CN101896448A - The method for preparing Virahol and 2-butanols by corresponding alkane - Google Patents

Abstract

The present invention relates to a kind of method that is selected from the alcohol (I) of Virahol and 2-butanols by corresponding alkane (II) preparation that is selected from propane and normal butane, described method comprises the steps: A) preparation comprises the feed steam a of alkane (II), B) the feed steam a that will comprise alkane (II) introduces dehydrogenation zone and alkane (II) is carried out dehydrogenation to obtain alkene (III), wherein obtain comprising alkene (III), unreacted alkane (II), optional higher-boiling compound, steam, the product gas flow b of hydrogen and low-boiling compound, C) product gas flow b is compressed at least, with the optional water c1 that is divided into of product gas flow b, comprise alkene (III), the c2 mutually of alkane (II) and optional higher-boiling compound, with the gas phase c3 that comprises hydrogen and low-boiling compound, D) make product gas flow b and/or comprise alkene (III) and the c2 mutually of alkane (II) in esterification zone with paraffinic acid (IV) reaction with 3 or more a plurality of carbon atoms, wherein obtain comprising the corresponding alkyl ester (V) of paraffinic acid and the product mixtures d of unreacted alkane (II), E) the air-flow e1 that will comprise alkane (II) separates from product mixtures d, dehydrogenation zone is returned in optional recirculation, obtains comprising the product mixtures e2 of alkyl ester (V); F) make comprise alkyl ester (V) product mixtures e2 in the ester resolver with water reaction to obtain comprising the product mixtures f of alcohol (I) and paraffinic acid (IV), G) with alcohol (I) with paraffinic acid (IV) is separated from product mixtures f and paraffinic acid chosen wantonly be recycled to esterification zone.

Description

The method for preparing Virahol and 2-butanols by corresponding alkane

The present invention relates to a kind ofly prepare Virahol and prepare the method for 2-butanols by butane by propane.

Alkene water synthol be know and on technical scale, carry out.In industry, carry out two step hydrations, wherein make alkene and sulfuric acid reaction obtain the alkyl sodium sulfate ester, and water obtain pure and mild acid with its hydrolysis in second step.In this method advantageously alkene slightly the form of the mixture of alkene mixture such as alkene, corresponding alkane and other secondary component use.Shortcoming is the highly corrosive medium, and product is subjected to the pollution of the smell formation material of sulfur-bearing, and this may need the loss of the inert paraffins part of other purification step and mixture, and described part is not reacted and discharged after reaction.Other shortcoming is after the alkyl sodium sulfate ester is hydrolyzed into alcohol, must before it is used further in the esterif iotacation step gained dilute sulphuric acid be concentrated.

In addition, with the alkene esterification, subsequently the alkyl ester ester that forms is hydrolyzed into correspondent alcohol with carboxylic acid, recovered acid is known simultaneously.For example, US 4,384, and 148 have described and ethene and acetate reacted obtain ethyl acetate in autoclave.In autoclave, will distill the ethyl acetate of taking out obtains comprising ethyl acetate, ethanol and ether with 1: 5 mol ratio water hydrolysis mixture subsequently.GB 2 238 539 discloses by making the reaction of 1-butylene and trifluoroacetic acid obtain trifluoroacetic acid 2-butyl ester in the presence of peracidity ion exchange resin, subsequently the ester hydrolysis is obtained two step hydrations of 2-butanols.

In addition, industrial carry out alkene on the strongly acidic catalyst on the non-homogeneous carrier such as ion-exchanger, zeolite, heteropolyacid and mineral acid direct one the step hydration.The direct hydration method can be undertaken in gas phase, liquid phase or by the two-phase method.The shortcoming of single stage method is low-conversion and for the high request of used alkene purity particularly.For example propylene must use with the polyacrylic form of grade polymer.

GB-A 2 147 290 has described a kind of method that is prepared Virahol, 2-butanols and methyl tertiary butyl ether by the LPG mixture that comprises propane, normal butane and Trimethylmethane.Gaseous mixture is dehydrogenated to the mixture that comprises propylene, n-butene and iso-butylene, by etherification zone, wherein iso-butylene is obtained methyl tertiary butyl ether with methanol etherification subsequently.Simultaneously will be under selected condition substantially not with the propylene of methyl alcohol reaction and n-butene directly and the water hydration obtain Virahol and 2-butanols respectively.

US 2004/0225165 A discloses a kind of method that is had the alcohol of 3 or more a plurality of carbon atoms by the preparation of corresponding alkane, wherein will comprise propane or more the materials flow of long-chain alkane change into the intermediate stream that comprises corresponding alkene, and intermediate stream is changed into the product materials flow that comprises correspondent alcohol by direct or indirect hydration.As indirect method, described file is mentioned and is made propylene and vitriol oil hydration intermediate formation sulfuric ester, subsequently sulfuric ester is hydrolyzed into two step hydrations of alcohol.The whole bag of tricks of direct hydration has been described in addition.

US 4,484,013 discloses a kind of method for preparing the Virahol and the trimethyl carbinol, wherein will infeed dehydrogenation zone and by the initial air-flow that propane and Trimethylmethane are formed, and promptly not exist dehydrogenation under the air or oxygen to obtain comprising the product gas mixture of propylene, iso-butylene and unconverted propane and Trimethylmethane by non-oxide method.At first, then propane is removed from the product gas flow of dehydrogenation by distillation, wherein made the latter be recycled to dehydrogenation zone low-boiling compound (hydrogen).Substantially the residual gas stream of being made up of propylene, iso-butylene and Trimethylmethane is infeeded the hydration district, wherein propylene is become the Virahol and the trimethyl carbinol with iso-butylene direct hydration on acidic ion exchange resin.At first residual gas stream is divided into the Trimethylmethane materials flow, described Trimethylmethane materials flow is recycled to dehydrogenation zone, is divided into the materials flow that comprises propane and propylene then, and described materials flow was recycled to during propane removes in the past in hydration step.Therefore, the method is characterized in that in hydration and removed unconverted propane in the past, and hydration is used substantially by C ₃And C ₄The initial materials flow that alkene is formed is carried out.

The purpose of this invention is to provide a kind of economically feasible method for preparing Virahol and 2-butanols, described method does not have the shortcoming of prior art.

This purpose is by a kind of method realization for preparing the alkanol (I) that is selected from Virahol and 2-butanols by the corresponding alkane (II) that is selected from propane and normal butane, and described method comprises the steps:

A) provide the initial air-flow a that comprises alkane (II);

B) the initial air-flow a that will comprise alkane (II) infeeds dehydrogenation zone and alkane (II) is dehydrogenated to the product gas flow b of alkene (III) to obtain comprising alkene (III) and unconverted alkane (II), having or do not have higher-boiling compound, steam, hydrogen and low-boiling compound;

C) compressed product air-flow b at least, optional with product gas flow b be divided into water c1, comprise alkene (III) with alkane (II), have or do not have the c2 mutually of higher-boiling compound and comprise hydrogen and the gas phase c3 of low-boiling compound;

D) make product gas flow b or comprise alkene (III) and the c2 mutually of alkane (II) in esterification zone with paraffinic acid (IV) reaction with 3 or more a plurality of carbon atoms to obtain comprising the corresponding alkyl ester (V) of paraffinic acid (IV) and the product mixtures d of unconverted alkane (II);

E) from product mixtures d, take out air-flow e1 and comprise the product mixtures e2 of alkyl ester (V), described air-flow e1 comprise alkane (II) and if the suitable dehydrogenation zone that is recycled to;

F) make the product mixtures e2 that comprises alkyl ester in the ester hydrolysis area, obtain comprising the product mixtures f of alkanol (I) and paraffinic acid (IV) with the water reaction; With

G) alkanol (I) and paraffinic acid (IV) are recycled to esterification zone if taking-up is also suitable from product mixtures f with paraffinic acid.

The inventive method has been saved the highly corrosive vitriolic and has been used.Yet, it should be noted that in addition except that other component (unconverted alkane, rare gas element), only using when comprising the initial air-flow of alkene (III), at esterif iotacation step D with very rare form) in high space time yield of realization and transformation efficiency.Can therefore save and remove the unreacted secondary component in the past in esterif iotacation step.

At first process portion A) in, the initial air-flow a that comprises the alkane (II) that is selected from propane and butane is provided.Under the situation of propane, this materials flow comprises at least 80 volume % propane usually, preferred 90 volume % propane.In addition, it also comprises butane (normal butane, Trimethylmethane), butylene, ethane and ethene usually.The common composition that contains the initial air-flow of propane is disclosed among DE-A 102 46 119 and the DE-A 102 45585.Usually, containing the initial air-flow a of propane is obtained by liquefied petroleum gas (LPG) (LPG).

Under the situation of normal butane as alkane (II), initial air-flow comprises at least 80 volume % normal butanes usually, preferred 90 volume % normal butanes, and in addition, it also comprises ethane, ethene, propane, propylene, Trimethylmethane, butylene and C usually ₅Hydrocarbon.

At a process portion B) in, the initial air-flow that will comprise alkane (II) infeeds the dehydrogenation zone normal catalytic dehydrogenation that works of going forward side by side.In this step, in dehydrogenation reactor, alkane is dehydrogenated to alkene on dehydrogenation activity catalyzer top.In addition, obtain hydrogen and a small amount of low-boiling compound and higher-boiling compound.In the present context, low-boiling compound refers to have than propylene or 1-butylene lower boiling hydrocarbons more; Higher-boiling compound refers to have than propylene or the more high boiling hydrocarbon of 2-butylene.The low-boiling compound that for example obtains in dehydrogenating propane can be methane, ethane and ethene, and higher-boiling compound is C ₄ ⁺Hydrocarbon (normal butane, Trimethylmethane, butylene, divinyl).In the normal butane dehydrogenation, the low-boiling compound that obtains can for example be methane, ethane and ethene, propane and propylene, and higher-boiling compound is C ₅ ⁺Hydrocarbon.In addition, if dehydrogenation, is generally oxycarbide (CO, CO at oxygen-containing gas ₂), CO especially ₂Existence under carry out, then in the product gas mixture of dehydrogenation, obtain steam, have or do not have small amounts of inert gas.The product gas flow of dehydrogenation comprises steam usually, described steam added in the dehydrogenation gaseous mixture and/or-situation of (oxidation or non-oxide) dehydrogenation in the presence of oxygen under-in dehydrogenation, form.When dehydrogenation is carried out in the presence of oxygen, rare gas element (nitrogen) is introduced in the dehydrogenation zone, unless infeed purity oxygen with the oxygen flow that infeeds.In addition, unconverted alkane (II) (propane and/or normal butane) is present in the reaction gas mixtures.

The alkane dehydrogenation can be carried out in known all type of reactor of prior art in principle.The description quite comprehensively of the type of reactor that is suitable for according to the present invention also be present in "

StudiesDivision, oxydehydrogenation and selectable method of dehydrogenating " in (Study Number 4192 OD, 1993,430 Ferguson Drive, Mountain View, California, 94043-5272, the U.S.).

Dehydrogenation can be used as oxidation or non-oxide hydrogenation is carried out.But dehydrogenation isothermal or adiabatic carrying out.Dehydrogenation can be carried out in fixed-bed reactor, moving-burden bed reactor or fluidized-bed reactor in catalysis.

The preferred self-heating of non-oxide catalysis alkane dehydrogenation is carried out.For this reason, in first reaction zone, in addition oxygen is sneaked in the reaction gas mixtures of dehydrogenation, be present in hydrogen and/or hydrocarbon partial combustion at least in the reaction gas mixtures, this directly produces at least some dehydrogenation heat that need at least one reaction zone in reaction gas mixtures.

Compare with method for oxidation, one of non-oxide method is characterized as intermediate formation hydrogen at least, and the existence of hydrogen has proved this point in the product gas of dehydrogenation.In oxydehydrogenation, in the product gas of dehydrogenation, do not find free hydrogen.

The reactor types that is fit to is for solidifying bed tubular type or tube bundle reactor.In these reactors, catalyzer (if dehydrogenation catalyst and suitable special-purpose oxide catalyst) is configured in reaction tubes or the reaction tubes tube bank as fixed bed.The popular response bore is about 10-15cm.Typical dehydrogenation tube bundle reactor contains 300-1000 the reaction tubes of having an appointment.Internal temperature in the reaction tubes in 300-1200 ℃ of scope, preferably changes in 500-1000 ℃ of scope usually.For the propane or butane dehydrogenation of Phillips Petroleum Co., working pressure is generally the 0.5-8 crust when using low steam to dilute, usually being the 1-2 crust, is 3-8 crust (corresponding to steam activation reforming method (STAR method) or Linde method) when using high steam to dilute maybe.Common gas space-time speed (GHSV) is 500-2000h based on used hydrocarbon ^-1The catalyzer geometrical shape can for example be spherical or cylindrical (hollow or solid).Also can move mutual a plurality of fixed-bed tube reactors or tube bundle reactor side by side, wherein at least one alternately is a reproduced state.

Non-oxide catalytic self-heating dehydrogenation also can be carried out under heterogeneous catalysis in fluidized-bed according to Snamprogetti/Yarsintez FBD method, suitably, two fluidized-bed parallel runnings, one of them is generally reproduced state.Working pressure is generally the 1-2 crust, and desorption temperature is generally 550-600 ℃.The required heat of dehydrogenation can be introduced in the reactive system by dehydrogenation catalyst being preheated to temperature of reaction.Oxygenous co-fed (cofeed) of hybrid packet makes and save preheater and required heat directly produces in the burning in the presence of the oxygen by hydrogen and/or hydrocarbon in reactor assembly.If suitable, but additionally mixed comprises the co-fed of hydrogen.

Non-oxide catalytic self-heating dehydrogenation is preferably carried out in the column plate reactor.This reactor contains one or more successive catalyst beds.The number of catalyst bed can be 1-20, and advantageously 1-6, preferred 1-4, particularly 1-3.Preferred reactant gas radially or axially flows through catalyst bed.Common this column plate reactor stagnant catalyst bed operating.Under the simplest situation, stationary catalyst bed is in shaft furnace reactor or axially configuration in the annular die gap of concentric cylindrical grid.The shaft furnace reactor is corresponding to a column plate.In independent shaft furnace reactor, carry out dehydrogenation corresponding to an embodiment.In other embodiment preferred, dehydrogenation is carried out in having the column plate reactor of 3 catalyst beds.

Usually the amount that adds the oxygen-containing gas in the reaction gas mixtures is selected by this way: the required heat of alkane (propane and/or normal butane) dehydrogenation produces with the carbon burning that is present in any hydrocarbon in the reaction gas mixtures and/or exist with the coke form by the hydrogen that is present in the reaction gas mixtures.Usually, the total amount of the oxygen of supplying with based on the propane total amount is the 0.001-0.5 moles/mole, preferred 0.005-0.25 moles/mole, more preferably 0.05-0.25 moles/mole.Oxygen can pure oxygen form or use with the form of the oxygen-containing gas that comprises rare gas element.For preventing high propane and the propylene loss in the aftertreatment (seeing below), high and be at least 50 volume % when the oxygen level of used oxygen-containing gas, preferred at least 80 volume % may be favourable during at least 90 volume % more preferably.Particularly preferred oxygen-containing gas is O ₂Content is the oxygen of the technical grade purity of about 99 volume %.In addition, wherein air-supplied method as oxygen-containing gas also is possible.

The hydrogen that burning produces heat adds any hydrogen in the reaction gas mixtures in addition for the hydrogen that forms and as hydrogen-containing gas in the dehydrogenation of catalysis alkane.The amount of hydrogen just should preferably make the H in the reaction gas mixtures after infeeding oxygen ₂/ O ₂Mol ratio is the 1-10 moles/mole, preferred 2-5 moles/mole.In staged reactor, this is applicable to the each intermediate feed that contains oxygen and any hydrogen-containing gas.Make the hydrogen catalysis burning.Also catalytic hydrocarbon and the burning of oxygen and the burning of hydrogen and oxygen usually of used dehydrogenation catalyst makes in addition to need not special oxide catalyst in principle.In one embodiment, operate under the existence of one or more oxide catalysts and carry out, the hydrogen catalyzed burning with oxygen of described oxide catalyst selectivity in the presence of hydrocarbon.These hydrocarbon and oxygen combustion obtain CO, CO ₂Therefore only proceed to less degree with water.Dehydrogenation catalyst preferably is present in the different reaction zones with oxide catalyst.

In being reflected at more than a step when carrying out, oxide catalyst can exist only in one, more than in one or all reaction zones.

The catalyzer of preferably that selectivity is hydrogen catalyzed oxidation is configured in that oxygen partial pressure is higher than on the point of other point in the reactor, particularly near the feed points of oxygen-containing gas.Oxygen-containing gas and/hydrogen-containing gas can infeed on one or more points in reactor.

In an embodiment of the inventive method, there is the intermediate feed of oxygen-containing gas and hydrogen-containing gas in each column plate upstream of column plate reactor.In other embodiment of the inventive method, oxygen-containing gas and hydrogen-containing gas are infeeded each column plate upstream except that first column plate.In one embodiment, special layer of oxidation catalyst is present in the downstream of each feed points, is dehydrogenation catalyst layer afterwards.In other embodiments, there is not special oxide catalyst.Desorption temperature is generally 400-1100 ℃; Pressure in last catalyst bed of column plate reactor is generally the 0.2-5 crust, preferred 1-3 crust.GHSV (gas space-time speed) is generally 500-2000h ^-1, and in high load operation even up to 100000h ^-1, preferred 4000-16000h ^-1

The hydrogen catalyzed incendiary preferred catalyst of selectivity comprises and is selected from germanium, tin, lead, arsenic, antimony and bismuth oxide compound and/or phosphatic oxide compound and/or phosphoric acid salt.Other preferred catalyst of hydrogen catalyzed incendiary comprises the precious metal and/or the I family of periodictable transition group VIII.

Used dehydrogenation catalyst has carrier and active composition usually.Carrier is made up of refractory oxides or mixed oxide usually.Dehydrogenation catalyst preferably comprise be selected from zirconium dioxide, zinc oxide, aluminum oxide, silicon-dioxide, titanium dioxide, magnesium oxide, lanthanum trioxide, cerium oxide and composition thereof metal oxide as carrier.Mixture can for physical mixture or chemical mixing mutually as magnalium oxide compound or Zinc-aluminium mixed oxide.Preferred carrier is zirconium dioxide and/or silicon-dioxide; The mixture of preferred especially zirconium dioxide and silicon-dioxide.

The active composition of dehydrogenation catalyst comprises the element of one or more transition group VIII usually, preferred platinum and/or palladium, more preferably platinum.In addition, dehydrogenation catalyst can comprise the element of one or more main group I and/or II, preferred potassium and/or caesium.Dehydrogenation catalyst can comprise one or more elements that comprises the transition group III of lanthanon and actinide elements in addition, preferred lanthanum and/or cerium.At last, dehydrogenation catalyst can comprise the element of one or more main group III and/or IV, and preferably one or more are from boron, gallium, silicon, germanium, tin and plumbous element, more preferably tin.

In preferred embodiments, dehydrogenation catalyst comprises the element and at least a element that comprises the transition group III of lanthanon and actinide elements of the element of the element of at least a transition group VIII, at least a main group I and/or II, at least a main group III and/or IV.

For example, can use WO 99/46039, US 4 according to the present invention, 788,371, EP-A 705 136, WO 99/29420, US 5,220,091, US 5,430,220, US 5,877, and 369, EP 0 117 146, DE-A 199 37 106, DE-A 199 37 105 and DE-A 199 37 107 disclosed all dehydrogenation catalysts.The particularly preferred catalyzer that is used for above-mentioned self-heating dehydrogenating propane variation scheme is according to the embodiment 1,2,3 of DE-A199 37 107 and 4 catalyzer.

Preferably in the presence of steam, carry out the dehydrogenation of self-heating alkane.The steam that adds is as the gasification of organic sediments on thermal barrier and the support catalyst, and it stops the carbonization of catalyzer and improves life of catalyst.This is converted into carbon monoxide, carbonic acid gas and water in some cases with organic sediments.

Dehydrogenation catalyst can be regenerated in a manner known way.For example, steam can be added the gas that comprises oxygen is burnt by catalyst bed and with sedimentary carbon often at elevated temperatures.Make balance shift to the product of dehydrogenation with the steam dilution.After the regeneration, if suitable catalyzer is reduced with hydrogen-containing gas.

In by the self-heating dehydrogenating propane that infeeds basic pure oxygen, had the gaseous mixture of following composition usually: 10-45 volume % propane, 5-40 volume % propylene, 0-5 volume % methane, ethane, ethene and C ₄ ⁺Hydrocarbon, 0-5 volume % carbonic acid gas, 0-20 volume % steam and 0-25 volume % hydrogen and 0-5 volume % rare gas element.

In by the self-heating butane dehydrogenation that infeeds basic pure oxygen, had the gaseous mixture of following composition usually: 5-40 volume % butane, 10-60 volume %1-butylene and 2-butylene, 0-10 volume % methane, ethane, ethene, propane, propylene and C ₅ ⁺Hydrocarbon, 0-5 volume % carbonic acid gas, 0-20 volume % steam, 0-25 volume % hydrogen and 0-5 volume % rare gas element.

When it left dehydrogenation zone, product gas flow b under the pressure of preferred 1.5-3 crust, and had 400-700 ℃ temperature usually at the 1-5 crust.

Product gas flow b can be divided into two son streams, at this moment, a sub-stream be recycled to the self-heating dehydrogenation, corresponding to DE-A 102 11 275 and DE-A 100 28 582 described recycle gas methods.

At process portion C) in, compressed product air-flow b.The compression of product gas flow b proceeds to the 5-150 crust, preferred 15-100 crust, the more preferably pressure of 20-60 crust.Compression can have a plurality of steps of intercooling step, for example carries out in three or four steps; It for example carries out in three steps preferably in a plurality of steps.In an embodiment of the inventive method, in one or two step, product gas flow b is compressed to the pressure of 5-12 crust, in one or two step, be compressed to the pressure of 10-25 crust then.Cooling also can be carried out in a plurality of steps, preferably carries out in a plurality of steps.Used refrigerant comprises air, river or cold water and the pressure by being compressed at the most 20 crust in the air-cooler and refrigerant such as ethene, propylene and the propane of the temperature that is cooled to-40 ℃ to-100 ℃ of reducing pressure subsequently.

Optional with product gas flow b be divided into water c1, the hydrocarbon phase c2 of comprise alkene (III) and unconverted alkane (II) and comprise hydrogen and the gas phase c3 of low-boiling compound.When product gas flow b comprises steam, usually at processing step C) in remove step.Yet, also can only carry out water and remove (seeing below).

Can at first from product gas flow b, remove and anhydrate.If removing of water can be undertaken by condensation, cooling and suitable compressed product air-flow b, and if can in one or more cooling steps and suitable compression step, carry out.For this reason, usually product gas flow b is cooled to 30-80 ℃, preferred 40-65 ℃ temperature.Condensation can and/or be carried out as intercooling in compression step before compression.

In an embodiment of the inventive method, guiding product gas flow b is by one group of interchanger and therefore at first be cooled to 50-200 ℃ temperature, further is cooled to 40-80 ℃ at the quench tower water then, for example 55 ℃ temperature.This condensation goes out most of steam and is present in some higher-boiling compounds among the product gas flow b.Under the situation of dehydrogenating propane, these can be C ₄ ⁺Hydrocarbon, especially C ₅ ⁺Hydrocarbon.

This provides poor vapoury product gas flow b.It still comprises 5 volume % steam at the most usually.Anhydrate for from product gas flow b, removing substantially fully, the drying step by molecular sieve can be provided.

When carrying out the dehydrogenation of self-heating alkane as oxygen-containing gas by the air that infeeds pure oxygen or be rich in oxygen, can be with product gas flow b aftertreatment, also can as described belowly obtain containing alkane-and the mixture c2 of alkene.

Subsequently, comprise the liquid hydrocarbonaceous streams c2 of propane and propylene and/or normal butane and butylene to stay the residual vaporous stream c3 that comprises hydrogen and low-boiling compound with product gas flow b cooling and by the condensation taking-up.Under the situation of dehydrogenating propane, hydrocarbon flow c2 can comprise methane, ethane, ethene and C in addition ₄ ⁺Hydrocarbon; It comprises a small amount of at least ethane and ethene usually.Also can select to remove among the compression step C alkane and the alkene that the temperature and pressure in the step makes major part be present among the product gas flow b is present among the air-flow c3.As hydrocarbon flow c2, this air-flow c3 can be guided to esterification zone D or as selecting in the absorption step (as described below).

Under the situation of normal butane dehydrogenation, selection condition makes to have very much overwhelmingly normal butane and butylene condensation are gone out.Except that hydrogen, residual vaporous stream c3 also comprises methane and carbon monoxide usually as low-boiling compound.In addition, if it also can comprise ethane and ethene and-do not carry out self-heating dehydrogenation-especially nitrogen and rare gas (mainly being argon gas) by infeeding pure oxygen.It also can comprise C in addition ₃-C ₄Hydrocarbon.For this reason, usually product gas flow b is compressed to the pressure of 5-60 crust and be cooled to-10 ℃ to-60 ℃ temperature.

Hydrocarbon flow c2 not only, cooling and compression are also condensable to go out water c1, anhydrates if remove fully from product gas flow b in the past at condensing steps, then can be with described water by in phase separator, being separated from C ₃Remove among the hydrocarbon phase c2.Under the situation of multistep cooling and compression, the condensation product materials flow that all can be obtained infeeds in the phase separator.

Also can be at C ₃Hydrocarbon phase c2 condensation was saved in the past to remove from product gas flow b and was anhydrated.At this moment, water condenses with the hydrocarbon phase c2 that contains alkane and alkene as water c1.Subsequently water is separated in phase separator with hydrocarbon phase then.

Usually, product gas flow is cooled off with refrigerant by interchanger.Cooling can use a plurality of cooling loops to carry out in several steps.Cooling can be carried out in tower in several steps, at this moment, takes out the gas that rises in the tower, cooling, and (part) condensation also is recycled in the tower.Condensation product is taken out in bottom at tower, and takes out the uncondensed gas that does not have condensation in the highest cooling loop or at the top of tower.

When the alkane dehydrogenation is carried out as the self-heating dehydrogenation, during the combustion of hydrogen that forms simultaneously, the result is the low hydrogen content of product gas flow b.Therefore, removing step C) if in-carry out it-can having very much overwhelmingly, condensation goes out C ₃And/or C ₄Hydrocarbon, and only discharge the very C of small portion with the waste gas materials flow c3 that comprises hydrogen/low-boiling compound ₃And/or C ₄Hydrocarbon.

Can carbonic acid gas be removed from product gas flow b to obtain poor carbonated product gas flow b by gas scrubbing before the hydrocarbon condensation carrying out.Can be independent combustion step before the carbon dioxide washing, wherein co selective oxidation is become carbonic acid gas.

For CO ₂Remove, used washings is generally sodium hydroxide solution, potassium hydroxide solution or chain triacontanol amine solution; The preferred activation N methyldiethanol amine solution that uses.Usually, carrying out before the gas scrubbing, product gas flow c is being compressed to the pressure of 5-25 crust by single step or multistep compression.

Can obtain CO ₂Content is generally＜100ppm or even＜the poor carbonated product gas flow b of 10ppm.

At cooling and condensing steps C) in the liquid hydrocarbonaceous condensate materials flow c2 that obtains comprise 20-60 mole % alkane (II), 20-60 mole % alkene (III), 0-20 mole % low-boiling compound and 0-5 mole % higher-boiling compound usually.

Under the situation of dehydrogenating propane, at cooling and condensing steps C) in the liquid hydrocarbonaceous condensate materials flow c2 that obtains can comprise 20-70 mole % propane, 20-60 mole % propylene, 0-10 mole % methane, 0-10 mole % ethane and ethene and 0-5 mole %C ₄ ⁺Hydrocarbon.

When by air-supplied when carrying out the dehydrogenation of self-heating alkane, can and also can as described belowly obtain containing the mixture c2 of alkane and alkene with product gas flow b aftertreatment as oxygen-containing gas.If at first it obtains poor vapoury product gas flow b and removes devaporation by condensation, cooled product air-flow b and suitable compression.Subsequently by product gas flow b is contacted with the inertia absorption agent, desorb is dissolved in alkane in the inertia absorption agent and alkene and will takes out to obtain gaseous state C in alkane and the never condensable or lower boiling gaseous fraction of alkene then ₃And/or C ₄Hydrocarbon flow, and remove and comprise hydrogen and low-boiling compound (under the situation of dehydrogenating propane, methane, ethane, ethene, nitrogen, carbon monoxide, carbonic acid gas have or do not have oxygen and have or do not have rare gas element; Under the situation of normal butane dehydrogenation, also have propane and propylene in addition) waste gas materials flow c3.Under the situation of self-heating alkane dehydrogenation, the aftertreatment of described product gas flow b also can correspondingly be carried out as oxygen-containing gas by the air that infeeds pure oxygen and/or be rich in oxygen.

For this reason, air-flow b is clung in absorption step at 5-40, preferred 8-20 crust, more preferably the 10-15 crust contacts with the inertia absorption agent down, and it absorbs C in the inertia absorption agent ₃And/or C ₄Hydrocarbon and a small amount of C ₂Hydrocarbon also provides load that C is arranged ₃And/or C ₄The absorption agent of hydrocarbon and the waste gas c3 that comprises the residual gas component.These are essentially oxycarbide, hydrogen, rare gas element and C ₂Hydrocarbon and methane.Very incomplete owing to removing usually, small amounts of propane and propylene and/or C ₄Hydrocarbon also can still be present among the materials flow c3.In desorption procedure, C ₃And/or C ₄Hydrocarbon is once more by discharging in the absorption agent.

The inertia absorption agent that is used for absorption step is generally the high boiling point non-polar solvent, C to be removed ₃And/or C ₄Hydrocarbon mixture has therein than residue waits to remove significantly better solubleness of gaseous fraction.Absorption can be undertaken by absorption agent simply by making materials flow c.It also can carry out in tower.Also stream, adverse current or cross-flow are carried out for it.The absorption tower that is fit to for example for having the tray column of bubble deck, valve tray and/or sieve plate, has structured packing, and for example specific surface area is 100-1000m ²/ m ³Fabric filler or the metal sheet filler as

The tower of 250Y and have random packing for example has ball, ring or the saddle made by metal, plastics or the pottery tower as random packing.Yet drip and spray column, graphite block resorber, surface absorber such as thick film resorber and film absorption device and the bubble-plate column that has and do not have an internals also are useful.

The absorption tower preferably has absorber portion and rectifying section.For improving C in the solvent in the rectifying mode ₃And/or C ₄The enrichment of hydrocarbon then can be introduced heat at the bottom of the tower.As selection, stripping gas can be infeeded at the bottom of the tower, for example nitrogen, air, steam or propane/propylene mixtures.For example, the load absorption agent contacts with the stripping air-flow in the rectifying section on absorption tower.This stripping from the load absorption agent goes out C ₂Hydrocarbon.Can be with a part of top product condensation and the top of drawing back tower as backflow with the restriction solvent loss.

The absorption agent that is fit to is relative non-polar organic solvent, for example aliphatic C ₄-C ₁₈Alkene, petroleum naphtha or aromatic hydrocarbons be as from oil distillate in the paraffin distillatory, or have the ether of macoradical, or the mixture of these solvents, can be to wherein adding polar solvent such as phthalic acid 1,2-dimethyl ester.The absorption agent that is fit to also has phenylformic acid and phthalic acid and straight chain C ₁-C ₈The ester of alkanol, as the positive butyl ester of phenylformic acid, methyl benzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate, and so-called heat medium oil such as biphenyl and phenyl ether, its chlorine derivative and triaryl alkene.The absorption agent that is fit to is the mixture of biphenyl and phenyl ether, is preferably Azeotrope compositions, and is for example commercially available

This solvent mixture usually comprises 0.1-25 weight % dimethyl phthalate.The absorption agent that is fit to also has butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, the tetradecane, pentadecane, n-Hexadecane, heptadecane and octadecane, or by obtaining in the refinery materials flow and comprising the cut of described linear alkane as main ingredient.Preferred absorption agent is C ₈-C ₁₀Hydrocarbon; Preferred especially C ₉Hydrocarbon, especially nonane.

For desorb C ₃And/or C ₄Hydrocarbon is with the heating of the absorption agent of load and/or be decompressed to lower pressure.As selection, desorb also can be by carrying out with steam stripped or with decompression, heating and steam stripped combination in one or more processing steps usually.For example, desorb can be carried out in two steps, and at this moment, second desorption procedure is carried out under than the lower pressure of first desorption procedure and the desorption gas of second step is recycled in the absorption step.Regenerated absorption agent in the desorption procedure is recycled to absorption step.If suitable, this may be comprised C ₄ ⁺Part discharge, aftertreatment and the recirculation of the absorption agent materials flow of hydrocarbon, or abandon.

In a process variant, desorption procedure is undertaken by decompression and/or heating load absorption agent.In other process variant, carry out stripping with steam in addition.

Removing is not very complete usually, makes to depend on the type of removing, at C ₃And/or C ₄Still can exist a small amount of in the hydrocarbon flow or even trace other gaseous fraction, especially low boiling hydrocarbon only.

Subsequently, can be with the C of desorb ₃And/or C ₄The hydrocarbon flow cooling, can additionally compress it this moment in one or more other compression steps.This provides by C ₃And/or C ₄The condenses streams c2 that hydrocarbon is formed.Materials flow c2 also can comprise a small amount of C ₂Hydrocarbon.In addition, can obtain the aqueous condensate materials flow and the waste gas materials flow c3 of other amount in some cases.When passing through, obtain the aqueous condensate materials flow usually with steam stripped desorb dissolved gases.

Compression can be carried out in one or more steps successively.Usually compression is generally by the 1-29 crust, and the pressure of preferred 1-10 crust proceeds to the pressure of 12-30 crust.After each compression step is cooling step, wherein air-flow is cooled to 15-80 ℃, preferred 15-60 ℃ temperature.Gaseous mixture with compression is cooled to-10 ℃ to 60 ℃ subsequently, preferred-10 ℃ to 30 ℃ temperature.Can be from liquid C in device for phase saparation ₃And/or C ₄Remove the aqueous condensate materials flow of any existence in the hydrocarbon flow.

Above-mentioned absorption step also can followingly be carried out:

In the absorption tower used absorption agent be in esterification zone with the same chain alkanoic acid of corresponding chain alkene reaction.At this moment, can save above-mentioned desorption procedure.Load has C ₃And/or C ₄The absorption agent of hydrocarbon if promptly this moment, paraffinic acid can be suitably in after further heating and/or the compression then, directly guides in the esterification zone.At this moment, the absorption agent charging that is used for the absorption tower can be the paraffinic acid of removing the step (G) of removing from ester hydrolysis area downstream.At this moment, this organic acid is not directly recycled to esterification zone, but to absorption step and load C therefrom ₃And/or C ₄Hydrocarbon is to esterification zone.

Can but must not carry out process portion C) in remove step.As mentioned above, but always carry out the compression of product gas flow b at least.For example, if, in the presence of steam, do not carry out the alkane dehydrogenation, then gained dehydrogenation gaseous mixture b can not carried out C not by infeeding oxygen-containing gas yet ₃And/or C ₄Removing of hydrocarbon and directly infeed in the esterification zone, and contact with organic acid, wherein said gaseous mixture b, under the situation of dehydrogenating propane, substantially form by propane, propylene, hydrogen and low-boiling compound, under the situation of normal butane dehydrogenation, form by butane, 1-butylene, 2-butylene, hydrogen and low-boiling compound substantially.When product gas flow b comprises steam,, remove devaporation-separately for example as above at C because dehydrogenation undertaken by infeeding oxygen and/or infeeding steam) described down by condensation-may be enough, and can make and comprise C ₃And/or C ₄The remaining mixture of hydrocarbon, hydrogen and low-boiling compound is with gas or liquid form and organic acid reaction.Esterification is not substantially disturbed in the existence of oxycarbide and other rare gas element (nitrogen in the atmosphere) yet.

Residual vaporous stream c3 can and preferably mainly be recycled to dehydrogenation step A) in.From described method, remove and discharge son stream to prevent the secondary component enrichment.This son stream can be burned or delivers in the processing step of alkane/alkene that recovery wherein exists.Recovery can be used as and absorbs or absorption, carries out as membrane sepn or rectifying.

Also the sub-stream of residual vaporous stream c3 can be delivered to esterif iotacation step D) in.

Hydrocarbon phase c2 directly or after further pressure improves can be infeeded esterif iotacation step D).Aqueous condensate materials flow c1 can be discharged or guides to ester hydrolysing step (process portion F) from described method).

At processing step D) in, if make product gas flow b or-at operation stage C) in carry out separating step-comprise alkane (II) with alkene (III) if c2 mutually and suitable residual vaporous stream c3, if or carry out absorption step with organic acid as mentioned above, load has C ₃And/or C ₄The paraffinic acid of hydrocarbon (IV) and paraffinic acid (IV) react the corresponding alkyl ester (V) (isopropyl esters and/or 2-butyl ester) that obtains comprising paraffinic acid (IV) and the product gas mixture d of unconverted alkane (II) in esterification zone.

Esterification can be carried out in liquid phase or as gas/liquid reactions two-phase (relevant with reactant).

Esterification is carried out under the temperature of the pressure of 10-100 crust and 50-250 ℃ usually.Based on alkene, paraffinic acid (IV) is generally with the amount of 0.5-50 moles/mole alkene, and is preferably excessive with stoichiometry, and preferably with 1.1-6 moles/mole alkene, more preferably the amount of 1.2-2.5 moles/mole alkene is used.Usually make 50-90% chain alkene reaction obtain corresponding alkyl ester.In addition, can make the unsaturated secondary component reaction that is present among product gas flow b and/or the materials flow c2 obtain alkyl ester.These can be removed by distilling directly in post-processing step thereafter.Be present in alkane among materials flow b and/or the c2 according to their character at esterif iotacation step D) in do not react, and at esterif iotacation step D) under the situation of in even liquid phase, carrying out in materials flow d in esterification unconverted alkene (III), or carrying out esterif iotacation step D with the gas-liquid pattern) situation under leave esterif iotacation step D as other materials flow d2).Except that alkane and alkene, this materials flow also comprises the ester and the water of a small amount of formation and has been present in low-boiling compound among the materials flow c2.

Esterif iotacation step D) carry out with the gas-liquid pattern, it can contain two districts, reaction zone and washing section again.The purpose of reaction zone is the maximum conversion rate of paraffinic acid (IV) and alkene (III).In washing section again, the sour resistates among the air-flow d2 has been removed in the adding of water largely.This makes has avoided as materials flow d2) etching problem of other device in partly during recirculation.

Esterification can the drip pattern be carried out in the fixed bed reaction district or with fluid bed mode.In principle, also stream or adverse current and cross-flow guide organic acid and the materials flow that contains alkene.Preferably a plurality of catalyst beds are connected into one group, if suitable centre infeeds acid and/or contains the materials flow of alkene.The preferred 2-5 that uses is individual, the group in preferred 2-3 differential responses district.The reaction heat that discharges can be removed by inner heat exchange surface.A kind of method with external circulating system also is possible, and the interchanger that is used to remove reaction heat wherein is installed.The adjustment of cycle rate makes the axial temperature of adjusting substantially on demand in the reactor distribute.As selection, esterification also can be carried out in bubble-plate column or spray circuits reactor.Specific embodiments is the tubular reactor of fluid bed mode, and described reactor with controllable manner operation (so-called floating bed method), has one group of external heat exchanger and two reactor at the point of fluidization of catalyzer.

In washing section again, the adding of water removes the disacidify resistates.Aspect equipment, this district designs or is integrated into absorption tower in the fixed-bed reactor separately corresponding to can be used as specific equipment.Used internals can be column plate, structured packing or random packing.Select the amount of washing water to make sour resistates amount＜50ppm among the air-flow d2, preferred＜＜10ppm, more preferably＜＜1ppm.In order to obtain＜acid of 1ppm, the amount of washing water: the common ratio of the amount of acid to be removed is 1-20kg/kg.Load has the washing water of sour resistates can be at processing step F) in be used for the ester hydrolysis.

The heterogeneous esterification catalyst that is fit to is an acidic ion exchange resin, especially by form with the sulfonated polystyrene of divinyl benzene crosslinked those.These catalyzer can have different pore structure-differences at micropore, gel-type and macroporous catalyst.Electronegative group such as chlorine or fluorine also can be combined on the aromatic ring of polystyrene.This class catalyzer that is fit to for example is Amberlyst 15,16,36,39,40,46,48,70,119,139, Lewatit K1131, K1221, K1461, K2420, K2629, K2649, Purolite CT169, CT175, CT275, Diaion RCP145H.Especially preferably contain those catalyzer of the acid group of high-content, for example Amberlyst 35,36,40,49,119, Lewatit K2649, Purolite CT275.The catalyzer that the present invention mentioned can be done usually or moisture form obtains.Two kinds of forms all are fit to; Under the situation of aqueous catalyst, by with organic acid or with alcohol, preferred Virahol or 2-butanols washing replacing water.The one group of catalyzer that relates to acidic ion exchange resin is derived from sulfonation polycondensation aromatic substance or graphite carbon.This material is for example by forming polynuclear aromatic compound such as naphthalene or anthracene sulfonation under the condition that causes the aromatic substance condensation.Similar approach comes from organic materials such as sugar carbonization under anoxia condition.Then with corresponding resistates sulfonation.Another organizes organic heterogeneous catalyst derived from being adsorbed on the ionic liquid that is fit on the solid support material.Except that the polymerization plasma exchange resin, the catalyzer that is fit to also has a series of organic catalysts such as acidic metal oxide catalyzer or acid zeolite.The acidic metal oxide catalyzer is particularly including sulfated zirconia and wolframic acid zirconium and/or wolframic acid titanium system.This group catalyzer also comprises heteropolyacid such as tungsten-or the water-insoluble acid-salt of molybdophosphate or tungstosilicic acid.This insoluble salt is by these acid and metallic cation such as K with heavy ion radius ⁺, Rb ⁺, Cs ⁺, NH ₄ ⁺Or Ag ⁺Form.In these salt, common 10-90 mole %, particularly 40-85 mole % acidic site is exchanged by positively charged ion.Another group catalyzer is derived from the heteropolyacid or its salt that are adsorbed on inert support material such as silica gel, aluminum oxide or the gac.The zeolite catalyst that is fit to comprises those of beta-zeolite, faujusite, mordenite and ZSM-5 zeolite structure type.Except that zeolite structured, the ratio (coefficient) of zeolite structured middle Si/Al atom is most important for the catalytic activity of zeolite.The zeolite that is suitable for the inventive method is that coefficient is 2-500, particularly 3-200, most preferably those of 5-100.The common thermal activation of organic catalyst of the present invention is about to material at 50-900 ℃, preferred 90-500 ℃ temperature lower calcination.

Esterification also can be carried out under homogeneous catalysis.The catalyzer that is suitable for this purpose is mineral acid, especially sulfuric acid, sulfonic acid or free heteropolyacid and their acid soluble salt or acidic ion liquid.

Preferably esterification in the presence of heterogeneous catalyst.Preferred heterogeneous catalyst is an acidic ion exchange resin, acid potassium, caesium or the ammonium salt of heteropolyacid and beta-zeolite and faujusite.Special preferred ion exchange resin.

Preferred paraffinic acid (IV) is non-branching or branching C ₄-C ₁₀Paraffinic acid; Preferred especially non-branching or branching C ₄-C ₆Paraffinic acid; Very particularly preferably butyric acid (butane acid), valeric acid (pentane acid) and isovaleric acid (acid of 3-methylbutane).For example the reaction of propylene and butyric acid obtains isopropyl butyrate, obtains isopropyl isovalerate and isopropyl isovalerate respectively with valeric acid and isovaleric acid reaction.1-butylene and 2-butylene and butyric acid reaction obtain butyric acid 2-butyl ester, obtain valeric acid 2-butyl ester and isovaleric acid 2-butyl ester respectively with valeric acid and isovaleric acid reaction.

At processing step E) in, the air-flow e1 that will comprise unconverted alkane (II) (propane and/or normal butane) removes from the product mixtures d of esterification, and if the suitable dehydrogenation zone that is recycled to.For this reason, usually with the product mixtures d decompression of esterification to remove the air-flow e1 that comprises propane and/or normal butane and to obtain comprising the product mixtures e2 of alkyl ester (V).Air-flow e1 can be in process portion D again the air-flow d2 of washing section in conjunction with and they can be infeeded dehydrogenation zone B.

Usually, product mixtures d is decompressed to the pressure of 2-10 crust from the pressure of 20-60 crust.Any low-boiling compound such as ethane, ethene, methane, oxycarbide and the rare gas element that will be present among the product mixtures d are removed with propane and/or normal butane.Preferably make the air-flow e1 that comprises alkane (II) be recycled to the alkane dehydrogenation.

The air-flow e1 that comprises alkane (II) also can comprise low-boiling compound such as ethane, ethene, methane, oxycarbide and rare gas element and hydrogen.Usually, when not at step C) in it comprises the low-boiling compound that has or do not have hydrogen when carrying out the removing of above-mentioned (choosing wantonly) low-boiling compound and hydrogen (residual vaporous stream c3).Can from air-flow e1, remove son stream and from described method, discharge to prevent that secondary component from assembling.Can with should son stream burn or deliver in the processing step of alkane/alkene that recovery wherein exists.Recovery can be used as and absorbs or absorption, carries out as membrane sepn or rectifying.The hydrogen that is present in the materials flow can for example reclaim by transformation absorption.Alkane/the alkene that reclaims and the hydrogen of recovery all can be recycled to dehydrogenation.Also can from described method, discharge whole materials flow e1 or deliver to alkane/alkene that recovery wherein exists or the processing step of hydrogen in.

Under the situation of pure decompression, for realize on the one hand alkene/alkane and on the other hand the better separation between ester/acid mixture can distill in addition and/or rectifying.Need the reflux ratio of 0.2-1.5 and separating of common 10-20 theoretical tray for this reason.Here can use tray column, for example bubble-cap tray column and have the tower of random packing or have the tower of structured packing.

Also the pressure that product mixtures d clings to from 20-60 can be decompressed to common 2-45 crust, for example 10-40 crust, or the pressure that 25-32 clings in concrete variation scheme.Can two tower K1 of use as described below and K2 the materials flow e1 and the e2 aftertreatment that exist after will reducing pressure.

Can carry out each variation scheme of this aftertreatment.The remarkable part of variation scheme I is that " sharp " remove C ₃Component (propane and propylene), only very small amounts of propane and propylene are present in the bottom effluent (corresponding to materials flow e2) (for example about 100-1000 quality ppm).These advantages that change scheme are if having, only very small amount of C ₃Hydrocarbon enters step F subsequently) and G) in.When not removing C sharp ₃During component, corresponding to changing as described in the scheme II, this may necessarily require step F as hereinafter) and G) in higher levels of process complexity.

Change among the scheme Ia at one, the air-flow e1 that exists after the decompression is infeeded among the first tower K1.Pressure in this tower equals or only is lower than slightly the pressure of feed steam.Tower K1 is preferably the pure rectifying section of conventional tower, and promptly it does not have vaporizer, but has condenser, and preferred bottom feed at tower.The liquid stream e2 that exists after the decompression is infeeded the second tower K2.The pressure of tower K2 significantly is lower than the pressure of tower K1.Common pressure is that 30 crust (all pressure all are absolute) and K2 are 1.5 crust for for example K1.Usually the pressure among the K1 is the 10-40 crust, and preferred 25-32 crust is the 1-5 crust, preferred 1.3-2 crust in K2.Equally thing being extracted in the bottom of tower K1 infeeds among the tower K2.Materials flow is extracted corresponding to materials flow e1 in two tops of tower K1 and K2, and can further use as mentioned above or further aftertreatment.This moment, the top extraction thing of the second tower K2 preferably was directly recycled to dehydrogenation, the optional for this reason compressor that uses.

Change among scheme Ib at another, program is as described in changing under the scheme Ia, and difference is here the pressure of tower K2 higher (general value, K1=30 crust for example, K2=5 crust).Usually the pressure among the K1 is the 10-40 crust, and preferred 25-32 crust, the pressure among the K2 are the 2.5-7 crust, preferred 4-6 crust.This advantage that changes scheme is not need compressor.

Change among scheme Ic at another, program is as described in changing under the scheme Ia, and difference is the condenser temperature of tower K2 higher (for example about 40 ℃).Usually this temperature is 30-50 ℃, preferred 37-45 ℃.Therefore, the alkyl ester that materials flow still comprises vast scale is extracted at the top of tower K2, therefore not directly is recycled to dehydrogenation.Therefore this materials flow is compressed to the pressure of tower K1 and sends among the tower K1.In this variation scheme, only materials flow is extracted corresponding to materials flow e1 and can further use as mentioned above or further aftertreatment in the top of tower K1.Usually the pressure among the K1 is the 10-40 crust, and preferred 25-32 crust is the 1-5 crust, preferred 1.3-2 crust in K2.

Change in scheme II at another, program is as described in changing under the scheme Ib, and difference is to allow more substantial C in the bottom effluent of tower K2 ₃Component (propane and propylene) (for example about 1-2 quality %) makes bottom temp be limited to about 100-110 ℃, and does not produce the material requirements to the raising of the vaporizer of tower K2 and base section.Pressure among the tower K1 is generally the 10-40 crust, preferred 25-35 crust; Pressure among the tower K2 is generally the 2.5-7 crust, preferred 4-6 crust.

If it still comprises a large amount of relatively alkyl esters (V), then choose wantonly and also can handle recycle stream d2 in the same manner.Here also preferably distill the purification materials flow.This can be in independent tower, or alternatively in carrying out with the processing of materials flow d in the common tower.Can be meticulous purification after this by absorption, absorption, gas scrubbing or catalysis purification step.

Materials flow e2 can be introduced processing step F) in before will comprise alkyl ester (V) the further aftertreatment of product mixtures e2 of (form by alkyl ester (V) and paraffinic acid (IV) substantially, for example form) by isopropyl isovalerate and isovaleric acid.In distillation tower, can be with paraffinic acid (IV) as isovaleric acid from alkyl ester (V) as removing the isopropyl isovalerate.Paraffinic acid (IV) can be used as bottoms as isovaleric acid and obtains and be recycled to esterif iotacation step.Alkyl ester (V) can be used as isopropyl isovalerate that top product obtains and introduce processing step F in addition).Under the situation of separating isovaleric acid and isopropyl isovalerate, the example of the processing parameter that is fit to is for 1.5 clinging to the pressure of (all pressure all are absolute) and the reflux ratio of 0-3 at the most.Paraffinic acid (IV) remove positive influence processing step G) hydrolysis reactor in molecular balance.This makes higher hydrolysis conversion become possibility, and result in addition greatly reduces recycle stream (water=materials flow k1; Isopropyl isovalerate=materials flow h2).Because significantly littler recycle stream reduces for example fund and the energy requirement of the following stated equipment (1), (2), (3) and (4).Because at hydrolysing step F) before carry out removing of described paraffinic acid (IV), eliminated adding step D in addition) and hydrolysing step F) between influence each other.

At processing step F) in, make the product mixtures e2 that comprises alkyl ester (V) in the ester hydrolysis area, obtain comprising the product mixtures f of alkanol (I) (Virahol and/or 2-butanols) and paraffinic acid (IV) with the water reaction.At processing step G) in, alkanol (I) is taken out and reclaims paraffinic acid (IV) from product mixtures f.Paraffinic acid (IV) is recycled to esterif iotacation step D usually), or it is introduced absorption step to remove alkene and alkane from gas phase c3 as absorption agent.

In this step, product mixtures f can be divided into materials flow g1 that comprises paraffinic acid (IV) and alkyl ester (V) and water and the materials flow g2 that forms by alkanol (I) and water substantially.The mixture that materials flow g1 is divided into paraffinic acid (IV) and alkyl ester (V) and water by distillation.Paraffinic acid (IV) be recycled to esterif iotacation step D or to adsorption step from gas phase c3, to remove alkene and alkane, simultaneously, the mixture of alkyl ester (V) and water is recycled to ester hydrolysis area F.Depend on and balance each other, can be by simple distillation or by using entrainer (for example under the situation of Virahol, benzene, hexanaphthene or diisopropyl ether) azeotropic distillation, by using the extractive distillation of extraction agent (for example ionic liquid or acetate), and will from product mixtures f, take out by the g2 that alkanol (I)/water is formed by membrane method (pervaporation or vapor permeates).

Esterification can be carried out under homogeneous phase or heterogeneous catalysis.Be suitable on the esterolytic catalyzer principle for also being used for the above-mentioned catalyzer of esterification.Preferred heterogeneous catalyst is an ion exchange resin.Preferred homogeneous catalyst is sulfuric acid or heteropolyacid.

The ester hydrolysis area can be configured to reactor or reactive distillation column.The combination of reactor and reactive distillation column also is possible.

Ester hydrolysis and distillation can be carried out in the processing step that separates.In a variation scheme of the inventive method, make the Mischung 2 that comprises alkyl ester (V) in the ester hydrolysis reaction device, obtain comprising the product mixtures f of alkanol (I), paraffinic acid (IV), alkyl ester (V) and water with the water reaction, be connected in series then, if separate this mixture at least two distillation towers that suitable and next door tower link to each other.

Under the esterolytic situation of heterogeneous catalysis, the ester hydrolysis reaction device can be configured to fixed-bed reactor, trickle-bed reactor, fluidized-bed reactor or suspension reactor.Under the situation of fluidized-bed reactor, can operate catalyzer (so-called floating bed method) at point of fluidization by controllable manner.Under the esterolytic situation of homogeneous catalysis, reactor for example can be configured to stirred-tank reactor or tubular reactor.When ester hydrolysis homogeneous phase carries out, usually with catalyzer at processing step G) in usually extract materials flow and remove with paraffinic acid via the bottom of second distillation tower.At this moment, can be recycled to esterif iotacation step D at paraffinic acid) in before remove catalyzer, and can be with the catalyst recycle of removing to hydrolysis reactor.Can be in vaporizer or multistep distillation tower the heat extraction catalyzer, and in phase separator or by being separated and catalyzer is removed in the combination of thermal separation.When the homogeneous catalyst identical with esterification is used for the ester hydrolysis, can saves and remove catalyzer separately.For this process variant, heteropolyacid or sulfuric acid are particularly suitable.

For example, in first specific embodiments of the inventive method, used paraffinic acid (IV) is an isovaleric acid, and obtain containing the product mixtures e2 of isopropyl isovalerate, with in step F) in, make the product mixtures e2 that contains isopropyl isovalerate in the ester hydrolysis reaction device, obtain comprising Virahol with the water reaction, isovaleric acid, the product mixtures f of isopropyl isovalerate and water, with at step G) in, product mixtures f is divided into basically by isovaleric acid in first distillation tower (1), materials flow g1 that isopropyl isovalerate and water are formed and the materials flow g2 that forms by Virahol and water basically.Materials flow g1 is divided into materials flow h1 (it extracts materials flow as the bottom usually and obtains) that is made up of isovaleric acid basically and the materials flow h2 (it extracts materials flow as the top usually and obtains) that is made up of isopropyl isovalerate and water basically in second column (2).Materials flow h1 can be recycled to esterification zone or for removing any adsorption step that alkane/alkene mixture exists.Materials flow h2 is directly recycled in the hydrolysis reactor.This variation scheme is shown among Fig. 1.

For example, in second specific embodiments of the inventive method, used paraffinic acid (IV) is positive valeric acid, and obtain containing isopropyl isovalerate product mixtures e2 and

In step F) in, make contain isopropyl isovalerate product mixtures e2 in the ester hydrolysis reaction device with water reaction obtain comprising Virahol, valeric acid, isopropyl isovalerate and water product mixtures f and

At step G) in, product mixtures f is divided into basically materials flow g1 that is made up of valeric acid, isopropyl isovalerate and water and the materials flow g2 that is made up of Virahol and water basically in first distillation tower (1).Materials flow g1 is divided into materials flow h1 (it extracts materials flow as the bottom usually and obtains) that is made up of valeric acid basically and the materials flow h2 (it extracts materials flow as the top usually and obtains) that is made up of isopropyl isovalerate and water basically in second column (2).Materials flow h1 can be recycled to esterification zone or for removing any adsorption step that alkane/alkene mixture exists.Materials flow h2 is directly recycled in the hydrolysis reactor.

For example, in the 3rd specific embodiments of the inventive method, used paraffinic acid (IV) is a butyric acid, and obtains containing the product mixtures e2 of isopropyl butyrate, at this moment

In step F) in, make contain isopropyl butyrate product mixtures e2 in the ester hydrolysis reaction device with water reaction obtain comprising Virahol, butyric acid, isopropyl butyrate and water product mixtures f and

At step G) in, product mixtures f is divided into basically materials flow g1 that is made up of butyric acid, isopropyl butyrate and water and the materials flow g2 that is made up of Virahol and water basically in first distillation tower (1).Materials flow g1 is divided into materials flow h1 (it extracts materials flow as the bottom usually and obtains) that is made up of butyric acid basically and the materials flow h2 (it extracts materials flow as the top usually and obtains) that is made up of isopropyl butyrate and water basically in second column (2).Materials flow h1 can be recycled to esterification zone or for removing any adsorption step that alkane/alkene mixture exists.Materials flow h2 is directly recycled in the hydrolysis reactor.

Component distillation that can be by using entrainer such as benzene, hexanaphthene or diisopropyl ether is by azeotropic distillation column (3), phase separator (5) and remove the water that water tower (4) will be present among the materials flow g2 and remove and be recycled in the ester hydrolysis reaction device as materials flow k1.When obtaining diisopropyl ether as by product in the ester hydrolysis, used entrainer is preferably diisopropyl ether.Can extract materials flow i1 by the bottom that azeotropic distillation column (3) obtain is pure Virahol.

With at esterif iotacation step D) in use formic acid to compare as carboxylic acid with acetate, the present invention uses the higher alkane acid with 3 or more a plurality of carbon atoms as uses isovaleric acid that significant advantage is provided.For example, neither form alkyl ester/Virahol azeotrope, also do not form any alkyl ester/isopropanol azeotrope.Therefore, can from Virahol, remove alkyl ester in the mode of simple and " sharply " by distillation.In addition, can remove and be recycled to the ester hydrolysis area with alkyl ester by first and second distillation towers (1) and (2) with being present in from the most of water among the product mixtures f of ester hydrolysis area.This significantly reduces the water load of the component distillation of downstream separation alkanol/water mixture.

The ester hydrolysis is usually at 1-20 crust, and the pressure of preferred 2-5 crust and 50-150 ℃ usually carry out under preferred 80-120 ℃ the temperature.Preferably in the presence of acid ion exchangers, carry out as catalyzer.Water can stoichiometry not enough or excessive use; It is usually to use based on alkyl ester (V) stoichiometry is not enough.For example its consumption is a 0.5-0.9 moles/mole isopropyl isovalerate.Ester hydrolysis reaction can carry out with the floating bed pattern or in fixed-bed reactor in fluidized-bed reactor.

The product mixtures f that obtains in the ester hydrolysis reaction comprises for example 5-15 weight % Virahol, 10-40 weight % isovaleric acid (or valeric acid or butyric acid), 45-80 weight % isopropyl isovalerate (or isopropyl isovalerate or isopropyl butyrate) and 1-10 weight % water.Usually extract the materials flow g1 that materials flow obtains as the bottom of first tower (1) and comprise for example 32 weight % isovaleric acid (or valeric acid or butyric acid) and 64 weight % isopropyl isovalerates (or isopropyl isovalerate or isopropyl butyrate) and 4 weight % water.Usually extract the materials flow g2 that materials flow obtains as the top of first tower (1) and comprise for example 85 weight % Virahols and 15 weight % water.Usually extract the materials flow h1 that materials flow obtains as the bottom of second tower (2) and comprise 99 weight % isovaleric acid (or valeric acid or butyric acid) and 1 weight % isopropyl isovalerate (or isopropyl isovalerate or isopropyl butyrate), the materials flow h2 that obtains as the top extraction materials flow of second tower (2) comprises for example 93 weight % isopropyl isovalerates (or isopropyl isovalerate or isopropyl butyrate), 2 weight % isovaleric acid (or valeric acid or butyric acid) and 5 weight % water usually.

Usually extract the materials flow i1 that materials flow obtains as the bottom of the 3rd tower (3) and preferably comprise at least 98 weight % Virahols.Usually extract the materials flow i2 that materials flow obtains as the top of the 3rd tower (3) and comprise for example 25 weight % Virahols, 7 weight % water and 68 weight % entrainer such as hexanaphthenes.

In phase separator (5), the materials flow i2 that adds entrainer such as hexanaphthene is divided into water and organic phase.Water is introduced in the 4th tower (4) as refluxing and is preferably comprised at least 60 weight %, at the most 40 weight % Virahols and a small amount of entrainer.Organic phase as reflux to introduce the 3rd tower (3) and preferably comprise 20-50 weight % Virahol, less than 10 weight % water and 50-80 weight % entrainer.The bottom extraction materials flow k1 of the 4th tower (4) preferably comprises greater than 98 weight % water and is recycled to the ester hydrolysis area.

First tower (1) has 20-40 theoretical tray usually and moves under the pressure of 0.5-2 crust.Second tower (2) has 15-35 theoretical tray usually and moves under the pressure of 0.5-1.5 crust.The 3rd tower (3) has 10-30 theoretical tray usually and moves under the pressure of 0.5-4 crust.The 4th tower (4) has 1-15 theoretical tray usually and moves under the pressure of 0.5-2 crust.

Yet, also can be simultaneously in one and identical processing step, carry out to the hydrolysis of small part ester and distillation, at this moment, separate mixture by ester hydrolysis formation by being distilled to small part, paraffinic acid (IV) is if suitablely reclaim with homogeneous catalyst.The preparatory response device can be in the upstream of reactive distillation column.

This reaction distillation can carry out under homogeneous phase or heterogeneous catalysis.Reactive distillation column can contain conventional internals such as structured packing, random packing and column plate.Heterogeneous catalyst can the catalysis internals form, exist for example as regular catalyst filler or random catalyst filling, or with the form of catalyst suspension.

Describe the present invention in detail by following examples.

Embodiment

Embodiment 1

By commercial simulator program AspenPlus, for example calculate the complete a complete set of technology for preparing Virahol by propane.In this embodiment, described method comprises step (1)-(5) as mentioned above.These show with the materials flow of enclosing in Fig. 1.Used paraffinic acid is an isovaleric acid.The composition of each materials flow of calculating can be obtained by table 1.Analog calculation is based on the thermodynamical model on gas-liquid and liquid liquid equilibrium measuring result basis.

Embodiment 2

The method of simulation embodiment 1, difference are that used paraffinic acid (IV) is butyric acid but not isovaleric acid.The results are summarized in the table 2.

Claims (8)

1. one kind is selected from the method for the alkanol (I) of Virahol and 2-butanols by corresponding alkane (II) preparation that is selected from propane and normal butane, and described method comprises the steps:

A) provide the initial air-flow a that comprises alkane (II);

B) the initial air-flow a that will comprise alkane (II) infeeds dehydrogenation zone and alkane (II) is dehydrogenated to the product gas flow b of alkene (III) to obtain comprising alkene (III) and unconverted alkane (II), having or do not have higher-boiling compound, steam, hydrogen and low-boiling compound;

C) compressed product air-flow b at least optionally is divided into water c1 with product gas flow b, comprise alkene (III) with alkane (II), have or do not have the c2 mutually of higher-boiling compound and comprise hydrogen and the gas phase c3 of low-boiling compound;

D) make product gas flow b or comprise alkene (III) and the c2 mutually of alkane (II) in esterification zone with paraffinic acid (IV) reaction with 3 or more a plurality of carbon atoms to obtain comprising the corresponding alkyl ester (V) of paraffinic acid (IV) and the product mixtures d of unconverted alkane (II);

E) from product mixtures d, take out air-flow e1 and comprise the product mixtures e2 of alkyl ester (V), described air-flow e1 comprise alkane (II) and if the suitable dehydrogenation zone that is recycled to;

F) make the product mixtures e2 that comprises alkyl ester (V) in the ester hydrolysis area, obtain comprising the product mixtures f of alkanol (I) and paraffinic acid (IV) with the water reaction; With

G) alkanol (I) and paraffinic acid (IV) are recycled to esterification zone if taking-up is also suitable from product mixtures f with paraffinic acid (IV).

2. according to the process of claim 1 wherein step B) in dehydrogenation in the presence of oxygen, carry out.

3. according to the process of claim 1 wherein that dehydrogenation carries out in the presence of steam.

4. according to the process of claim 1 wherein step F) in reactive distillation column, carry out.

5. according to the process of claim 1 wherein step F) neutralize at least partially in carrying out in the reactive distillation column at least partially in ester hydrolysis pre-reactor.

6. according to the process of claim 1 wherein that used alkane (II) is a propane, at this moment, in step e) in obtain containing isopropyl esters reaction mixture e2 and

In step F) in, make the product mixtures e2 that contains isopropyl esters in the ester hydrolysis reaction device, obtain comprising Virahol with the water reaction, paraffinic acid (IV), the product mixtures f of isopropyl esters and water, with at step G) in, product mixtures f is divided in first distillation tower basically by paraffinic acid (IV), materials flow g1 that isopropyl esters and water are formed and the materials flow g2 that forms by Virahol and water basically, materials flow g1 is divided into basically materials flow h1 that is made up of paraffinic acid (IV) and the materials flow h2 that is made up of isopropyl esters and water basically in second column, component distillation by using entrainer is by azeotropic distillation column, phase separator and remove water tower and remove the water that is present among the materials flow g2, pure substantially Virahol extracts materials flow i1 as the bottom of azeotropic distillation column and obtains.

7. according to each method among the claim 1-6, wherein used paraffinic acid (IV) is butyric acid, valeric acid or isovaleric acid.

8. according to the method for claim 7, wherein used paraffinic acid (IV) is an isovaleric acid, obtains containing the product mixtures e2 of isopropyl isovalerate,

In step F) in, make the product mixtures e2 that contains isopropyl isovalerate in the ester hydrolysis reaction device, obtain comprising Virahol with the water reaction, isovaleric acid, the product mixtures f of isopropyl isovalerate and water, with at step G) in, product mixtures f is divided in first distillation tower basically by isovaleric acid, materials flow g1 that isopropyl isovalerate and water are formed and the materials flow g2 that forms by Virahol and water basically, materials flow g1 is divided into basically materials flow h1 that is made up of isovaleric acid and the materials flow h2 that is made up of isopropyl isovalerate and water basically in second column, component distillation by using entrainer is by azeotropic distillation column, phase separator and remove water tower and remove the water that is present among the materials flow g2, pure substantially Virahol extracts materials flow i1 as the bottom of azeotropic distillation column and obtains.

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