.1 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and at the temperature of 50-200 DEG C, set the hydrolysising balance possible under prevailing conditions of 70-100%, and then in step (a2), tertiary amine (I) is introduced in the stream obtained in step (a1), the tertiary amine (I) " n (introducing the amine of a2) " be wherein introduced in step (a2) in the stream obtained in step (a1) makes 0.1≤n (introducing the amine of a2)/n (introducing the methyl-formiate of a1)≤2 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and what make gained mixture react to obtain at the temperature of 50-200 DEG C to mention under (a) comprises formic acid, methyl alcohol, the liquid stream of water and tertiary amine (I), the total tertiary amine (I) " n (introducing the amine of a) " wherein introduced in step (a) is at least 0.1 with the mol ratio of the total methyl-formiate " n (introducing the methyl-formiate of a) " introduced in step (a).
The boiling point had under 1013hPa abs for the tertiary amine (I) in the step (a) of the inventive method is than the boiling point height at least 5 DEG C of formic acid.The boiling point that stand-by tertiary amine (I) preferably has is than the boiling point height at least 10 DEG C of formic acid, particularly preferably high at least 50 DEG C, very particularly preferably high at least 100 DEG C.In the preferred replacement embodiment of the inventive method, the absolute boiling point that stand-by tertiary amine (I) has under the pressure of 1013hPa abs is at least 111 DEG C, in replacement embodiment very preferably, be at least 151 DEG C, in most preferred replacement embodiment, be at least 201 DEG C.Restriction with regard to boiling point higher limit is also unnecessary, because the very low-vapor pressure of tertiary amine (I) is favourable to the inventive method substantially.Tertiary amine (I) boiling point under the pressure being extrapolated to 1013hPa abs by vacuum optionally through currently known methods is usually less than 500 DEG C.
The methyl-formiate be ready to use in the inventive method is introduced usually in liquid form.Stand-by methyl-formiate can from each provenance.The source of current industrial most important synthesis methyl-formiate is the carbonylation of methyl alcohol.In addition, such as can also will in this hydrolysis not yet reaction and in later step isolated recirculation methyl-formiate be used in the inventive method.
The water of substitute in the inventive method is introduced usually equally in liquid form.In order to avoid this equipment salting up gradually, preferably use softening water or deionized water.
According to the present invention, shockingly find tertiary amine (I) to tend to methylate under methyl-formiate exists and form corresponding carboxylic acid methyl ammonium and this effect is even being produced in formic acid under the reaction conditions of prior art routine, have negative impact by being hydrolyzed methyl-formiate under existing at tertiary amine, especially in the relative long running time course of several weeks or several months.At tertiary amine (I), there are 3 identical radicals R, such as C 5-C 8when alkyl, described methylation reaction is such as follows, and wherein Me is methyl:
The carboxylic acid methyl ammonium formed can dissociate again again, wherein in the reaction of the reversion for reactional equation (A), again must return initial amine NR 3and in reaction shown in reactional equation (B), form tertiary amine and the alkyl formate with methyl.
In addition, have been found that the mode that the methylic tertiary amine of bag formed according to reactional equation (B) tends to be similar to reactional equation (A) and (B) is methylated by methyl-formiate further and dissociates in the context of the present invention.In this way can by the tertiary amine continuous solution that uses at first from until Trimethylamine 99.
Thus via the described organic degradation product being obtained by reacting tertiary amine (I).For the purpose of the present invention, term " the organic degradation product of tertiary amine (I) " typically refers to the compound formed by the chemical transformation of tertiary amine (I), wherein initial exist bond rupture, again formed nitrogen-carbon bond or with the group of nitrogen bonding and the group generation chemical transformation of any elimination.
The organic degradation product of tertiary amine (I) may cause the formic acid that will obtain according to step (c) contaminated.In addition, boiling point to tend to be gathered in step (c) in distillation plant used at formic acid boiling point to the organic degradation product of the tertiary amine (I) in tertiary amine (I) boiling spread and increases the energy consumption of this distillation plant thus.The organic degradation product not assembling the tertiary amine (I) reducing its purity in formic acid to be separated must be discharged in other positions of the method, to prevent not controlled gathering.
The targets that EP above-mentioned application 11 194 619.0 relates to the specific organic degradation product of tertiary amine (I) are really discharged, but be only can together with water in step (b) under leading processing condition isolated those.Because the separation according to the instruction of EP application 11 194 619.0 is carried out preferably by distillation, this also preferably only relates to can by gas phase distillation and condensation subsequently by remaining mass flow those degraded products isolated.
The target that EP application 11 194 607.5 also illustrates the specific organic degradation product of tertiary amine (I) is discharged.When this discharge also by isolating degraded product via the distillation of gas phase and condensation subsequently, but from applying for 11 194 619.0 different streams from EP and in the position different with it.
Except formic acid to be obtained possibility is contaminated and except the organic degradation product discharge problem of tertiary amine (I), the degraded of tertiary amine (I) also causes the loss of tertiary amine (I) naturally, result must introduce this material of further amount continuously.Therefore, in order to prevent this problem, the more small loss of tertiary amine (I) is favourable economically.
In addition, also shockingly find that the carboxylic acid methyl quaternary ammonium that such as formed by reactional equation (A) catalysis formic acid under the common process condition of methyl formate hydrolysis and aftertreatment reaction mixture subsequently resolves into carbonic acid gas and hydrogen in the context of the present invention.
According to the present invention, now shockingly find tertiary amine (I) degraded formed tertiary amine (I) organic degradation product and especially tertiary amine (I) methylated by methyl-formiate and form carboxylic acid methyl ammonium (as an example as shown in reactional equation (A)) and can significantly reduce, if when merge in the step (a) methyl-formiate, water and tertiary amine (I) time
(a1) in step (a1), introduce methyl-formiate, water and optional tertiary amine (I), the tertiary amine (I) " n (introducing the amine of a1) " wherein optionally introduced in step (a1) makes 0≤n (introducing the amine of a1)/n (introducing the methyl-formiate of a1)≤0.1 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and at the temperature of 50-200 DEG C, set the hydrolysising balance possible under prevailing conditions of 70-100%, and
(a2) then in step (a2), tertiary amine (I) is introduced in the stream obtained in step (a1), the tertiary amine (I) " n (introducing the amine of a2) " be wherein introduced in step (a2) in the stream obtained in step (a1) makes 0.1≤n (introducing the amine of a2)/n (introducing the methyl-formiate of a1)≤2 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and what make gained mixture react to obtain at the temperature of 50-200 DEG C to mention under (a) comprises formic acid, methyl alcohol, the liquid stream of water and tertiary amine (I),
The total tertiary amine (I) " n (introducing the amine of a) " wherein introduced in step (a) is at least 0.1 with the mol ratio of the total methyl-formiate " n (introducing the methyl-formiate of a) " introduced in step (a).
Tertiary amine (I) the formic acid ammonium methyl that methylates effectively can be reduced by the invention described above measure, this not only causes carboxylic acid methyl ammonium concentration in the method to reduce, and cause in following reaction, such as, reduce in the following reaction represented by reactional equation (B).
As the conversion unit that methyl-formiate, water and tertiary amine (I) react according to the present invention, using priciple can be applicable to such all devices reacted.It is known that these are generally those skilled in the art.Such as, they especially comprise stirred vessel, stirred vessel cascade, flow reactor, tubular reactor, microreactor and stop container, are with or without directly cooling in each case and are with or without other internals.Two steps (a1) and (a2) can depend on that embodiment is carried out in single reaction vessel or in two or more reactors be connected in series.If two steps (a1) and (a2) carry out in single reaction vessel, then usually advantageously offset back mixing.When flow reactor, because flow exists enough low back mixing usually with the ratio of internal cross section, thus other internals can not be required here.When tubular reactor, orifice plate or zigzag path such as effectively can prevent back mixing.
The ratio that can be used in step (a1) in the methods of the invention can be used for the volume reacted in the volume that reacts and step (a2) is generally 0.01-10.For the purpose of the present invention, term volume relates to actual void volume.Therefore, such as the volume of possibility internals not can be regarded as a part for this actual void volume.Above-mentioned volume ratio is preferably 0.05-5, particularly preferably 0.08-2, very particularly preferably 0.1-1, especially 0.15-0.9.
Methyl-formiate in (a1) to be introduced in step and (a2), water and tertiary amine (I) in each case can from one or more sources.Possible source is such as introduce fresh feed by the outside of the method or introduce recycle stream by the method itself.The independent feed steam of step (a1) and (a2) such as can separately be introduced, in advance part mixing or mix completely.
Be described in more detail step (a1) below.
In the methods of the invention, tertiary amine (I) " n (introducing the amine of a1) " in optional introducing step (a1) makes 0≤n (introducing the amine of a1)/n (introducing the methyl-formiate of a1)≤0.1 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and wherein this mathematical formula corresponds to the scope of described mol ratio is 0-0.1.The mol ratio of n (introducing the amine of a1)/n (introducing the methyl-formiate of a1) is preferably 0-0.05, particularly preferably 0-0.02, very particularly preferably 0-0.01.In step (a1), the optional tertiary amine (I) introduced is less with the mol ratio of the methyl-formiate introduced in step (a1), and under condition identical in other respects, the formation not wishing organic degraded product of tertiary amine (I) is usually less.Therefore, even can omit and introduce in step (a1) by tertiary amine (I), this mol ratio corresponding to n (introducing the amine of a1)/n (introducing the methyl-formiate of a1) is 0 and is also represented by " optionally " in the description wording of step (a1).
The water yield advantageously set in (a1) to be introduced in step in the methods of the invention makes first not too greatly diluted reaction mixture, otherwise further aftertreatment can be made more difficult due to high dilution and large volume stream, secondly the enough high conversion to methyl-formiate also occurs.Typically, the water calculated by the water introduced in step (a1) " n (introducing the water of a1) " and the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1) and the mol ratio of methyl-formiate are that 0.1-10 is seemingly favourable.Described mol ratio preferably >=0.2, particularly preferably >=0.3, and preferably≤8, particularly preferably≤6.
In the step (a1) of the inventive method, the possible hydrolysising balance under prevailing conditions of setting 70-100%.If the parameter affecting this hydrolysising balance such as also has the leading concentration of tertiary amine (I) for formic acid, methyl alcohol, water, methyl-formiate and the words introduced in step (a1) and naturally also has temperature and leading pressure.For the purpose of the present invention, this hydrolysising balance is the zero dimension K value according to equation (D):
K=[c (formic acid) c (methyl alcohol)]/[c (methyl-formiate) c (water)] (D),
Wherein c (...) is in the leading concentration of mol/l in each case.Equation (D) no matter in step (a1), whether there is tertiary amine (I) and no matter in a free form whether described 4 kinds of components, ionic species is (such as formate anion HCOO -instead of formic acid HCOOH) or exist all applicable with form complexed.Therefore, such as " c (formic acid) " also comprises the formate anion HCOO of any existence -concentration.Described percentage ratio now corresponds to the ratio of maximum K value possible in theory under prevailing conditions.
>=75% is preferably set, particularly preferably >=80%, very particularly preferably >=85%, the hydrolysising balance possible under prevailing conditions of especially >=90% in step (a1).
Setting hydrolysising balance carrying out advantageous by setting adequate residence time at a certain temperature under certainty ratio at material quantity in step (a1).For the said temperature scope of 50-200 DEG C, have been found that 0.01-5 hour, preferred 0.02-2 hour, particularly preferably the mean residence time of 0.05-1 hour is favourable.Temperature is higher, and the setting of hydrolysising balance usually can be faster and mean residence time therefore also can be shorter.
Hydrolysis in step (a1), preferably at >=70 DEG C, particularly preferably >=80 DEG C, very particularly preferably >=90 DEG C, and preferably≤150 DEG C, particularly preferably≤140 DEG C, is carried out at the temperature of very particularly preferably≤130 DEG C.Hydrolysis in step (a1) is carried out usually at the temperature of 70-150 DEG C.Have been found that the formation not wishing organic degraded product of tertiary amine (I) increases along with temperature improves usually and therefore lesser temps is favourable thus.In addition, erosion rate improves with temperature, and thus lesser temps is also favourable viewed from this angle.On the other hand, speed of reaction also reduces along with temperature and reduces, and the residence time thus in very low temperatures required by given conversion significantly increases and therefore requires reactor large wastefully.It is possible that will find compromise between these two kinds of effects, this is also reflected in said temperature scope.
The liquid stream that will be obtained by step (a1) is subsequently introduced in step (a2).Therefore, step (a2) is hereafter described in more detail.
Then in step (a2), tertiary amine (I) is introduced in the stream obtained in step (a1).In the methods of the invention, the tertiary amine (I) " n (introducing the amine of a2) " be introduced in step (a2) in the stream obtained in step (a1) makes 0≤n (introducing the amine of a2)/n (introducing the methyl-formiate of a1)≤2 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and wherein this mathematical formula corresponds to the scope of above-mentioned mol ratio is 0.1-2.Mol ratio n (introducing the amine of a2)/n (introducing the methyl-formiate of a1) preferably >=0.13, particularly preferably >=0.15, very particularly preferably >=0.2, and preferably≤1.9, particularly preferably≤1.8, very particularly preferably≤1.7, especially≤1.5.
In the step (a2) of the inventive method, except Already in from except the water in the stream of step (a1) and methyl-formiate, further water and methyl-formiate can be introduced in principle.
If introduce further water, then set its amount ideally, make first not too greatly diluted reaction mixture, otherwise further aftertreatment can be made more difficult due to high dilution and large volume stream, and secondly the advantageous effects of any type causes the further hydrolysis of the methyl-formiate existed or is hydrolyzed further at another some place in further method.Favourable effect can be such as this balance to the favourable aftertreatment of the skew of formic acid direction or reaction mixture.Typically, it is possible that find the balance between merits and demerits.
This is equally applicable to add further methyl-formiate.
Hydrolysis in step (a2) is carried out at the temperature of 50-200 DEG C.It is preferably at >=80 DEG C, particularly preferably >=90 DEG C, and preferably≤170 DEG C, carry out at the temperature of particularly preferably≤150 DEG C.Hydrolysis in step (a2) is carried out usually at the temperature of 70-150 DEG C.In step (a2), the formation not wishing organic degraded product of tertiary amine (I) and corrosion usually also increase along with temperature improves and lesser temps is favourable thus.On the other hand, speed of reaction also reduces with temperature and reduces, and the residence time thus in very low temperatures required by specific conversion significantly increases and therefore requires reactor large wastefully.Therefore in step (a2) also it is possible that compromise will be found between these two kinds of effects, this is also reflected in said temperature scope.Therefore, the temperature in step (a1) and step (a2) can be different.The heat of releasing in the reaction at a step Nei Wenduyin and different or initiatively affect temperature by heating or cool be feasible and possible.
In the step (a2) of the inventive method, preferably set 50-100%, particularly preferably >=60%, very particularly preferably >=70%, the hydrolysising balance possible under prevailing conditions of especially >=80%.As mentioned above, this hydrolysising balance such as by formic acid, methyl alcohol, water, methyl-formiate and also have tertiary amine (I)-because its in conjunction with formic acid-leading concentration and in addition temperature and leading pressure influence naturally.Setting hydrolysising balance carrying out advantageous by the adequate residence time set at a certain temperature under certainty ratio at material quantity in step (a2).For the said temperature scope of 50-200 DEG C, have been found that 0.01-5 hour, preferred 0.2-3 hour, particularly preferably the mean residence time of 0.3-2 hour is favourable.Temperature is higher, and the setting of hydrolysising balance usually also carries out sooner and mean residence time correspondingly also can be shorter.
In addition, the total tertiary amine (I) " n (introducing the amine of a) " introduced in the methods of the invention in step (a) is generally at least 0.1 with the mol ratio of the total methyl-formiate " n (introducing the methyl-formiate of a) " introduced in step (a).Here the n amine of a (introduce) corresponds to the summation all introduced all tertiary amines (I) in step (a) and measure, i.e. the summation of n (introducing the amine of a1) and n (amine of introducing a2) in the method being divided into step (a1) and (a2).Correspondingly, n (introducing the methyl-formiate of a) corresponds to the summation all introducing all methyl-formiate amounts in step (a).In the method being divided into step (a1) and (a2), therefore this correspond to the summation of n (introducing the methyl-formiate of a1) and n (introducing the methyl-formiate of a2), wherein " n (introducing the methyl-formiate of a2) " methyl-formiate amount for optionally introducing except the stream obtained in step (a1) in step (a2).The mol ratio of the n amine of a (introduce)/n (introducing the methyl-formiate of a) is preferably at least 0.13, and particularly preferably at least 0.15, very particularly preferably at least 0.2.
The upper limit of the mol ratio n amine of a (introduce)/n (introducing the methyl-formiate of a) finally by mol ratio n (introducing the amine of a1)/n (introducing the methyl-formiate of a1) and n (introducing the amine of a2)/n (introducing the methyl-formiate of a1) the decision of upper limit sum and be therefore unnecessary as concrete described number.As the n amine of a1 (introduce)/n (introducing the methyl-formiate of a1)≤0.1 and n (introducing the amine of a2)/n (introducing the methyl-formiate of a1)≤2 time, the upper limit therefore≤2.1 of n (introducing the amine of a)/n (introducing the methyl-formiate of a).
The total water " n (introducing the water of a) " introduced in step (a) is provided divided by n (introducing the methyl-formiate of a1) and n (introducing the methyl-formiate of a2) sum by n (introducing the water of a1) and n (introducing the water of a2) sum with the mol ratio of the total methyl-formiate " n (introducing the methyl-formiate of a) " introduced in step (a)." n (introducing the water of a2) " water yield for optionally introducing except the stream obtained in step (a1) in step (a2).Typically, the mol ratio of n (introducing the water of a)/n (introducing the methyl-formiate of a) is that 0.1-10 is seemingly favourable.Above-mentioned mol ratio preferably >=0.2, particularly preferably >=0.3, and preferably≤8, particularly preferably≤6.
Above-mentioned measure of the present invention makes it possible to the formation of the organic degradation product significantly reducing tertiary amine (I).
As above in detail as described in, methyl-formiate, water and tertiary amine (I) being incorporated in two steps (a1) and (a2) in the step (a) of the inventive method is carried out.These two steps can be divided into again other steps (cascade).These are referred to as sub-step for the purpose of the present invention and are specifically called step (a1-i), (a1-ii), (a1-iii) etc., or (a2-i), (a2-ii), (a2-iii) etc.According to term of the present invention, step (a1) and (a2) always comprise Overall Steps (a1) or (a2), whether be divided into sub-step with these, whether can be divided into sub-step or whether be not divided into maybe can not be divided into sub-step have nothing to do.
Sub-step makes it possible to control reaction conditions even more subtly.Specifically, independent component methyl-formiate, tertiary amine (I) and water can be introduced in a hierarchical manner in single step (a1) and (a2).Group component in (a1) to be introduced in step and (a2), such as n (introducing the amine of a1) or n (introducing the methyl-formiate of a1), relate to any single reinforced summation in corresponding steps naturally in each case.Equally, such as treat that the hydrolysising balance value of setting in step (a1) relates to the stream existed at the end of step (a1).
In addition, having been found that in the context of the present invention tertiary amine (I) classification to be introduced in step (a2) with sub-step form causes the organic degradation product of tertiary amine (I) to reduce further.In a preferred embodiment of the present methods, tertiary amine (I) is therefore introduced in step (a2) in a hierarchical manner.For the purpose of the present invention, classification is introduced is along response path successively or continuous charging.In the context of the inventive method, response path is in corresponding steps, is the reaction process in step (a2) in the present case.When reinforced successively, the tertiary amine (I) treating to be introduced in step (a2) in the stream obtained in step (a1) is measured and is divided into multiple separate charging along response path.Therefore each separate charging may cause reacting further successively of existing mixture.In the limiting case, can also carry out the reinforced of the very low amount tertiary amine (I) of unlimited number of times, this is mathematically equal to along response path continuous charging.
Be preferably as follows the inventive method, wherein in step (a2), tertiary amine (I) is introduced 2-100 sub-steps, particularly preferably 2-10 sub-steps, very particularly preferably 2-5 sub-steps, especially in 2-3 sub-steps, particularly 2 sub-steps.From reducing further, the formation of the organic degradation product of tertiary amine (I) is optimized better by meaning in principle, in step (a2), tertiary amine (I) is reinforced more fine graded.On the other hand, the expenditure of the two with regard to instrumentation of making peace with regard to equipment also increases along with the number increase of sub-step usually.Therefore in practice it is possible that balancing benefits and shortcoming.
If in the methods of the invention tertiary amine (I) is introduced in step (a2) in a hierarchical manner, then usually advantageously introduce in a sub-steps with regard to reducing the formation of the organic degradation product of tertiary amine (I) further and be no more than 90% of stream total amount n (introducing the amine of a2).Then the tertiary amine (I) of residual content is distributed in other sub-steps in step (a2) or step.Preferably introduce in a sub-steps and be no more than 80% of stream total amount n (introducing the amine of a2), be particularly preferably no more than 70%, be very particularly preferably no more than 60%, especially no more than 50%.
The expenditure of first making peace with regard to equipment in instrumentation wherein keeps very low by tertiary amine (I) classification being introduced in step (a2), but secondly significantly reduce in the preferred version of the organic degradation product of tertiary amine (I) further, the 10-90% of stream total amount n (introducing the amine of a2) is introduced in a sub-steps of step (a2), particularly preferably 20-80%, very particularly preferably 30-70%, and in sub-step subsequently, introduce the 10-90% of stream total amount n (introducing the amine of a2), particularly preferably 20-80%, very particularly preferably 30-70%, before sub-step subsequently, wherein set the hydrolysising balance possible under prevailing conditions of 50-100%.This operator scheme is first usual to be remained on the formation effectively reducing the organic degradation product of tertiary amine (I) further enough low but then to the sufficiently high specified amount n of remarkable hydrolysis further (introducing the amine of a2) causing methyl-formiate by the concrete concentration accounting for leading tertiary amine (I) at corresponding feed point based on methyl-formiate concentration.In order to farthest utilize this effect, before sub-step subsequently, set 50-100%, preferably >=60%, particularly preferably >=70%, very particularly preferably >=80%, the hydrolysising balance possible under prevailing conditions of especially >=90%.
Above with regard to conversion unit illustration be also applicable in principle single component in step (a1) and/or (a2) one or both of classification feed in raw material.Therefore, depend on embodiment, classification also can be carried out in single reaction vessel or in two or more in succession reactor.Correspondingly, usually back mixing is offset when this reaction is carried out in single reaction vessel also advantageously.About flow reactor and tubular reactor illustration are suitable for similarly.When classification, preferably use the tubular reactor with orifice plate in the methods of the invention.
In the sequence of independent reaction zone, also maybe advantageously insert stacking area, namely wherein reaction mixture reacts further if having time and does not directly add the region of other components in this zone on balance direction.Therefore, such as have been found that and usefully step (a1) is divided into two sub-steps, wherein methyl-formiate, water and optional tertiary amine (I) to be introduced in the first sub-step (a1-i) and partial hydrolysis occurs wherein, and give this mixture subsequently and in the second sub-step (a1-ii), reach balance with the further time and do not add other components.
In particularly preferred scheme, these two comprise and may the step (a1) of sub-step and (a2) carry out in the single pipe reactor providing orifice plate.
When tertiary amine (I) classification being introduced in step (a2), the volume ratio of independent sub-step especially depends on the amine amount introduced in each case, the required residence time, required methyl-formiate transformation efficiency and technically possible mixing time.Usual trial is by volume ratio and amine ratio match.But the volume distributed median had nothing to do with amine ratio is also possible and is favourable even in some cases.
Because the reaction of methyl-formiate and water heat release under tertiary amine (I) exists is carried out, therefore reaction mixture is heated.But, in order to make controlled reaction become possibility, advantageously regulate the temperature distribution in these two steps (a1) and (a2) or in its any sub-step.The measure possible for this object be such as directly the corresponding one or more inflow stream of cooling or or directly cool in reactor or respective section, such as by interchanger as cooling worm.Further possibility is such as introduced in step (a2) or its sub-step by the tertiary amine with suitable temp (I).The temperature of tertiary amine (I) such as can control by being mixed into the stream of colder (if possible precooling) or warmer (if possible preheating) according to traditional regulation method target.
The organic degradation production concentration that the present invention is tertiary amine in hydrolysis output relative to the advantage of prior art (not classification) significantly reduces.Therefore, the concentration of organic degradation product in hydrolysis output of this amine can reduce 10-100%.The preferred >20% of this reduction, particularly preferably >30%, very particularly preferably >50%.In this hydrolysis output, the organic degradation product amount of this amine reduces usually up to 99%, advantageously up to 99.5%, more advantageously up to 99.9% and under the best circumstances even up to 100%.
Merge in the step (a) methyl-formiate, water and tertiary amine (I) time the formic acid that usually has of the liquid stream produced and the mol ratio of tertiary amine (I) be 0.1-10.This mol ratio preferably >=0.5, particularly preferably >=1, and also preferably≤5, particularly preferably≤3.Described mol ratio based on total liquid stream, with whether as single-phase or multiple exist mutually irrelevant.
It is 1-99 % by weight that the formic acid that the liquid stream comprising formic acid and tertiary amine (I) produced in the step (a) has usually adds tertiary amine (I) concentration based on the total amount of this stream.The formic acid that described stream preferably has adds tertiary amine (I) concentration >=5 % by weight, particularly preferably >=15 % by weight.Even when for formic acid further purification be separated formic acid in the liquid stream that needs to produce in the step (a) add the concentration of tertiary amine (I) high especially time, guarantee that the expenditure with regard to equipment and process engineering required by these high densitys in step (a) also increases.For this reason, above-mentioned concentration in the methods of the invention advantageously≤90 % by weight.
The methyl alcohol be present in the liquid stream obtained by step (a) of 10-100 % by weight is separated by this liquid stream.Concentration in the liquid stream that methyl alcohol is produced in the step (a) is hereafter also referred to as " c methyl alcohol(stream from step (a)) ".The poor liquid stream containing methyl alcohol is corresponding to the stream fed according to step (c) in distillation plant.This concentration is hereafter also referred to as " c methyl alcohol(introducing the feed steam of step (c)) ".Therefore, the above-mentioned removing of methyl alcohol is based on following business:
Preferably isolate in step (b) >=20 % by weight, the methyl alcohol of particularly preferably >=30 % by weight.Usually isolate≤99.9 % by weight, the methyl alcohol of advantageously≤99.99 % by weight.
The mode isolating methyl alcohol is unimportant to the inventive method.Therefore, the method conventional and known for separation of liquid mixtures can such as be used.Can be first referred and be preferred by fractionation by distillation.Thus, separation of liquid mixtures in distillation plant.
In addition to methanol, unreacted methyl-formiate and also have other secondary components be naturally also present in the stream from step (a).Here term secondary component typically refers to all components in the liquid stream being contained in and obtaining in step (a) and neither formic acid neither tertiary amine (I).The example that can mention be water, methyl alcohol, methyl-formiate, the possible organic degradation product of tertiary amine (I), the rare gas element of dissolving and also have other components.
Usually advantageously also isolate other secondary components from the stream from step (a) in addition to methanol, especially methyl-formiate, also have water.In order to be separated other secondary components, usually the routine for separation of liquid mixtures can also be used and known method.Can mention by fractionation by distillation equally especially, wherein depend on that the position of boiling point can also carry out a part for this separation together in distillation plant.Therefore, such as methyl alcohol and other lower boiling secondary components such as methyl-formiate can be separated at top or as side-draw stream.But, it will also be appreciated that and isolate high boiling point secondary component in bottom and as side stream or even isolate the mixture comprising formic acid and tertiary amine (I) as overhead product.Except passing through fractionation by distillation, film, absorption and sorption, crystallization, precipitation, filtration, sedimentation or extracting process are also possible.The combination of multiple separation method is also possible.
Nature also can also combine multiple based on the separating step of different methods.The design of one or more separating step can use routine techniques knowledge to carry out.
By the position that distillation for removing methanol and the Chief amongst of the order of other secondary components are boiling points.Therefore, particularly advantageously first methyl-formiate is isolated at the first distillation plant top.This preferably can be recycled in step (a) subsequently, and formic acid can significantly improve thus based on the productive rate of methyl-formiate used.Methyl alcohol advantageously takes out from identical distillation plant as side-draw stream.But, methyl alcohol can also be isolated in separation distillation plant as replacement.Separated methyl alcohol such as can be used further in the synthesis of methyl-formiate.In distillation plant subsequently, water with can by distillation together with water any other secondary component isolated can advantageously remove via top subsequently.Isolated water can also be recycled in step (a).Because a small amount of secondary component is still included in isolated water, this recirculation avoids the special disposal of isolated water.Except to anhydrate and after any other secondary component, the bottoms that obtains comprises formic acid, residuary water and tertiary amine (I) in this particularly advantageous scheme.According to the present invention, then this can be sent into step (c).
If be also separated water outlet in the step (b) of the inventive method in addition to methanol, then the isolated water yield is generally the 10-100% be included in from the water yield in the stream of step (a).Preferably isolate in step (b) be included in from the water yield in the stream of step (a) >=20%, particularly preferably >=30% and preferably≤97%, particularly preferably≤95%.
Although the formation of the organic degradation product of tertiary amine (I) reduces the formation of the organic degradation product of tertiary amine (I) measure by the present invention significantly reduces, do not prevent completely.Therefore, isolate the organic degradation product of the tertiary amine (I) of removing according to the instruction of EP application 11194619.0 and they are discharged by the method together with water also advantageously in the methods of the invention.For this reason, by in step (b) the isolated stream comprising the organic degradation product of water and tertiary amine be separated into two liquid phases, removing comprise the organic degradation product of tertiary amine (I) upper phase and the lower floor's liquid phase comprising water is recycled in step (a).
Certainly, other processing steps beyond step (b) can be carried out in the methods of the invention between step (a) and (c).
Finally, by distillation plant under the pressure of the bottom temp of 100-300 DEG C and 30-3000hPa abs distillation and from step (b) taking-up formic acid.As the distillation plant for this object, those skilled in the art can be used in principle to become known for such equipment being separated task or general technical knowledge can be used to design by those skilled in the art.
This distillation plant not only comprises the actual tower body with internals usually, and especially comprises evaporator overhead condenser and bottom vaporizer.In addition, these can also comprise other minor equipments or internals naturally, such as, flasher (such as separating of the gas in tower body charging and liquid) in feeding line, middle vaporizer (such as improving the heat integration of the method) or the internals (such as can heat tower tray, mist eliminator, coalescer or dark bed diffusional filter) for avoiding or reduce aerosol to be formed.Tower body such as can equip orderly filler, loose heap packing elements or tower tray.Required theoretical plate number especially depend on tertiary amine (I) type, in step (c) desired concn of concentration in distillation plant charging of formic acid and tertiary amine (I) and formic acid or required purity, and can be determined in a usual manner by those skilled in the art.Required theoretical plate number usually >=3, preferably >=6, particularly preferably >=7.There is no the upper limit in principle.But, usually use usually≤70 for actual cause, optional≤50 blocks of theoretical trays or even≤30 blocks of theoretical trays.
The stream comprising formic acid and tertiary amine (I) from step (b) such as can feed the tower body in this distillation plant as side stream.
Flasher such as optionally also can be arranged before addition.In order to keep little as far as possible by the thermal stresses on the stream fed in distillation plant, usually advantageously fed the opposing lower portions region of this distillation plant.Therefore, the region, bottom 1/4 of the theoretical tray existing for stream infeed of formic acid and tertiary amine (I) preferably will be comprised in step (c), region, preferred bottom 1/5, particularly preferably region, bottom 1/6, here naturally also comprise and directly introduce bottom.
As replacement, the also preferred bottom vaporizer described stream comprising formic acid and tertiary amine (I) from step (b) being fed this distillation plant in step (c).
This distillation plant operates under the pressure of the bottom temp of 100-300 DEG C and 30-3000hPa abs.This distillation plant is preferably selected in >=and 120 DEG C, particularly preferably >=140 DEG C, and preferably≤220 DEG C, operate under the bottom temp of particularly preferably≤200 DEG C.This pressure preferably >=30hPa abs, particularly preferably >=60hPa abs, and preferably≤1500hPa abs, particularly preferably≤500hPa abs.
Depend on the feed composition comprising formic acid and tertiary amine (I) feeding this distillation plant, formic acid can be got product as top product and/or side and be obtained by this distillation plant.If this charging comprises the composition of boiling point lower than formic acid, then maybe advantageously isolate these as top product and isolate formic acid at lateral tap in this distillation.In gas dissolved situation possible in this charging, usually can also isolate formic acid as top product together with these.If this charging comprises the composition of boiling point higher than formic acid, then isolate formic acid preferably by distillation as top product, but optionally replace or go out formic acid at lateral tap with the second stream isolated in form extraly.Boiling point takes out in extra side-draw stream higher than the composition of formic acid boiling point is now preferred.This side-draw stream comprising secondary component can optionally be recycled in step (b) to isolate secondary component.
Can obtain in this way content at the most 100 % by weight formic acid.Usually can obtain the formic acid content of 75-99.995 % by weight no problemly.Reaching the surplus mainly water of 100 % by weight, naturally also can expecting that other components are if possible degradation production is as except introducing the formic acid in this distillation plant and the material except tertiary amine (I).
The concentrated formic acid being 95-100 % by weight at content is got in the separation of product as top product or side, and the formic acid be separated with a part in side-draw stream discharges water together.The formic acid content of this side-draw stream is generally 75-95 % by weight.Any point that water-containing formic acid in this side-draw stream can optionally be recycled in step (b) or in the method sentences separation water outlet.
But water and the formic acid of separation can also be discharged in common tower top or side-draw stream.The formic acid content of the product obtained in this way is now generally 85-95 % by weight.
In order to substantially suppress the formation of the organic breakdown products of especially tertiary amine (I)-formed by oxidation; particularly advantageously especially when distillation plant operates under the pressure lower than 0.1MPa abs, take special care in installation process by use sealing particularly preferred Flange joint (such as have comb shape sealing or weldering lip seal those) by nitrogen protection flange connect avoid oxygen pass through a large amount of web member, interface and flange invade or at least remain extremely low.Suitable Flange joint is disclosed in such as DE 10 2,009,046 310 A1.
Can there is low chromatic number and also have high chromatic number stability by formic acid obtained by the method for the present invention.Usually can realize≤20APHA, especially even≤10APHA, the chromatic number of if possible even≤5APHA no problemly.Even when stored for several weeks, chromatic number keeps substantially constant or only increases indistinctively.
Due to measure of the present invention, usually can without the need to obtaining the organic breakdown products of wherein tertiary amine (I) with paying further usually with≤70 weight ppm, the pure especially formic acid of the concentration existence of preferably≤30 weight ppm, very particularly preferably≤20 weight ppm.
In addition, the total content of secondary component (namely comprising the organic breakdown products of tertiary amine (I)) extremely low and usually≤100 weight ppm, preferably≤50 weight ppm, very particularly preferably≤25 weight ppm.
Also maybe advantageously in step (c), use multiple distillation plant, particularly when except free formic acid with containing also obtaining other cuts except amine (I) bottoms, the formic acid cut of the adjoint material such as comprised, byproduct of reaction, impurity and/or various purity and concentration.
Naturally hot lotus root be can also be configured to for separating of the distillation plant going out formic acid and distillation tower or partition wall tower closed.
In the preferred form of the inventive method, selection is ready to use in separation degree in the tertiary amine (I) in step (a) and the distillation plant mentioned in step (c) to make to form two liquid phases in the bottom output of the distillation plant mentioned in from step (c)
D bottom output from the distillation plant mentioned in step (c) is separated into two liquid phases by (), wherein the mol ratio of the formic acid that has of upper phase and tertiary amine (I) is the mol ratio of the formic acid that has of 0-0.5 and lower floor's liquid phase and tertiary amine (I) is 0.5-5;
E () will be recycled in step (a) from the upper phase be separated in step (d); And
F () is recycled to from the lower floor's liquid phase be separated in step (d) in step (b) and/or (c).
The formation of two liquid phases determines primarily of the chemistry of this two-phase and physicals.These again can by selecting the separation degree in stand-by tertiary amine (I), distillation plant and also having the existence of any additional component and affect.
For the purpose of the present invention, separation degree is following business:
Wherein " m formic acid(incoming flow of step (c)) " be that time per unit feeds amount of formic acid in distillation plant and " m formic acid(bottom output) " corresponding in the output of bottom time per unit discharge amount of formic acid.In this preferred embodiment of the inventive method, the separation degree of selection usually >=10%, preferably >=25%, particularly preferably >=40%, and usually≤99.9%, preferably≤99.5%, particularly preferably≤99.0%.Separation degree such as can easily by the temperature and pressure condition in distillation plant and the dwell time effect in distillation plant.It can be determined by simple experiment, optionally also determines in the operating process of the inventive method.
The suitability of tertiary amine (I) such as can be determined in the simple experiment determined under contemplated condition of the number of phase wherein.
Be separated and such as can carry out at the independent phase separator being arranged in distillation plant downstream.But, this phase separator can also be incorporated in the region in the bottom section of distillation plant, the region of bottom vaporizer or vaporizer loop, bottom.Here or such as centrifugal separator can also be even maybe advantageously used.
Because the formation of two liquid phases goes back temperature influence except the chemistry of two-phase and physicals and miscibility improves with temperature usually, maybe advantageously operate at the temperature lower than the bottom temp selected above and be separated, be separated to improve.For this reason, usually bottom output is cooled to the temperature of 30-180 DEG C in intermediate heat.Be separated and preferably at the temperature of≤160 DEG C, carry out particularly preferably at the temperature of≤130 DEG C at >=50 DEG C.
The mol ratio of the formic acid that the upper phase in step (d) has and tertiary amine (I) is generally 0-0.5, preferably >=0.005, particularly preferably >=0.015 and also preferably≤0.25, particularly preferably≤0.125.The mol ratio of the formic acid that the lower floor's liquid phase in step (d) has and tertiary amine (I) is generally 0.5-4, preferably >=0.75, particularly preferably >=1 and also preferably≤3.5, particularly preferably≤3.But, depend on the selection of amine, certainly can also be comprise formic acid form upper strata phase and the amine that formic acid/amine mol ratio is 0-0.5 forms lower floor's phase mutually mutually.Only importantly exist and be separated, wherein the formic acid had a mutually/tertiary amine mol ratio is generally 0-0.5 and formic acid/tertiary amine mol ratio that second-phase has is generally 0.5-4.The formic acid that upper strata preferably has mutually/tertiary amine mol ratio is generally the phase of 0-0.5 and formic acid/tertiary amine mol ratio that lower floor preferably has mutually is generally the phase of 0.5-4.
In addition, advantageously select the separation degree of the distillation plant mentioned in step (c) to make the mol ratio of formic acid and tertiary amine (I) in the output of bottom for 0.1-2.0 in the methods of the invention.For the purpose of the present invention, bottom output is for leaving distillation plant and be separated into whole liquid bottom condensation products of two liquid phases in step (d).Bottom condensation product be such as directly from bottom distillation plant, the bottom of bottom vaporizer or both unimportant.The separation degree of the distillation plant mentioned in preferred selection step (c) is to make the mol ratio of formic acid and tertiary amine (I) in the output of bottom preferably≤1.5.
Due to the upper phase be separated from middle step (d) is preferably recycled in step (a) according to step (e), the tertiary amine be included in upper phase (I) can be used for producing the stream comprising formic acid and tertiary amine (I) further by combining with formic acid source.Usually by 10-100%, preferred 50-100%, particularly preferably 80-100%, very particularly preferably 90-100%, especially the upper phase of 95-100% is recycled in step (a).
Certainly other processing steps can also be incorporated in the recirculation of upper phase.The limiting examples that can mention be such as from upper phase to be recycled or being included in wherein tertiary amine (I) removing undesirable with material, byproduct of reaction or impurity.The type of intervening process steps is unrestricted in principle.Can also as " purge stream " remove portion upper phase in a targeted way.The tertiary amine (I) of disappearance amount or this amount nature lost can be supplemented by the fresh tertiary amine (I) such as directly can introduced in step (a) via recycle stream again.
As mentioned above, although the measure being reduced the organic degradation product formation of tertiary amine (I) by the present invention significantly reduces the formation of the organic degradation product of tertiary amine (I), do not prevent completely.Therefore, advantageously go out to be gathered in the lower boiling organic degradation product from the tertiary amine (I) in the upper phase be separated in step (d) in the above-mentioned recirculation of upper phase with before these being discharged by the method by the fractionation by distillation of the instruction according to EP application 11194607.5 in the methods of the invention.
Lower floor's liquid phase makes the formic acid be included in lower floor's liquid phase may be used for the separating formic by distillation removing equally according to step (f) by from being preferably recycled in step (b) and/or (c) mutually of step (d).Depend on required embodiment, therefore lower floor's liquid phase can be recycled in (i) step (b), part is recycled in (ii) step (b) and part is recycled in (c) or is recycled in (iii) step (c).But, be usually preferably recycled in step (c) because the amount of stream does not increase in the now usually minimum and step (b) of the stress comprising lower floor's liquid phase of formic acid and tertiary amine (I), this otherwise size can be caused corresponding larger.Usually by 10-100%, preferred 50-100%, particularly preferably 80-100%, very particularly preferably 90-100%, especially lower floor's liquid phase of 80-100% is recycled in step (b) and/or (c).
Certainly other processing steps can also be incorporated in the recirculation of lower floor's liquid phase.As limiting examples, the purification of formic acid also can mentioned lower floor's liquid phase to be recycled or the tertiary amine (I) wherein comprised here and/or wherein comprise, undesirable with material, byproduct of reaction or impurity to remove.The type of intervening process steps is unrestricted in principle.All right as " purge stream " discharge section lower floor liquid phase in a targeted way, such as undesirable with material, byproduct of reaction or other impurity to remove.
Shockingly find that the carboxylic acid methyl quaternary ammonium salt formed in the formation of the organic degradation product of tertiary amine (I) under methyl-formiate exists can by the effect of heat in the context of the present invention, such as in still-process, part is converted into tertiary amine (I) again.A surprising especially aspect is the following fact: methyl is preferentially eliminated, although statistically this should only occur with the possibility of 25%.Therefore, such as carboxylic acid methyl three n-hexyl ammonium is dissociated into the three n-hexyl amine and methyl di-n-hexyl amine that ratio is 1:1 again due to distillation, instead of with the statistics being only 1:3 expection ratio.
Therefore, in the preferred version of the inventive method, in distillation plant, formic acid and tertiary amine (I) are distilled by from the lower floor's liquid phase be separated in step (d) and are recycled in one of above-mentioned steps (a)-(f) by the stream steamed in step (g) under the pressure of the bottom temp of 80-300 DEG C and 1-1000hPa abs.Preferably the stream steamed in step (g) is recycled in step (b).
Possible distillation plant for this object is that those skilled in the art become known for such equipment being separated task or current techique knowledge can be used to design by those skilled in the art in principle.Distillation plant operates under the pressure of the bottom temp of 80-300 DEG C and 1-1000hPa abs.Distillation plant, preferably at >=120 DEG C, particularly preferably >=140 DEG C, and preferably≤220 DEG C, operates under the bottom temp of particularly preferably≤200 DEG C.Pressure preferably >=5hPa abs, particularly preferably >=10hPa abs, and preferably≤500hPa abs, particularly preferably≤250hPa abs.
The stream comprising formic acid and tertiary amine (I) steamed obtains usually used as overhead product.But it can also obtain as side-draw stream, especially when also to isolate in distillation simultaneously relatively lower boiling component time.
In the methods of the invention, usually 0.01-50% is sent in step (g) from the lower floor's liquid phase be separated in step (d).First this amount is enough to dissociate this carboxylic acid methyl quaternary ammonium with abundant degree again, but secondly also will pay, and the size of such as distillation plant or the energy requirement carried out remain in limit.Preferably by >=0.1%, particularly preferably >=0.5%, also preferably≤20%, particularly preferably≤10%, very particularly preferably≤5% sends in step (g) from the upper phase be separated in step (d).
Therefore, even the organic degradation product conversion of part tertiary amine (I) can be got back to valuable tertiary amine (I) by step (g).
The tertiary amine (I) be preferably ready to use in the inventive method has general formula (Ia):
NR 1R 2R 3(Ia)，
Wherein radicals R 1-R 3identical or different and separately independently of each other in each case there is 1-16 carbon atom, the non-branching of a preferred 1-12 carbon atom or branching, acyclic or ring-type, aliphatic series, araliphatic or aromatic group, wherein single carbon atom can also be selected from the assorted group displacement of-O-and >N-and two or all three groups can also be combined with each other and form the chain comprising at least 4 atoms independently of each other.
The example of suitable amine is:
Three n-propyl amine (bp 1013hPa=156 DEG C), tri-n-butyl amine, three n-pentyl amine, three (3-methyl butyl) amine, three n-hexyl amine, three n-heptyl amine, three n-octylamine, three n-nonyl amine, three positive decyl amine, three n-undecane base amine, tridodecylamine, three n-tridecane base amine, three n-tetradecane base amine, three Pentadecane base amine, three n-hexadecyl amine, tris-(2-ethylhexyl)amine, three (2-propylheptyl) amine.
Dimethyl decyl amine, dimethyl dodecylamine, dimethyl tetradecyl amine, ethyl two (2-propyl group) amine (bp 1013hPa=127 DEG C), di-n-octyl methylamine, di-n-hexyl methylamine, di-n-hexyl (2-methyl-propyl) amine, di-n-hexyl (3-methyl butyl) amine, methyl two (2-ethylhexyl) amine, di-n-hexyl (1-methyl n-hexyl) amine, two-2-propyl group decyl amine.
Three cyclopentyl amine, thricyclohexyl amine, three cycloheptylaminos, three ring octyl amines and the derivative replaced by one or more methyl, ethyl, 1-propyl group, 2-propyl group, 1-butyl, 2-butyl or 2-methyl-2-propyl thereof.
Dimethylcyclohexylam,ne, methyldicyclohexyl amine, diethyl cyclo-hexylamine, ethyl dicyclohexylamine, dimethylcyclopentyl amine, methyl bicyclic amylamine, methyldicyclohexyl amine.
Triphenylamine, methyldiphenyl base amine, ethyl diphenyl amine, propyl group diphenylamine, butyl diphenyl amine, 2-ethylhexyl diphenylamine, 3,5-dimethylphenyl amine, diethyl phenyl amine, dipropyl phenyl amine, dibutylphenyl amine, two (2-ethylhexyl) phenyl amine, tribenzyl amine, methyl dibenzyl amine, ethyl dibenzyl amine and the derivative replaced by one or more methyl, ethyl, 1-propyl group, 2-propyl group, 1-butyl, 2-butyl or 2-methyl-2-propyl thereof.
1,5-bis-(piperidino) pentane, N-C 1-C 12alkylpiperidine, N, N-bis--C 1-C 12alkylpiperazine, N-C 1-C 12alkyl pyrrolidine, N-C 1-C 12the derivative that alkyl imidazole and one or more methyl, ethyl, 1-propyl group, 2-propyl group, 1-butyl, 2-butyl or 2-methyl-2-propyl replace.
1,8-diazabicyclo [5.4.0] 11 carbon-7-alkene (" DBU "), 1,4-diazabicyclo [2.2.2] octane, N-methyl-8-azabicyclo [3.2.1] octane (" scopolamine "), N-methyl-9-azabicyclo [3.3.1] nonane (" granatane "), 1-azabicyclo [2.2.2] octane (" rubane "), 7,15-diaza Fourth Ring [7.7.1.0 2,7.0 10,15] heptadecane (" Tocosamine ").
Nature can also use the mixture of various tertiary amine (I) in the methods of the invention.The naturally preferred boiling point had under the pressure of 1013hPa abs of all tertiary amines (I) now used is than the boiling point height at least 5 DEG C of formic acid.
Preferred wherein radicals R again in the above-mentioned tertiary amine of general formula (Ia) 1-R 3identical or different and separately independently of each other in each case there is 1-16 carbon atom, those of the non-branching of a preferred 1-12 carbon atom or branching, acyclic or ring-type, aliphatic series, araliphatic or aromatic group, wherein single carbon atom can also be selected from the assorted group displacement of-O-and >N-and two or all three groups can also be combined with each other and form the saturated chain comprising at least 4 atoms independently of each other.
Preferably at least one alpha-carbon atom, namely at the group directly and on the carbon atom of amine nitrogen atom bonding, there are two hydrogen atoms.
In the methods of the invention, wherein radicals R is particularly preferably used as tertiary amine (I) 1-R 3independently selected from C 1-C 12alkyl, C 5-C 8the amine of the general formula (Ia) of cycloalkyl, benzyl and phenyl.
In the methods of the invention, the saturated amine of general formula (Ia) is very particularly preferably used as tertiary amine (I).
Especially the amine of following general formula (Ia) is used as tertiary amine (I) in the methods of the invention, wherein radicals R 1-R 3independently selected from C 5-C 8alkyl and C 5-C 8cycloalkyl, especially three n-pentyl amine, three n-hexyl amine, three n-heptyl amine, three n-octylamine, dimethylcyclohexylam,ne, methyldicyclohexyl amine, dioctylmethylamine and dimethyl decyl amine.The most especially the amine of following general formula (Ia) is used as tertiary amine (I), wherein radicals R in the methods of the invention 1-R 3independently selected from C 5-C 8alkyl, especially three n-pentyl amine, three n-hexyl amine, three n-heptyl amine and three n-octylamine.
In further embodiment, be used in amine alpha-carbon atom (direct key is in the carbon atom of amine nitrogen atom), beta carbon (the second carbon atom of distance amine nitrogen atom) or gamma carbon atom (thricarbon atom of distance amine nitrogen atom) with side chain.Here can expect alkyl, aryl and other substituting groups in principle, preferred alkyl is as methyl, ethyl, 1-propyl group work-propyl group, or piperazine determines base.Particularly preferably N-ethylpiperidine, three (3-methyl butyl) amine, di-n-hexyl (2-methyl-propyl) amine, di-n-hexyl (3-methyl butyl) amine, methyl two (2-ethylhexyl) amine, di-n-hexyl (1-methyl n-hexyl) amine, two-2-propyl group decyl amine, methyldicyclohexyl amine, 1,5-bis-(piperidino) pentane in this embodiment.
The stream comprising formic acid and tertiary amine (I) formed in the methods of the invention not only can comprise free formic acid and free uncle amine (I), and can to comprise various other forms of formic acid and tertiary amine (I) with these mixture.Various forms of type and amount may because of prevailing conditionss, such as formic acid and the relative proportion of tertiary amine (I), the existence of other components (such as water, by product, impurity) and the therefore finally concentration of formic acid and tertiary amine (I), temperature and pressure and different in addition.Therefore, the following form expected can such as be mentioned:
-ammonium formiate (mol ratio of formic acid and tertiary amine (I) is 1) or be rich in formic acid with the adducts (the mol ratio >1 of formic acid and tertiary amine (I)) of tertiary amine (I).
-ionic liquid.
Various forms of type is unimportant for enforcement the inventive method with amount.
Fig. 1 illustrates the simplified block diagram of the general embodiment of the inventive method.In the figure, each letter has following meanings:
A1=produces the first workshop section comprising the equipment of the stream of formic acid, tertiary amine (I) and water
A2=produces the second workshop section comprising the equipment of the stream of formic acid, tertiary amine (I) and water
B=isolates the equipment of methyl alcohol and other secondary components optional
C=distillation plant
Methyl-formiate is fed the first workshop section A1 of the equipment for the production of the stream comprising formic acid, tertiary amine (I) and water via stream (1a) and water via stream (1b).According to the present invention, a certain amount of tertiary amine (I) can also be introduced via stream (1c).But, tertiary amine (I) is added in A1 and also can be omitted.In FIG, this is shown by dotted arrow.Hydrolysis reaction occurs in A1 at least partially.Then reaction mixture is fed the second workshop section A2 of the equipment for the production of the stream comprising formic acid, tertiary amine (I) and water by the first workshop section A1 via stream (1x).The reinforced of tertiary amine (I) carries out via stream (1d).The stream (2) comprising formic acid, tertiary amine (I) and water is taken out by the second workshop section A2 of aforesaid device subsequently and sends to removing methyl alcohol and optionally other secondary components in deviceb.This is preferably distillation plant.Isolated methyl alcohol and any other secondary component take out via stream (3).The stream being rich in formic acid and tertiary amine (I) feeds in distillation plant C via stream (4).By distillation, formic acid is separated as stream (5) wherein.Bottoms from distillation plant C takes out as stream (6).
If equipment B is preferred distillation plant, then this can also have configuration disclosed in Figure 12-13 of such as WO 2012/000,964.Distillation plant C such as can have WO 2012/000, configuration disclosed in Fig. 2-7 of 964.
Fig. 2 illustrates the simplified block diagram of modification embodiment, wherein the second workshop section A2 of equipment for the production of the stream comprising formic acid, tertiary amine (I) and water is divided into Liang Gezi workshop section A2-i and A2-ii.Tertiary amine (I) is introduced via stream (1d-i) and (1d-ii) in each case.Device A 1, A2, B and C have implication shown in Fig. 1.
Fig. 3 illustrates another simplified block diagram of modification embodiment, wherein the second workshop section A2 of equipment for the production of the stream comprising formic acid, tertiary amine (I) and water is divided into sub-workshop section A2-i, A2-ii, the A2-iii to A2-z of theory unlimited number.Tertiary amine (I) is introduced via stream (1d-i), (1d-ii), (1d-iii) to (1d-z) in each case.Equipment same A1, A2, B and C have implication shown in Fig. 1.
The preferred embodiment being obtained formic acid by hydrolysis methyl-formiate is shown in the Fig. 4 by simplified block diagram.In the figure, each letter has following meanings:
A1=produces the first workshop section comprising the equipment of the stream of formic acid, tertiary amine (I) and water, and it comprises sub-workshop section A1-i and A1-ii
A2=produces the second workshop section comprising the equipment of the stream of formic acid, tertiary amine (I) and water, and it comprises sub-workshop section A2-i and A2-ii
B=isolates the distillation plant of methyl alcohol and other secondary components optional
C=obtains the distillation plant of formic acid
D=phase separation container
E=phase separation container
F=isolates the distillation plant of low-boiling-point substance
G=isolates high boiling material and the distillation plant of the carboxylic acid methyl quaternary ammonium that dissociates again
Y=metering outfit
Methyl-formiate (stream (1a) and (3b)) and water (stream (1b) and (3x)) are fed the first workshop section A1 for the production of the equipment of the stream comprising formic acid, tertiary amine (I) and water and mixes in sub-workshop section A1-i.There is not the hydrolysis of slight part wherein.Then fed by reaction mixture in sub-workshop section A1-ii, first this sub-workshop section has the function stopping container also provides reaction mixture to balance the enterprising single step reaction in direction in time.Then reaction mixture is entered the second workshop section A2 of the equipment for the production of the stream comprising formic acid, tertiary amine (I) and water via stream (1x) by this stop container.This is divided into Liang Gezi workshop section equally.In sub-workshop section A2-i, the tertiary amine (I) of first part adds via metering outfit Y and stream (8d), thus formic acid can be reacted with tertiary amine (I).In addition, also there is the further hydrolysis of methyl-formiate.Then reaction mixture is sent into sub-workshop section A2-ii, introduce tertiary amine (I) via metering outfit Y and stream (8e) equally wherein.The further reaction of formic acid and added tertiary amine (I) and also have the further hydrolysis of methyl-formiate to occur in sub-workshop section A2-ii.As the equipment of A1 and A2, the transition position such as between each workshop section and Ge Zi workshop section can be used to have the tubular reactor of orifice plate.Temperature in reactor advantageously regulates by embedded interchanger (such as cooling worm) and by the temperature of the tertiary amine (I) in goal-setting A2-i and A2-ii to be added.
Then reaction mixture to be taken out by device A 2-ii as stream (2) and feed in equipment B.Stream (2) mainly comprises formic acid, tertiary amine (I), methyl alcohol, water and unreacted methyl-formiate.
In distillation plant B, the organic breakdown products (stream (3c)) of unreacted methyl-formiate (stream (3b)), the methyl alcohol (stream (3a)) formed in hydrolysis and water and tertiary amine (I) is separated from stream (2).The stream (3b) comprising unreacted methyl-formiate is recycled in device A 1.Such as can be used further to prepare methyl-formiate via stream (3a) isolated methyl alcohol.The stream (3c) comprising the organic degradation product of water and tertiary amine (I) to be fed in phase separation container E and to be separated into two liquid phases.The lower floor comprising water is recycled in device A 1 as stream (3x).The upper strata of the organic degradation product comprising tertiary amine (I) is discharged by the method.Formic acid and tertiary amine (I) take out via stream (4).This additionally comprises the water of residual quantity.
Stream (4) is fed in distillation plant C.Wherein by distillation via stream (5) as overhead product, via stream (5a) as side line product and/or via stream (5b) as side line product take out formic acid.Depend on final condition, the i.e. especially composition of incoming flow (4) of distillation plant C and the required purity of formic acid, formic acid can obtain with side line product at top or as stream (5a) as stream (5) in this embodiment.Then take out via stream (5a) or (5b) formic acid comprising water as side line product.In some cases, may even be sufficient that purely take out formic acid via stream (5) as overhead product or comprise the formic acid of water.Therefore, depend on specific embodiments, can omit side-draw stream (5b) or even side-draw stream (5a) and (5b) the two.
Bottoms from distillation plant C is fed in phase separation container D as stream (6).As replacement, also phase separation container D can be incorporated in distillation plant C.In phase separation container D, bottoms is separated into two liquid phases.Such as can also optionally interchanger be arranged between distillation plant C and phase separation container D to cool the bottom stream of taking out.Although lower phase separation temperature causes a little better being separated with regard to formic acid content usually, it causes extra expenditure and energy consumption owing to using interchanger.Therefore, balance mutually must be done to merits and demerits in each case.
From phase separation container D lower floor's liquid phase as stream (7a) take out and be recycled in distillation plant C as stream (7b).In preferred embodiments, can extraction portion part-streams (7a) it can be used as stream (7c) to feed in distillation plant G.In addition or as replacing, also other streams unshowned here can be supplied to distillation plant G.Therefore, the subflow of the bottom output from distillation plant C such as can be expected to introduce in distillation plant G.There this stream under reduced pressure distilled and part carboxylic acid methyl quaternary ammonium is dissociated into tertiary amine (I) again, take out at top the stream comprising formic acid and tertiary amine (I) and it can be used as stream (7d) to feed in distillation plant B.Bottoms is discharged by the method.
The operational condition of distillation plant G, the amount of such as pressure, temperature, the residence time, incoming flow is generally the compromise of well dissociating between condition of carboxylic acid methyl quaternary ammonium under very low formic acid degree of decomposition.If inoperation distillation plant G, then carboxylic acid methyl quaternary ammonium is assembled in the method, especially in the bottoms from distillation plant C and the lower floor from phase separation container D mutually in, thus make the method have relevant and above-mentioned negative consequences.
Upper phase from phase separation container D is taken out via stream (8a) and is recycled in metering outfit Y.Metering outfit Y such as can be to provide filling level measure and two for distributing the storage tank of the adjustment volume pump of stream (8d) and (8e).In addition, metering outfit Y can also comprise heating or the cooling element of the temperature for controlling stream (8d) and (8e).Subflow (8b) is fed in distillation plant F.Pass through distillation wherein remove low-boiling-point substance as stream (8z) and the poor stream containing low-boiling-point substance is recycled in metering outfit Y as stream (8c).
Obtaining in another preferred embodiment of formic acid by hydrolysis methyl-formiate, methyl-formiate stream (1a) is not directly being introduced in workshop section A1-i, but introducing in distillation plant B.This embodiment usually the methyl-formiate that can obtain as stream (1a) such as due in front methyl-formiate synthesizing section methanol fractions transform and the incomplete aftertreatment of methyl-formiate still polluted by the methyl alcohol of residual quantity time be favourable.As the result directly introduced by stream (1a) in distillation plant B, the methyl alcohol comprised can be separated as stream (3a) and such as can be recycled in methyl-formiate synthesizing section.The program makes it possible to omit methyl-formiate/separating methanol completely in methyl-formiate synthesizing section and therefore saves whole distillation tower and therefore also conserve energy in the operation carried out.
Obtaining in another preferred embodiment of formic acid by hydrolysis methyl-formiate, both methyl-formiate stream (1a) and water stream (1b) are not directly being introduced in workshop section A1-i separately, but introducing in distillation plant B.For water stream (1b), this embodiment can as normally favourable during water source at hot condensate or steam, because the heat energy wherein stored can be used in distillation plant B in this way.
For the purpose of complete, can mention nature in another embodiment can also introduce methyl-formiate stream (1a) in device A 1-i, and is introduced in distillation plant B by water stream (1b).This is such as favourable when low pressure excess steam is available.
In this embodiment, be possible with regard to the concrete scheme with regard to there is the embodiment of 1,2 or the even distillation plant B of 3 distillation towers, as such as at WO 2012/000, disclosed in Figure 12-13 of 964.The scheme with 1 or 2 distillation tower is preferred for the design of distillation plant B.For the purpose of complete, can mention particularly in the embodiment with 1 or 2 distillation tower, these can also be configured to hot lotus root and close tower or partition wall tower.
The stream that the inventive method makes it possible to comprise formic acid and tertiary amine by thermal separation obtains formic acid with high yield and high density by methyl-formiate.
The formation of the organic degradation product of undesirable tertiary amine (I) effectively can reduce by merging the classification of methyl-formiate, water and tertiary amine (I) according to the present invention.This makes even is not having target removing and yet these concentration in this system can remained on low-level in the time durations extended and significantly reduce counter productive under discharging described degraded product.In addition, the irreversible decomposition because of measure of the present invention of significantly less tertiary amine, thus significantly less fresh amine must be introduced by outside.This makes the method not only simpler but also alleviate the pressure to environment by more low consumption.
Especially with remove and discharge the additional measures of the organic degradation product of the tertiary amine (I) still formed on a small quantity, such as, described in EP application 11 194 619.0 and EP application 11 194 607.5, measure combines, and especially effectively can offset the gathering gradually of low-boiling-point substance.Therefore the shortcoming energy consumption such as comprising the distillation plant of the stream of formic acid and tertiary amine for thermal separation especially effectively can avoided slowly to improve and also have formic acid quality to be slowly deteriorated because of the pollution raising of low-boiling-point substance.Can also be used in removing because of measure of the present invention and discharge the equipment of above-mentioned degraded product much smaller, this gives additional advantage on processing unit and the operation carried out.
The inventive method can very stably operate, and the formic acid simultaneously produced within the prolongation operating time has constant high purity.Gained formic acid has low chromatic number and high chromatic number stability.The method can simply, reliable and implement with less energy-consumption.
Experimental installation 1
Experimental installation 1 is used for checking this continuation method.The simplified block diagram of experimental installation 1 is shown in Figure 5.In the figure, each letter has following meanings:
A1=produces the first workshop section comprising the equipment of formic acid, tertiary amine (I) and water, and it comprises sub-workshop section A1-i and A1-ii
A1-i=stirred vessel (volume 0.3L, electrically heated)
A1-ii=tubular reactor (internal diameter 80mm, long 1200mm fill 2mm glass sphere, electrically heated)
A2=produces the second workshop section comprising the equipment of formic acid, tertiary amine (I) and water, and it comprises sub-workshop section A2-i and A2-ii
A2-i=tubular reactor (internal diameter 80mm, long 1200mm fill 2mm glass sphere, electrically heated)
A2-ii=tubular reactor (internal diameter 80mm, long 1200mm fill 2mm glass sphere, electrically heated)
Y=is as the container (5L volume) of gauging tank
B1=comprises tower body, and (internal diameter 55mm, it is 1.3m and specific surface area is 750m separately that two packing heights are housed 2/ m 3screen cloth filler, wherein the entrance of stream (2) is between these two sieve king net fillers), oily heat drop film evaporator and condenser and also have distillation plant at the adjustable reflux sparger of tower top
B2=comprises tower body (internal diameter 55mm, 12 bubble decies in stripping stage and 10 bubble decies in the richness section of amassing are housed, wherein the entrance of stream (3d) between these two sections and the entrance of stream (5b) is arranged in stripping stage), oily heat drop film evaporator and condenser and also have distillation plant at the adjustable reflux sparger of tower top
(internal diameter 43mm, the packing height be equipped with above at the bottom of tower is 0.66m and specific surface area is 500m for C1=tower body 2/ m 3screen cloth filler and packing height is 0.91m and specific surface area is 750m 2/ m 3another screen cloth filler, wherein the side material taking mouth of stream (5b) between these two lower screen fillers and the side material taking mouth of stream (5a) between these two upper screen fillers) and condenser and also having at the adjustable reflux sparger of tower top
C2=oil heat drop film evaporator
The phase separation container (volume 0.3L, oil heat) that D=separates
E=phase separation container
F=has tower body, and (internal diameter 30mm is equipped with 1m Sulzer CY filler (750m 2/ m 3), wherein the entrance of stream (9a) is positioned under this filler), oily hot bottom container and also having at the distillation plant of the adjustable reflux divider of tower top
G=is for removing high boiling material and the evaporation equipment of the carboxylic acid methyl quaternary ammonium that dissociates again (volume is 2L and has the Glass Containers of oil operation heating coil)
Equipment and pipeline are made up of the nickel-base alloy of material number 2.4610.By Coriolis flowmeter measurement quality flow velocity.Experimental installation 1 operate continuously.
In all tests in experimental installation 1, formic acid content passes through in each case to measure with the titration of 0.5NNaOH electric potential of water solution and the content of water is measured by Karl Fischer method.Every other organic constituent passes through gas chromatography determination in each case.
Experimental installation 2
Experimental installation 2 is for checking the decomposition of formic acid under carboxylic acid methyl three n-hexyl ammonium exists.It comprises evaporation another the cooled container L of vaporized media condensation by heating double walled glass K and internal volume being 1L that internal volume is 1L.The hot heating coil of oil is positioned at the bottom of the inner vessels of this double walled glass K.In addition, this double-walled is also heated by oil.In order to regulate the flow entering this double walled glass K, this container comprises liquor-level regulator.Between K and L, there is condenser, the steam condensation wherein from K is also directly introduced in L.Container L comprise condensation product liquid outlet and gaseous component export both.Liquid level in container L is always high enough to the condensed steam from K to introduce under fluid surface.Under meter is arranged in the outlet of gaseous component.
Measure the content of carboxylic acid methyl three n-hexyl ammonium
The mensuration of carboxylic acid methyl three n-hexyl ammonium content is undertaken by ion chromatography.In order to analyze even lower concentration, each mensuration uses about 1L sample to carry out.First at the decompression of 3hPa abs (3 millibars of abs) and 30 DEG C, low-boiling-point substance (especially methyl-formiate, first alcohol and water) is evaporated.The sample comprising formic acid, three hexyl amines, carboxylic acid methyl three n-hexyl ammonium and boil in other if possible thing and high boiling material is neutralized by the 50%NaOH aqueous solution.This forms three-phase: the heavy phase comprising aqueous sodium formate solution, comprises mesophase spherule and the apolar amines upper strata phase of carboxylic acid methyl three n-hexyl ammonium.These are separated from each other mutually and in mesophase spherule, measure the content of carboxylic acid methyl three n-hexyl ammonium by ion chromatography.
Measure the content of carboxylic acid methyl three amyl group ammonium and carboxylic acid methyl three n-octyl ammonium
Except by except ion-chromatographic determination, also by the dissociating product of gas chromatography determination carboxylic acid methyl three n-hexyl ammonium.Here find that undetectable methyl dihexyl amine is characteristic dissociating product in fresh three n-hexyl amine.Together with the result of ion chromatography, carboxylic acid methyl three n-hexyl ammonium therefore also can via its degraded product with gc analysis.This calibration is for measuring carboxylic acid methyl three amyl group ammonium and carboxylic acid methyl three n-octyl ammonium.Here about 1L is used to react the sample of output in each case.Low-boiling-point substance (especially methyl-formiate, first alcohol and water) first evaporates under 30 DEG C of decompressions with 3hPa abs (3 millibars of abs).Then the sample 50%NaOH aqueous solution neutralization of formic acid, trialkylamine, carboxylic acid methyl trialkyl ammonium and boil in other if possible thing and high boiling material will be comprised.This causes forming three-phase: the heavy phase comprising aqueous sodium formate solution, comprises mesophase spherule and the apolar amines upper strata phase of carboxylic acid methyl trialkyl ammonium.These are separated from each other mutually and in mesophase spherule, measure the content of carboxylic acid methyl trialkyl ammonium by above-mentioned vapor-phase chromatography.
Embodiment 1 (embodiment of the present invention in experimental installation 1)
Embodiment 1 is carried out in experimental installation 1.By volume pump, 2280g/h methyl-formiate is metered in stirred vessel A1-i via stream (1b) via stream (1a) and 950g/h water.The storage tank (not shown in Figure 5 for the sake of simplicity) being 5L by methyl-formiate and water in each case by volume in each case takes out and introduces fresh methyl-formiate and recycled water wherein via stream (3b) and (3e).Stirred vessel A1-i operates under 110 DEG C and 1.3MPa abs.Output from A1-i is introduced in the tubular reactor A1-ii operated under 110 DEG C and 1.3MPa abs equally.Ratio n (introducing the amine of a1)/n (introducing the methyl-formiate of a1) is therefore 0.Mean residence time is 5 minutes and is 36 minutes in tubular reactor A1-ii in A1-i.The transformation efficiency realized in the exit of A1-ii is at 87% of the lower hydrolysising balance that imposes a condition.Then the output from A1-ii is introduced in tubular type reactor A 2-i via stream (1x).1949g/h tri-n-hexyl amine is introduced wherein via the storage tank Y that stream (8d) is 5L by volume.Temperature in A2-i is 105 DEG C and pressure is 1.3MPa abs.Mean residence time in A2-i is 22 minutes.92% of equilibrium conversion is realized in from the reaction output of A2-i.Output from A2-i is introduced in tubular type reactor A 2-ii, via stream (8e), other 1947g/h tri-n-hexyl amine is introduced wherein by container Y.Tubular reactor A2-ii operates equally under 105 DEG C and 1.3MPa abs.Ratio n (introducing the amine of a2)/n (introducing the methyl-formiate of a1) is therefore 0.38 and ratio n (introducing the amine of a)/n (introducing the methyl-formiate of a) is similarly 0.38.The product mixtures of 49.2 % by weight three n-hexyl amine, 16.7 % by weight formic acid, 11.8 % by weight methyl alcohol, 7.2 % by weight water and 11.1 % by weight methyl-formiates is obtained comprising as stream (2).
Stream (2) is reduced pressure and introduces in the tower body of distillation plant B1.In addition, via stream (5b), 88g/h is fed in distillation plant B1 from the rich water side-draw stream comprising 82.7 % by weight formic acid and 17.3 % by weight water of the tower body of distillation plant C1.0.18MPa abs top pressure and 1.95 reflux ratio under as overhead product take out methyl-formiate and as side line product take out methyl alcohol.Methyl-formiate is recycled in stirred vessel A1-i as stream (3b).Obtain with stream (3d) mixture that 5790g/h comprises 71.2 % by weight three n-hexyl amine, 9.1 % by weight water, 20.7 % by weight formic acid and 0.1 % by weight methyl alcohol as bottoms.The bottom temp of B1 is 119 DEG C.
Stream (3d) is introduced in the tower body of distillation plant B2.In addition, via stream (5a), 43g/h is fed in distillation plant B2 with the relative low water side-draw stream of 17.1 % by weight water from 83.2 % by weight formic acid that comprise of distillation plant C1 tower body.In addition, also the condensing steam stream of the equipment of self-evaporatint n. in the future G feeds in distillation plant B2 via stream (7c).The bottom temps of 177 DEG C, 0.18MPa abs top pressure and 0.26 reflux ratio under using the amount of 594g/h and 98.1 % by weight water-content as from B2 overhead product take out stream (3c) and feed at 100 DEG C operation phase separation container E in.By wherein taking out stream (3e) and being recycled in stirred vessel A1-i via storage tank at the bottom of tower.Start some days at this device slowly to be formed afterwards and comprise the organic degradation product of isolated three n-hexyl amine and another upper strata phase of water.Then every day this upper strata is removed as stream (3y).
Obtain by distillation plant B2 the mixture that 5496g/h comprises 66.8 % by weight three n-hexyl amine, 24.7 % by weight formic acid and 1.1 % by weight water as bottoms.Stream (4) is it can be used as to feed vaporizer C2 by top.In addition, also vaporizer C2 is fed by from the stream (6a) bottom tower body C1 with from the stream (7a) of lower floor's liquid phase of phase separation container D.Vaporizer C2 and tower body C1 under reduced pressure operates.The temperature at vaporizer C2 lower part outlet place is 156 DEG C.The output of flash-pot feeds tower body C1 as stream (6x) in the future.The reflux ratio of this top pressure at 150hPa abs and reflux and distillate is operate for 3 times.As the overhead product from C1, obtain with stream (5) formic acid that 987g/h concentration is 99.6 % by weight.The content <10 weight ppm of the just own ester of formic acid in stream (5) and evaluated for hexanal content <15 weight ppm.Side-draw stream (5a) to be recycled in distillation plant B2 and side-draw stream (5b) is recycled in distillation plant B1.With the amount of 5024g/h by taking out stream (6b) bottom tower body C1 and introducing phase separation container D.In addition, evaporation equipment G is fed as stream (6c) by the stream taking out 147g/h bottom tower body C1.
Phase separation container D operates at the temperature of barometric point and 80 DEG C.Form two liquid phases.Upper phase is taken out continuously using the amount of 3945g/h as stream (8) and is transported in container Y via stream (8a).Stream (8) comprises 94.1 % by weight three n-hexyl amine and 1.9 % by weight formic acid.Lower floor's liquid phase is taken out as stream (7a) and is transported in vaporizer C2 continuously.Take out 80g/h stream as stream (7b) by lower floor liquid phase abreast therewith and feed evaporation equipment G.
Evaporation equipment G operates at the temperature of the pressure of 20hPa abs and 165 DEG C.Vapour condensation is introduced distillation plant B2 as stream (7c).After the operating time of 2 months by evaporation equipment G cool, decompression and emptying.Discharged by the amount of taking out about 1100g at the bottom of tower as stream (7z).Stream (7z) comprises high boiling material as higher molecular weight secondary component and also have trace from the metal of this equipment.
Take out 33g/h by stream (8) via stream (8b) and feed distillation plant F.Take out 0.5g/h distillate as stream (8z) and abandon under the bottom temp of the pressure of 15hPa abs and 162 DEG C.Residuum is fed in container Y as stream (8c).
In order to ensure steady state operation, first by this plant running 14 days, then sampled by the output (stream (1y)) from tubular reactor A2-i and analyzed the content to measure carboxylic acid methyl three n-hexyl ammonium.The concentration of carboxylic acid methyl three n-hexyl ammonium in this stream is 83 weight ppm.
Embodiment 2 (embodiment of the present invention in experimental installation 1)
Embodiment 2 is carried out, unlike change as follows in the mode being similar to embodiment 1:
-stirred vessel A1-i and tubular reactor A1-ii operates at 130 DEG C.
-hydrolysising balance is 88% in from the output of A1-ii.
-stream (8d) is 1944g/h.
-tubular reactor A2-i operates at 128 DEG C.
-hydrolysising balance is 93% in from the output of A2-i.
-stream (8e) is 1945g/h.
-tubular reactor A2-ii operates at 131 DEG C.
Therefore ratio n (introducing the amine of a1)/n (introducing the methyl-formiate of a1) is similarly 0, and ratio n (introducing the amine of a2)/n (introducing the methyl-formiate of a1) is similarly 0.38.Ratio n (introducing the amine of a)/n (introducing the methyl-formiate of a) is also 0.38 in the same manner.
In order to ensure steady state operation, first the condition of this device in embodiment 2 is run until guarantee 5 times of exchanges in all device features, then sampled by the output (stream (1y)) from tubular reactor A2-i and analyzed the content to measure carboxylic acid methyl three n-hexyl ammonium.The concentration of carboxylic acid methyl three n-hexyl ammonium in this stream is 508 weight ppm.
This device during the several months in operate with stationary mode.
Embodiment 1 and 2 shows that the inventive method can operate with stationary mode in the time range extended.The content of carboxylic acid methyl three n-hexyl ammonium is 83 weight ppm (=0.0083 % by weight) in embodiment 1 and is 508 weight ppm (=0.0508 % by weight) in example 2, is all in relatively little scope.But these two embodiments also show that the formation of carboxylic acid methyl three n-hexyl ammonium improves along with hydrolysis temperature in step (a2) and significantly increases.About 130 DEG C that temperature are brought up in embodiment 2 by 105 in embodiment 1 DEG C cause carboxylic acid methyl three n-hexyl ammonium content to improve about 5 times.
Embodiment 3-5 (forming carboxylic acid methyl three n-hexyl ammonium in experimental installation 1)
To device A 1 (comprising A1-i and A1-ii), the A2 (comprising A2-i and A2-ii) and Y of embodiment 3-5 only operation experiments device 1.Fresh methyl-formiate and fresh water are introduced via stream (1a) and (1b) respectively and introduced via stream (8d) and (8e) by the fresh three n-hexyl amine from container Y.Analyze stream (1y) to measure its carboxylic acid methyl three n-hexyl ammonium content.Processing condition and result are shown in Table 1.
Under embodiment 3-5 shows condition similar in other respects, the formation of carboxylic acid methyl three n-hexyl ammonium the reinforced segmentation of three n-hexyl amine in step (a2) is caused to reduce.Therefore, in non-division reinforced embodiment 3, stream (1y) comprises 770 weight ppm carboxylic acid methyl three n-hexyl ammoniums, and stream (1y) only comprises 508 weight ppm in the embodiment 4 of 50%/50% segmentation.In addition, these embodiments show that the formation of the carboxylic acid methyl three n-hexyl ammonium when condition decline low in hydrolysis temperature similar in other respects significantly reduces.Therefore, the stream (1y) under the hydrolysis temperature of about 130 DEG C in embodiment 4 comprises 508 weight ppm carboxylic acid methyl three n-hexyl ammoniums, and the stream (1y) under the hydrolysis temperature of about 105 DEG C in embodiment 4 only comprises 83 weight ppm.
Embodiment 6-8 (under carboxylic acid methyl three n-hexyl ammonium exists decompose formic acid)
Embodiment 6-8 is carried out in experimental installation 2.Here the stream comprising formic acid, three n-hexyl amine (THA), methyl di-n-hexyl amine (MDHA), carboxylic acid methyl three n-hexyl ammonium (MTHA formate), di-n-hexyl methane amide (DHF) and water is fed by the double walled glass K that heats, to make there is about 1L in each case wherein with regulated quantity.Vaporized component is condensation collecting at about 20 DEG C in container L.Amount from the gaseous output of container L measures by under meter.This gaseous output additionally by gc analysis to measure the volume of hydrogen, carbonic acid gas and carbon monoxide.Processing condition and result are shown in Table 2.
Embodiment 6-8 shows that the decomposition of formic acid under condition similar in other respects significantly increases along with the concentration of carboxylic acid methyl three n-hexyl ammonium.Therefore, such as in embodiment 7,7.4% formic acid introduced is decompose for 0.08 % by weight time in MTHA formate content, and is that 0.68 % by weight time this value is 13.5% and is that 1.7 % by weight times these values are up to 23.9% in MTHA formate content in embodiment 6 in MTHA formate content in embodiment 8.The level (relative change about ± 12%) that other organic degradation products of three n-hexyl amine (THA) and THA are as closely similar in the content of MDHA with DHF is in these embodiments.
Therefore, embodiment 6-8 most clearly show as the MTHA formate of the representative of carboxylic acid methyl quaternary ammonium strongly promote formic acid do not wish decompose and therefore its concentration should keep very low in the method for this acquisition formic acid ideally.Say exactly, this is realized by measure of the present invention.
Embodiment 9-10 (dissociating again of carboxylic acid methyl three n-hexyl ammonium)
Embodiment 9
Mixture 118.0g being comprised 12.6g formic acid and 105.4g tri-n-hexyl amine (THA) is introduced in 1L double walled glass.Can't detect methyl di-n-hexyl amine (MDHA) in the mixture.This reaction soln is heated to 163 DEG C.The pressure of 250 millibars is applied by vacuum pump.Make it possible to discharge lower boiling secondary component as methyl-formiate by waving funnel, and do not lose more high boiling component as MDHA.Introduce the solution that 12.5g comprises 7.6g carboxylic acid methyl three n-hexyl ammonium, 2.0g formic acid and 2.9g tri-n-hexyl amine.This mixture is maintained 6.1 hours at the preset temperature.99.5g two-phase mixture is obtained as output.In order to ammonium formiate content can be measured by analyzing, adding 50.5g formic acid to carry out homogenizing after cooling, obtaining the output that total mass is 150.1g.In this solution, the carboxylic acid methyl three n-hexyl ammonium that residual content is 3.71 % by weight is recorded by ion chromatography.Therefore, still there is 5.6g carboxylic acid methyl three n-hexyl ammonium after the reaction, display 2.0g carboxylic acid methyl three n-hexyl ammonium decomposes (=26.3%) in this reaction process.In addition, in reaction output, 0.6g MDHA is detected by vapor-phase chromatography.This amount is in mole corresponding to 1.0g carboxylic acid methyl three n-hexyl ammonium.
Embodiment 10
Mixture 122.2g being comprised 12.2g formic acid and 110.0g tri-n-hexyl amine (THA) is introduced in 1L double walled glass.This reaction soln is heated to 173 DEG C.The pressure of 300 millibars is applied by vacuum pump.Make it possible to discharge lower boiling secondary component as methyl-formiate by waving funnel, and do not lose more high boiling component as methyl di-n-hexyl amine (MDHA).Introduce the solution that 11.6g comprises 7.0g carboxylic acid methyl three n-hexyl ammonium, 1.9g formic acid and 2.7g tri-n-hexyl amine.This mixture is maintained 6.1 hours at the preset temperature.121.3g two-phase mixture is obtained as output.In order to carboxylic acid methyl three n-hexyl ammonium content can be measured by analyzing, adding 34.5g formic acid to carry out homogenizing after cooling, obtaining the output that total mass is 155.8g.In this solution, the carboxylic acid methyl three n-hexyl ammonium that residual content is 2.32 % by weight is recorded by ion chromatography.Therefore, still there is 3.6g carboxylic acid methyl three n-hexyl ammonium after the reaction, display 3.4g carboxylic acid methyl three n-hexyl ammonium decomposes (=48.6%) in this reaction process.In addition, in reaction output, 1.1gMDHA is detected by vapor-phase chromatography.Therefore, 1.7g carboxylic acid methyl three n-hexyl ammonium resolves into MDHA.
Embodiment 9 and 10 clearly illustrates that carboxylic acid methyl three n-hexyl ammonium dissociates at elevated temperatures and the carboxylic acid methyl three n-hexyl ammonium that dissociates of 50% is dissociated into MDHA.
Embodiment 11-13 (segmentation that amine feeds in raw material is on the impact being formed carboxylic acid methyl three n-hexyl ammonium by three n-hexyl amine)
Embodiment 11
600g methyl-formiate, 252g water and 1076g tri-n-hexyl amine to be introduced in autoclave and to maintain 130 DEG C and lower 2 hours of 25 bar abs.Then this autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 17.5 % by weight formic acid, 6.5 % by weight water and 14.1 % by weight methyl alcohol and also has the mixture of 0.16 % by weight carboxylic acid methyl three n-hexyl ammonium.Test conditions and the analytical value chosen are shown in table 3a and 3b.
Embodiment 12
600g methyl-formiate and 252g water to be introduced in autoclave and to maintain 130 DEG C and lower 1 hour of 25 bar abs.Then inject 1076g tri-n-hexyl amine and this mixture is maintained 1 hour again under 130 DEG C and 25 bar abs.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 16.3 % by weight formic acid, 6.5 % by weight water and 13.6 % by weight methyl alcohol and also has the mixture of 0.11 % by weight carboxylic acid methyl three n-hexyl ammonium.Test conditions and the analytical value chosen are shown in table 3a and 3b.
Compared with embodiment 11, under condition identical in other respects under formation identical amount (in analysis precision) formic acid because progressively adding methyl-formiate and water according to the present invention and progressively add tertiary amine and form significantly less carboxylic acid methyl three n-hexyl ammonium (being in a ratio of 0.11 % by weight with 0.16 in embodiment 11 % by weight) in workshop section (a2) in workshop section (a1).This corresponds to the relative reduction of 31%.
Embodiment 13
600g methyl-formiate and 252g water to be introduced in autoclave and maintenance 1 hour under 130 DEG C and 25 bar abs.Then inject 538g tri-n-hexyl amine and this mixture is maintained 0.5 hour under 130 DEG C and 25 bar abs.Then introduce other 538g tri-n-hexyl amine in this way and this mixture is maintained 0.5 hour again under 130 DEG C and 25 bar abs.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 16.7 % by weight formic acid, 6.6 % by weight water and 13.6 % by weight methyl alcohol and also has the mixture of 0.08 % by weight carboxylic acid methyl three n-hexyl ammonium.Test conditions and the analytical value chosen are shown in table 3a and 3b.
Compared with embodiment 12, reinforced in workshop section (a2) of tertiary amine is preferably divided into add in sub-workshop section (a2-i) part with add in sub-workshop section (a2-ii) another part make condition identical in other respects under and significantly reduce (being in a ratio of 0.08 % by weight with 0.11 in embodiment 12 % by weight) further in the formation forming carboxylic acid methyl three n-hexyl ammonium under identical amount-in analysis precision-formic acid.Compared with embodiment 11, this corresponds to the relative reduction of 50%.
Embodiment 14
600g methyl-formiate, 252g water and 269g tri-n-hexyl amine to be introduced in autoclave and maintenance 1 hour under 130 DEG C and 25 bar abs.Then inject 403g tri-n-hexyl amine and this mixture is maintained 0.5 hour under 130 DEG C and 25 bar abs.Then introduce other 403g tri-n-hexyl amine in this way and this mixture is maintained 0.5 hour again under 130 DEG C and 25 bar abs.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 16.4 % by weight formic acid, 6.4 % by weight water and 12.7 % by weight methyl alcohol and also has the mixture of 0.10 % by weight carboxylic acid methyl three n-hexyl ammonium.Test conditions and the analytical value chosen are shown in table 4a and 4b.
Embodiment 14 show even when be in 0.1 introducing workshop section (a1) by a small amount of tertiary amine with the mol ratio of the n amine of a1 (introduce)/n (introducing the methyl-formiate of a1) and subsequently the further introducing of amine is divided into sub-workshop section (a2-i) and (a2-ii) time, with as all tertiary amines being introduced in comparative example 11 compared with workshop section (a1), realize the remarkable reduction that carboxylic acid methyl three n-hexyl ammonium (MTHA formate) is formed.Therefore, in embodiment 14, only form 0.10 % by weight MTHA formate, and form 0.16 % by weight in embodiment 11.The value of the 0.10 % by weight MTHA formate obtained in embodiment 14 is even only slight higher than the value in embodiment 13 lower than the value in embodiment 12.The amount of formic acid formed is identical in analysis precision.
Embodiment 15 (temperature is on the impact being formed carboxylic acid methyl three n-hexyl ammonium by three n-hexyl amine when amine being fed in raw material segmentation)
As embodiment 13 carries out embodiment 15, but the temperature of only setting 105 DEG C in sub-workshop section (a2-i) and (a2-ii).The analysis display of reaction output comprises 17.2 % by weight formic acid, 6.5 % by weight water and 13.0 % by weight methyl alcohol and also has the mixture of 0.02 % by weight carboxylic acid methyl three n-hexyl ammonium.
Under condition identical in other respects, the temperature in sub-workshop section (a2-i) and (a2-ii) is down to 105 DEG C by 130 DEG C and the formic acid forming identical amount in analysis precision makes it possible to achieve being formed of carboxylic acid methyl three n-hexyl ammonium (MTHA formate) is significantly reduced to 0.02 % by weight in embodiment 15 further by 0.08 % by weight in embodiment 13.
Embodiment 16-17 (segmentation of being fed in raw material by amine is on the impact being formed carboxylic acid methyl three amyl group ammonium by three amylamines)
Embodiment 16
600g methyl-formiate, 252g water and 910g tri-amylamine to be introduced in autoclave and to maintain 130 DEG C and lower 2 hours of 25 bar abs.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 18.2 % by weight formic acid, 7.6 % by weight water and 13.5 % by weight methyl alcohol and also has the mixture of 0.05 % by weight carboxylic acid methyl three amyl group ammonium.Test conditions and the analytical value chosen are shown in Table 5.
Embodiment 17
600g methyl-formiate and 252g water to be introduced in autoclave and to maintain 130 DEG C and lower 1 hour of 25 bar abs.Then inject 910g tri-amylamine and this mixture is maintained 1 hour again under 130 DEG C and 25 bar abs.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 17.8 % by weight formic acid, 7.4 % by weight water, 13.7 % by weight methyl alcohol and also has the mixture of 0.02 % by weight carboxylic acid methyl three amyl group ammonium.Test conditions and the analytical value chosen are shown in Table 5.
Compared with embodiment 16, due under condition identical in other respects and to form under identical amount (in analysis precision) formic acid in workshop section (a1) methyl-formiate and water and in workshop section (a2) tertiary amine progressively reinforced and form significantly less carboxylic acid methyl three amyl group ammonium (being in a ratio of 0.02 % by weight with 0.05 in embodiment 16 % by weight) according to the present invention.This corresponds to the relative reduction of 60%.
Embodiment 18-19 (segmentation of being fed in raw material by amine is on the impact being formed carboxylic acid methyl three n-octyl ammonium by three n-octylamine)
Embodiment 18
540g methyl-formiate, 227g water and 1273g tri-n-octylamine to be introduced in autoclave and maintenance 2 hours under 130 DEG C and 25 bar abs.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 14.3 % by weight formic acid, 4.4 % by weight water and 10.4 % by weight methyl alcohol and also has the mixture of 0.23 % by weight carboxylic acid methyl three n-octyl ammonium.Test conditions and the analytical value chosen are shown in Table 6.
Embodiment 19
In embodiment 19,339g methyl-formiate, 167g water, 154g formic acid and 107g methyl alcohol to be introduced in autoclave and under 130 DEG C and 25 bar abs, maintain 1 hour together with 1273g tri-n-octylamine.Then autoclave be cooled to room temperature and reduce pressure.Analysis display from the output of autoclave comprises 13.2 % by weight formic acid, 5.3 % by weight water and 13.0 % by weight methyl alcohol and also has the mixture of 0.17 % by weight carboxylic acid methyl three n-octyl ammonium.
The consumption of methyl-formiate, water, formic acid and methyl alcohol corresponds to those that exist in the hydrolysis of 540g methyl-formiate and 227g water after 1 hour under 130 DEG C and 25 bar abs.Therefore, the four kinds of components mentioned are used to be equivalent to workshop section (a1).Workshop section (a2-i) is corresponded to the reaction of three n-octylamine.Test conditions and the analytical value chosen are shown in table 6.
Compared with embodiment 18, owing to progressively to add methyl-formiate under identical amount (in analysis precision) formic acid according to the present invention and water-this is by adding the respective mixtures simulation-of methyl-formiate, water, formic acid and methyl alcohol and progressively adding tertiary amine and form significantly few carboxylic acid methyl three n-hexyl ammonium (being in a ratio of 0.17 % by weight with 0.23 in embodiment 18 % by weight) in workshop section (a2) in workshop section (a1) under condition identical in other respects and being formed.This corresponds to the relative reduction of 26%.
Table 1
Table 2
Table 3a
Table 3b
Mefo: methyl-formiate
THA: three n-hexyl amine
MTHA formate: carboxylic acid methyl three n-hexyl ammonium
Table 4a
Table 4b
Mefo: methyl-formiate
THA: three n-hexyl amine
MTHA formate: carboxylic acid methyl three n-hexyl ammonium
Table 5
Mefo: methyl-formiate
TPA: three amylamines
MTPA formate: carboxylic acid methyl three amyl group ammonium
Table 6

Claims (17)

1. comprise the stream of formic acid and tertiary amine (I) by thermal separation and obtain the method for formic acid, the boiling point that described tertiary amine (I) has under the pressure of 1013hPa abs than the boiling point height at least 5 DEG C of formic acid, wherein
A () produces by merging methyl-formiate, water and tertiary amine (I) liquid stream comprising formic acid, methyl alcohol, water and tertiary amine (I);
B () isolates the methyl alcohol be included in wherein of 10-100 % by weight from the liquid stream obtained by step (a); And
C () is by distillation and take out formic acid from comprising the liquid stream of formic acid, water and tertiary amine (I) of being obtained by step (b) under the pressure of the bottom temp of 100-300 DEG C and 30-3000hPa abs in distillation plant;
Wherein when merge in the step (a) methyl-formiate, water and tertiary amine (I) time,
(a1) in step (a1), introduce methyl-formiate, water and optional tertiary amine (I), the tertiary amine (I) " n (introducing the amine of a1) " wherein optionally introduced in step (a1) makes 0≤n (introducing the amine of a1)/n (introducing the methyl-formiate of a1)≤0.1 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and at the temperature of 50-200 DEG C, set the hydrolysising balance possible under prevailing conditions of 70-100%, and
(a2) then in step (a2), tertiary amine (I) is introduced in the stream obtained in step (a1), the tertiary amine (I) " n (introducing the amine of a2) " be wherein introduced in step (a2) in the stream obtained in step (a1) makes 0.1≤n (introducing the amine of a2)/n (introducing the methyl-formiate of a1)≤2 with the mol ratio of the methyl-formiate " n (introducing the methyl-formiate of a1) " introduced in step (a1), and what make gained mixture react to obtain at the temperature of 50-200 DEG C to mention under (a) comprises formic acid, methyl alcohol, the liquid stream of water and tertiary amine (I),
The total tertiary amine (I) " n (introducing the amine of a) " wherein introduced in step (a) is at least 0.1 with the mol ratio of the total methyl-formiate " n (introducing the methyl-formiate of a) " introduced in step (a).
2. method according to claim 1, the volume that wherein can be used for reaction in step (a1) is 0.1-10 with the ratio that can be used for the volume reacted in step (a2).
3., according to the method for claim 1 or 2, wherein in step (a1), the mol ratio of n (introducing the amine of a1)/n (introducing the methyl-formiate of a1) is 0-0.05.
4. method as claimed in one of claims 1-3, the hydrolysis wherein in step (a1) is carried out at the temperature of 70-150 DEG C.
5. method as claimed in one of claims 1-4, wherein in mol ratio≤1 of the middle n of step (a2) (introducing the amine of a2)/n (introducing the methyl-formiate of a1).
6. method as claimed in one of claims 1-5, the hydrolysis wherein in step (a2) is carried out at the temperature of 70-150 DEG C.
7. method as claimed in one of claims 1-6, wherein introduces tertiary amine (I) in a hierarchical manner in step (a2).
8. method according to claim 7, wherein in step (a2), point 2-100 sub-steps introduces tertiary amine (I).
9. method according to claim 8, that in step (a2), in sub-step, wherein introduces stream n (introducing the amine of a2) total amount is no more than 90%.
10. method according to claim 9, in step (a2), in a sub-steps, wherein introduce the 20-80% of the stream n amine of a2 (introduce) total amount and in sub-step subsequently, introduce the 20-80% of stream n (introducing the amine of a2) total amount, and before described sub-step subsequently, setting the hydrolysising balance possible under prevailing conditions of 70-100%.
11. methods as claimed in one of claims 1-10, wherein select the separation degree in the tertiary amine (I) that is ready to use in step (a) and the distillation plant mentioned in step (c) to make to form two liquid phases in the bottom output of the distillation plant mentioned in from step (c)
D bottom output from the distillation plant mentioned in step (c) is separated into two liquid phases by (), wherein the mol ratio of the formic acid that has of upper phase and tertiary amine (I) is 0-0.5 and the mol ratio of the formic acid that has of lower floor's liquid phase and tertiary amine (I) is 0.5-4;
E () will be recycled in step (a) from the upper phase be separated in step (d); And
F () is recycled to from the lower floor's liquid phase be separated in step (d) in step (b) and/or (c).
12. methods according to claim 11, wherein select the separation degree in the distillation plant mentioned in step (c) to make the mol ratio of formic acid and tertiary amine (I) in the output of described bottom for 0.1-2.0.
13. methods any one of claim 9-12, wherein
(g) under the pressure of the bottom temp of 80-300 DEG C and 1-1000hPa abs in distillation plant by steaming from the lower floor's liquid phase be separated in step (d) except formic acid and tertiary amine (I) and being recycled to steaming the stream removed in one of above-mentioned steps (a)-(f).
14. methods according to claim 13, feeding in step (g) from the lower floor's liquid phase be separated in step (d) wherein by 0.01-50%.
15. methods any one of claim 1-14, are wherein used as tertiary amine (I) by the amine of general formula (Ia):
NR 1R 2R 3(Ia)，
Wherein radicals R 1-R 3identical or different and separately independently of each other for have the non-branching of 1-16 carbon atom or branching, acyclic or ring-type, aliphatic series, araliphatic or aromatic group in each case, wherein single carbon atom can also be selected from the assorted group displacement of-O-and >N-and two or all three groups can also be combined with each other and form the chain comprising at least 4 atoms independently of each other.
16. methods according to claim 15, wherein incite somebody to action wherein radicals R 1-R 3independently selected from C 1-C 12alkyl, C 5-C 8the amine of the general formula (Ia) of cycloalkyl, benzyl and phenyl is used as tertiary amine (I).
17. methods according to claim 16, wherein incite somebody to action wherein radicals R 1-R 3independently selected from C 5-C 8the amine of the general formula (Ia) of alkyl is used as tertiary amine (I).
CN201380061951.3A 2012-11-27 2013-11-12 Method for producing formic acid Pending CN104812731A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP12194451.6 2012-11-27
EP12194451 2012-11-27
PCT/EP2013/073532 WO2014082845A1 (en) 2012-11-27 2013-11-12 Method for producing formic acid

Publications (1)

Publication Number Publication Date
CN104812731A true CN104812731A (en) 2015-07-29

Family

ID=47278682

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201380061951.3A Pending CN104812731A (en) 2012-11-27 2013-11-12 Method for producing formic acid

Country Status (3)

Country Link
EP (1) EP2925715A1 (en)
CN (1) CN104812731A (en)
WO (1) WO2014082845A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114773183A (en) * 2022-04-28 2022-07-22 河北科技大学 Preparation method of methylamine formate ionic liquid

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012000964A1 (en) * 2010-06-29 2012-01-05 Basf Se Method for producing formic acid

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2545658C2 (en) 1975-10-11 1985-12-19 Basf Ag, 6700 Ludwigshafen Process for the production of carboxylic acids from their aqueous solutions
DE2744313A1 (en) 1977-10-01 1979-04-12 Basf Ag PROCESS FOR THE PRODUCTION OF FORM ACID
DE3428319A1 (en) 1984-08-01 1986-02-13 Hüls AG, 4370 Marl Process for the production of anhydrous or largely anhydrous formic acid
DE4211141A1 (en) 1992-04-03 1993-10-07 Basf Ag Process for the preparation of formic acid by thermal cleavage of quaternary ammonium formates
DE102004040789A1 (en) 2004-08-23 2006-03-02 Basf Ag Process for the preparation of formic acid
US8361280B2 (en) 2008-11-24 2013-01-29 Basf Se Process for distillatively obtaining pure 1,3-butadiene from crude 1,3-butadiene

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012000964A1 (en) * 2010-06-29 2012-01-05 Basf Se Method for producing formic acid

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114773183A (en) * 2022-04-28 2022-07-22 河北科技大学 Preparation method of methylamine formate ionic liquid

Also Published As

Publication number Publication date
EP2925715A1 (en) 2015-10-07
WO2014082845A1 (en) 2014-06-05

Similar Documents

Publication Publication Date Title
CN102958894B (en) Method for producing formic acid
US8237005B2 (en) Method for separating and producing cyclohexene
CN110204441A (en) The method for obtaining methylene malonate by the approach of bis- (methylol) malonates
US8350095B2 (en) Method for the production of dimethyl ether
CN102056884A (en) Method for producing C5-aldehyde mixtures having a high n-pentanal content
CN103282338A (en) Method for producing formic acid by reacting carbon dioxide with hydrogen
US11014868B2 (en) Method for producing acetic acid
CN102596878B (en) Process for preparing formic acid by reaction of carbon dioxide with hydrogen
EP2623489B1 (en) Method for producing ditrimethylolpropane
EP1066242A1 (en) Process and apparatus for the production of butylacetate and isobutylacetate
CN107108440A (en) Iodate hydrogen content is reduced in carbonylation method
US8901350B2 (en) Process for the preparation of formic acid
BR112015032389B1 (en) process for the continuous production of light acrylates by esterification of a crude ester grade acrylic acid
CN103080061A (en) Process for preparing formic acid by reaction of carbon dioxide with hydrogen
CN104812731A (en) Method for producing formic acid
CN103998409B (en) Prepare the method for formic acid
US8835683B2 (en) Process for preparing formic acid
US9428438B2 (en) Process for preparing formic acid
CN104024203B (en) The method producing formic acid
WO2008026887A1 (en) Process for preparing dimethyl ether
CN102596972A (en) Method of producing an aminoalkylalkoxysilane
US8889905B2 (en) Process for preparing formic acid
CN108064220B (en) The recycling of acetic acid
AU2016223833B2 (en) Plant and process for producing purified methanol
CN114181111A (en) Synthesis method of m- (p) -alkyl substituted benzonitrile

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C02 Deemed withdrawal of patent application after publication (patent law 2001)
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20150729