CN101774893A - Process for preparing m-cresol by nitrogen oxide gas - Google Patents
Process for preparing m-cresol by nitrogen oxide gas Download PDFInfo
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Abstract
The invention discloses a process for preparing m-cresol by a nitrogen oxide gas, which comprises the following steps: infusing the nitrogen oxide gas in m-toluidine sulfate for carrying out diazotization, hydrolyzing in the presence of an organic solvent and under an acidic condition, carrying out flash evaporation on the acid phase under the condition of negative pressure, returning the acid phase to a salifying step, dehydrogenating and rectifying the organic phase to obtain m-cresol products. The invention uses the nitrogen oxide gas as a diazotizing agent and inorganic salts do not exist in a waste acid so that the waste acid is possibly used industrially. The hydrolysis is carried out in the presence of the organic solvent, the m-toluidine generated by the hydrolysis is quickly dissolved in the organic phase, the side product tarry matters generated in the reaction is few, the yield of the m-toluidine is improved, the salt-free waste acid is subjected to the flash evaporation under the negative pressure at a certain temperature, organic matters are stripped while the reaction water is removed, sulfuric acid is used, the dosage of the sulfuric acid is reduced, the purity of the m-toluidine products prepared by the process of the invention is 99.7% and the yield is more than 90%.
Description
Technical field
The invention belongs to fine chemicals and make the field, be specifically related to a kind of technology of preparing m-cresol by nitrogen oxide gas.
Background technology
Cresols has 3 kinds of isomer, i.e. ortho-cresol, meta-cresol, p-cresol, and they all are important chemical material, meta-cresol chemistry 3-hydroxytoluene by name wherein, molecular formula C
7H
8O, be a kind of colourless to flaxen flammable liquid, the phenol smell is arranged, can be used for industries such as medicine, agricultural chemicals, dyestuff, spices, bucket resin, softening agent, cinefilm, oxidation inhibitor and reagent, be mainly used in synthetic meta-tolyl-N-methylcarbamate (MTMC), Tiguvon, antioxidant CA, industrial chemicals and products such as tribromocresol, 4-nitro m-cresol, 3-phenoxytoluene, a first phenyl ether, a methyldiphenyl aldehyde, cresol sulfonic acid calcium, DISPERSE YELLOW SE-5R, parachlorometacresol m-tolyl ester, 2-chloro-5-cresols, 4-chloro-3-cresols, m-hydroxybenzaldehyde.
Present meta-cresol preparation technology mainly contains:
(1) toluene sulfonation alkali fusion
100～110 ℃ of reactions down, be warming up to 150 ℃ by toluene and 98% sulfuric acid then, continue to add toluene, being warming up to 190 ℃ carries out isomerization, cuts out 201～208 ℃ close-cut fraction behind the alkali fusion with efficient distillation tower, between obtaining, the mixture of p-cresol; This material with after the benzene dilution, is added urea, at-10 ℃ of reaction 1h down, centrifugal suction filtration, benzene or toluene wash secondary with-10 ℃ obtain meta-cresol-urea white solid complex compound; In 15～80 ℃ with toluene hydrolysis complex compound, get liquid layer, after normal pressure steams toluene and water in rectifying tower, under vacuum tightness 0.1MPa, cut 91～104 ℃ fraction, obtain content and be the meta-cresol more than 95%.
(2) isopropyl toluene method
This method is to be raw material with toluene, in the presence of catalyzer, carries out alkylation reaction with propylene, gets through the oxidation acidolysis again.
Alkylation is to be catalyzer (consumption 1～2%) with the alchlor, 85～115 ℃ of temperature of reaction, propylene/toluene=0.4～0.6 (mol ratio).Can obtain the higher meta-isomer of yield with this understanding.
The used oxygenant of isopropyl toluene oxidation has air, pure oxygen or hydrogen peroxide.Generally both economical with atmospheric oxidation; oxidizing reaction is carried out in the presence of initiator (benzoyl peroxide or Diisopropyl azodicarboxylate); add-on is about 1% of an isopropyl toluene weight; 138～140 ℃ of temperature of reaction; reaction times 130～150min, air flow is excessive 5% by theoretical amount, and the reaction solution pH value is controlled at about 5; oxidation depth is controlled at 15%, and total with this understanding isopropyl toluene hydroperoxide are about 85～90%.
The isopropyl toluene hydrogen peroxide is decomposed into mixture cresol and acetone in the presence of sulfuric acid.In this method synthetic mixture cresol,, isomer proportion is roughly 6: 4.Mixture cresol in the presence of catalyzer, is carried out alkanisation with iso-butylene, obtain di-t-butyl meta-cresol and ditertbutylparacresol mixture.
Utilize the bigger characteristic of cresols tert-butylation product boiling-point difference, can be with its fractionation by distillation.Separate the back gained 4,6-tertiary butyl meta-cresol in the presence of catalyzer, through being heated to 202 ℃, can taking off hydrocarbon and be decomposed into meta-cresol and iso-butylene, products obtained therefrom meta-cresol content can reach more than 98%, the rate of recovery reaches about 95%.
(3) o xylene oxidation method
O-Xylol gets o-toluic acid by atmospheric oxidation under cobalt naphthenate catalysis, be catalyzer with cupric oxide and magnesium oxide again, o-toluic acid oxidative decarboxylation is transformed obtain meta-cresol.
These method gained crude phenols are refining through packing tower, and meta-cresol content can reach more than 95%, and refining yield can reach 92%.
(4) phynol method
Phynol method mainly is that employing phenol and methyl alcohol are the raw material production meta-cresol.
(5) tar slightly heats up in a steamer method
Mainly be with the by-product tar crude phenols in the coking repeatedly distill as raw material and purity lower (≤90%) meta-cresol product.
(6) chlorobenzene alkaline water solution
Hydrolysis process is for a first
It is important measuring high cresols production, and reaction is to carry out chlorination reaction by the toluene of 1mol and 1mol chlorine in the presence of iron trichloride and disulphur dichloride (sulfur oxychloride) (→ chlorinated hydrocarbon), obtains the mixture of 1: 1 ortho para toluene(mono)chloride.Use FeCl
3With other promotor, the ratio of neighbour/contraposition product all was possible from 3: 1 to 1: 2.Again at 360-390 ℃, and under 280-3300bar (28-330MPa) pressure, (2.5-33.5mol/mol) is hydrolyzed to mixture with excessive sodium hydroxide.Thermopositive reaction is to carry out continuously in the long pressure piping of hundreds of rice.Pipeline is a nickel system, can withstand the corrosion of reaction mixture.In the sodium cresylate solution that obtains, can discharge cresols by neutralization; Also can use the hydrochloric acid that in chlorination process, forms to be used for this step.By product sodium-chlor can be reused for chloric alkali electrolysis.With 1: 1 ortho para toluene(mono)chloride mixture, can obtain about 1: 2: 1 neighbour,, p-cresol.Also can pure ortho-chlorotolu'ene or parachlorotoluene come into operation.Hydrolysis is right-toluene(mono)chloride can obtain 1: 1 between/mixture of p-cresol, the hydrolysis ortho-chlorotolu'ene can obtain neighbour/meta-cresol mixture of 1: 1.Ortho-cresol by among the distillation latter just can obtain pure meta-cresol.
In the production method of above-mentioned several meta-cresols, toluene sulfonation alkali fusion operational path maturation, it is industrial method the earliest, but because this method consumes a large amount of soda acids, therefore quantity of three wastes is big, and equipment corrosion is serious, and also needs repeatedly to handle solid materials in the technological process, make and produce continuously relatively difficulty, and of poor quality.The advantage of isopropyl toluene method is a good quality of product, suitable for mass production, but disposable input is too big, and raw material can't solve.The meta-cresol purity that o-Xylol method and phynol method are produced is low, production cost height, and serious three wastes.Tar slightly heats up in a steamer the method raw material to be difficult to solve, and operational path is loaded down with trivial details, the cost height.Chlorobenzene alkaline hydrolysis law technology difficulty is big, and equipment corrosion is serious, and the product separation difficulty.
It is the new approaches of the synthetic meta-cresol of raw material with the meta-nitrotoluene that Hao Yanxia etc. (fiery explosive journal, 2002 the 1st phases) have proposed: at first by meta-nitrotoluene reduce meta-aminotoluene, then by meta-aminotoluene through diazotization, hydrolysis system meta-cresol.And mainly studied the synthesis technique for preparing meta-cresol by meta-aminotoluene, sulphuric acid soln concentration 30%, sodium nitrite solution feed rate are about 1mL/min when having drawn diazotization, the preferred process condition that sulphuric acid soln concentration is 50% during hydrolysis, the diazonium salt solution feed rate is about 12mL/min.
Be converted into the general at present production method of being interrupted that adopts of meta-cresol from meta-aminotoluene by diazotization, hydrolysis reaction.This method is with behind meta-aminotoluene and the sulfuric acid salify, splash into sodium nitrite solution at low temperatures, carry out diazotization and generate the meta-aminotoluene diazonium salt solution, again the meta-aminotoluene diazonium salt solution is joined the reaction that is hydrolyzed in the ebullient dilute sulphuric acid, adding benzene or toluene equal solvent extract in the time of hydrolytic process, redistillation removes and desolvates, and rectifying obtains meta-cresol.This method is owing to use sodium nitrite to do diazo reagent, and producing a large amount of about 25% saliferous dilute sulphuric acid can't handle.It is to adopt wet distillation in hydrolytic process that method is also arranged, the meta-cresol that reaction is generated steams with water vapour by distillation, obtain the meta-cresol aqueous solution, and then extract the meta-cresol of staying the meta-cresol in the reactor and steaming, steam solvent and obtain meta-cresol with benzene or toluene.But owing to will use a large amount of solvents, yield is lower, is generally about 70% in this processing method, simultaneously, because the viscous tar shape material that side reaction forms floats over the surface of reaction solution, has hindered meta-cresol and has taken reaction system out of with distillate, makes reaction time longer.
031282725 method that provides a kind of serialization to prepare meta-cresol of patent, be in the dilute sulphuric acid with the continuous adding 25～64% of meta-aminotoluene diazonium salt, adding speed, the speed that steams water and overflowing liquid by control meta-aminotoluene diazonium salt is from the take-off rate of overflow port, make that sulfuric acid concentration remains on 25～64% in the reactor, temperature of reaction remains on 106～150 ℃, the meta-cresol that reaction is generated steams with wet distillation continuously, contains a reaction of toluene by-product coke oily mater and sulfur waste acid and overflows from the overflow port of reactor continuously.Water that steams and meta-cresol mixture are isolated the meta-cresol crude product after layering, water discharges behind absorption with macroporous adsorbent resin, with the meta-cresol crude product in 2～10% aqueous sodium hydroxide solutions or steam or the methanol-eluted fractions recovery macroporous adsorbent resin.Acid separates after layering the reaction by-product coke oily mater that contains meta-cresol that overflows from the reactor overflow port with sulfur waste, sulfur waste acid recycles as the raw material of preparation meta-aminotoluene diazonium salt behind the absorption with macroporous adsorbent resin organic substance, and tarry matters discharges after the meta-cresol crude product is reclaimed in underpressure distillation.This method can continuously be produced meta-cresol, and production cost is lower, and the meta-cresol yield of content 99.5% has improved about 10% than discontinuous preparation method more than 84%.
200810235100 methods that provide a kind of direct hydrolysis to prepare meta-cresol of patent, be that meta-aminotoluene sulfuric acid (hydrochloric acid) salt is joined in the autoclave, control reaction temperature (200-280 ℃) and pressure, make it direct hydrolysis and generate meta-cresol and hydrogen sulfate amine, the sour water of generation discharges with in the alkali and back.This method can continuously be produced meta-cresol, and production cost is lower, and patent is introduced yield greater than 90%, but the severe lattice of reaction conditions, the high corrosion of High Temperature High Pressure, and " three wastes " amount is big.
In the aforesaid method, all will produce a large amount of saliferous spent acid, intractability is very big, but also type selecting, use, the maintenance of the equipment of giving bring difficulty.
Summary of the invention
The objective of the invention is: the technology that a kind of preparing m-cresol by nitrogen oxide gas is provided, the diazotization process that meta-aminotoluene is prepared meta-cresol improves, no inorganic salt generation in the spent acid after the diazotization reaction, spent acid through flash steam propose wherein water and organism after directly cover be used in industrial, reduce the vitriolic consumption, reduce the by-product coke oily mater, improve the yield of meta-cresol.
Technical solution of the present invention is: the preparation technology of this meta-cresol comprises the steps:
(1), salt-forming reaction: in becoming salt oven, add the sulphuric acid soln 598g～420g of mass concentration 15～40%, add meta-aminotoluene 60g under the room temperature while stirring, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to-3～5 ℃, slowly feed nitrogen oxide gas, the amount of controlled oxidation nitrogen is at 6300ml～7000ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln 190g-200g and the aromatic solvent 70g～100g that in hydrolytic reaction pot, add mass concentration 25～35%, be preheated to 70～105 ℃, drip above-mentioned meta-aminotoluene diazonium sulfate liquor below liquid level, flow velocity is 12～20mL/min, dropwise and under whipped state, keep 80 ℃～95 ℃ of temperature, constant temperature time 20min～25min, isolate sour phase, the organic phase crude product that contains meta-cresol removes under reduced pressure after washing and anhydrates and solvent, gets meta-cresol through rectifying again; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards.
Wherein, during salify, the vitriolic mass concentration is 15～40%, preferred 25～35%, preferred especially 30～35%.
Wherein, during salify, the mol ratio 1.5～4: 1, preferred 2～3: 1, preferred especially 2.5～2.8: 1 of sulfuric acid and meta-aminotoluene.
Wherein, diazo reagent is a nitrogen oxide gas, i.e. the equimolar mixture of nitrogen protoxide and nitrogen peroxide.
Wherein, described aromatic solvent is benzene, toluene, chlorobenzene or dimethylbenzene.
Wherein, hydrolysis temperature is 70～105 ℃, preferred 80～100 ℃, and preferred especially 85～95 ℃.
Wherein, the vacuum tightness of spent acid flash distillation is 0.085～0.095MPa, preferred 0.08～0.09MPa.
Wherein, the temperature when spent acid concentrates is 30～200 ℃, preferred 80～190 ℃.
Wherein, the sulfuric acid after concentrating is used for salify and diazotization operation, is preferably the salt operation.
Wherein, the organic phase crude product is washed to PH6, removes under reduced pressure and anhydrates and solvent, top temperature 105 ℃～115 ℃, 125 ℃～135 ℃ continuous rectifications of still temperature under the 45mmHg reduced pressure again.
Technology of the present invention compared with prior art has the following advantages:
1, carries out diazotization reaction with nitrogen oxide gas behind the employing meta-aminotoluene salify in the preparation process, eliminated the inorganic salt in the spent acid, reduced cost and difficulty that spent acid is handled.
2, the salt-free spent acid after the hydrolysis is gone back stripping and is gone out organic phase when reaction water is removed in vacuum flash, can directly be back into salt system.
3, useless vitriolic rationally utilizes, and has thoroughly solved the spent acid pollution difficult problem that the meta-aminotoluene method is produced meta-cresol, and the consumption of starting material vitriolic is descended greatly.
Embodiment
Followingly further specify technical solution of the present invention according to specific embodiment, and can not be interpreted as that these embodiment are the qualifications to technical solution, any change on the technology of the present invention solution basis still belongs to protection scope of the present invention.
Embodiment 1:
(1), salt-forming reaction: in reactor, add sulfuric acid 480 grams of mass concentration 40%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to 5 ℃, slowly feed the mixed gas of equimolar nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6300ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 190 gram mass concentration 25% and 70 gram benzene are added together be heated to 70 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 12mL/min, dropwise 80 ℃ of holding temperatures, under whipped state, be incubated 20min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 105 ℃ of top temperature, 125 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 53.1 more than 99.7% restrains yield 87.7%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.085MPa, the spent acid thickening temperature is 30 ℃.
Embodiment 2:
(1), salt-forming reaction: in reactor, add sulfuric acid 598 grams of mass concentration 37%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to 2 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6500ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 195 gram mass concentration 30% and 80 gram dimethylbenzene are added together be heated to 75 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 14mL/min, dropwise holding temperature at 85 ℃, under whipped state, be incubated 20min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 110 ℃ of top temperature, 130 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 54.3 more than 99.7% restrains yield 89.7%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.085MPa, the spent acid thickening temperature is 60 ℃.
Embodiment 3:
(1), salt-forming reaction: in reactor, add sulfuric acid 440 grams (the reuse acid of embodiment 1) of mass concentration 35%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to 2 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6500ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 200 gram mass concentration 30% and 85 gram toluene are added together be heated to 80 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 16mL/min, dropwise holding temperature at 85 ℃, under whipped state, be incubated 20min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 110 ℃ of top temperature, 130 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 56.2 more than 99.7% restrains yield 92.8%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.08MPa, the spent acid thickening temperature is 80 ℃.
Embodiment 4:
(1), salt-forming reaction: in reactor, add sulfuric acid 457 grams (the reuse acid of embodiment 2) of mass concentration 30%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to 0 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 7000ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 195 gram mass concentration 35% and 100 gram chlorobenzenes are added together be heated to 85 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 20mL/min, dropwise holding temperature at 90 ℃, under whipped state, be incubated 23min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 115 ℃ of top temperature, 135 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 56.6 more than 99.7% restrains yield 93.5%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.09MPa, the spent acid thickening temperature is 130 ℃.
Embodiment 5:
(1), salt-forming reaction: in reactor, add sulfuric acid 589 grams of mass concentration 28%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to-2 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6300ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 190 gram mass concentration 25% and 70 gram dimethylbenzene are added together be heated to 90 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 12mL/min, dropwise holding temperature at 95 ℃, under whipped state, be incubated 23min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 105 ℃ of top temperature, 125 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 55.9 more than 99.7% restrains yield 92.3%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.095MPa, the spent acid thickening temperature is 160 ℃.
Embodiment 6:
(1), salt-forming reaction: in reactor, add sulfuric acid 440 grams (the reuse acid of embodiment 5) of mass concentration 25%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to-3 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6500ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 195 gram mass concentration 30% and 85 gram toluene are added together be heated to 100 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 16mL/min, dropwise holding temperature at 90 ℃, under whipped state, be incubated 25min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 110 ℃ of top temperature, 130 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 55.2 more than 99.7% restrains yield 91.1%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.085MPa, the spent acid thickening temperature is 190 ℃.
Embodiment 7:
(1), salt-forming reaction: in reactor, add sulfuric acid 420 grams of mass concentration 20%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to-2 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6300ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 190 gram mass concentration 30% and 100 gram dimethylbenzene are added together be heated to 95 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 16mL/min, dropwise holding temperature at 90 ℃, under whipped state, be incubated 25min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 110 ℃ of top temperature, 130 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 54.6 more than 99.7% restrains yield 90.2%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.095MPa, the spent acid thickening temperature is 195 ℃.
Embodiment 8:
(1), salt-forming reaction: in reactor, add sulfuric acid 553 grams (the reuse acid of embodiment 7) of mass concentration 15%, in agitation condition downhill reaction still, add 60 gram meta-aminotoluenes, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to 2 ℃, slowly feed the mixed gas that waits mole nitrogen protoxide and nitrogen peroxide, the amount of nitrogen oxide is at 6500ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln of 200 gram mass concentration 35% and 100 gram chlorobenzenes are added together be heated to 105 ℃ in the reactor, drip above-mentioned diazonium salt below liquid level, flow velocity is 16mL/min, dropwise holding temperature at 95 ℃, under whipped state, be incubated 25min, isolate sour phase, the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, again under the 45mmHg reduced pressure 115 ℃ of top temperature, 135 ℃ of continuous rectifications of still temperature to get purity be that water white highly purified meta-cresol 53.4 more than 99.7% restrains yield 88.2%; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards, the vacuum tightness of spent acid flash distillation is 0.095MPa, the spent acid thickening temperature is 200 ℃.
Claims (10)
1. the technology of a preparing m-cresol by nitrogen oxide gas is characterized in that this technology may further comprise the steps:
(1), salt-forming reaction: in becoming salt oven, add the sulphuric acid soln 598g～420g of mass concentration 15～40%, add meta-aminotoluene 60g under the room temperature while stirring, obtain the meta-aminotoluene sulfate solution;
(2), diazotization reaction: above-mentioned meta-aminotoluene sulfate solution is added in the diazotization reaction still of band refrigerating unit, be cooled to-3～5 ℃, slowly feed nitrogen oxide gas, the amount of controlled oxidation nitrogen is at 6300ml～7000ml, make its reaction generate meta-aminotoluene diazonium vitriol, to making starch potassium iodide paper become blue, stopped reaction, and add urea and remove unnecessary nitrous acid;
(3), hydrolysis reaction: the sulphuric acid soln 190g-200g and the aromatic solvent 70g～100g that in hydrolytic reaction pot, add mass concentration 25～35%, be preheated to 70～105 ℃, drip above-mentioned meta-aminotoluene diazonium sulfate liquor below liquid level, flow velocity is 12～20mL/min, dropwise and under whipped state, keep 80 ℃～95 ℃ of temperature, constant temperature time 20min～25min, isolate sour phase, the organic phase crude product that contains meta-cresol removes under reduced pressure after washing and anhydrates and solvent, gets meta-cresol through rectifying again; Wherein solvent is applied mechanically; Wherein acid when reaction water is removed in flash distillation under condition of negative pressure stripping go out organism, the sulfuric acid reuse after concentrating, reaction water and organism are used for the washing procedure in road afterwards.
2. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: during salify, the vitriolic mass concentration is 15～40%, preferred 25～35%, preferred especially 30～35%.
3. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1 is characterized in that: during salify, and the mol ratio 1.5～4: 1, preferred 2～3: 1, preferred especially 2.5～2.8: 1 of sulfuric acid and meta-aminotoluene.
4. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: diazo reagent is a nitrogen oxide gas, i.e. the equimolar mixture of nitrogen protoxide and nitrogen peroxide.
5. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: described aromatic solvent is benzene, toluene, chlorobenzene or dimethylbenzene.
6. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: hydrolysis temperature is 70～105 ℃, preferred 80～100 ℃, preferred especially 85～95 ℃.
7. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: the vacuum tightness of spent acid flash distillation is 0.085～0.095MPa, preferred 0.08～0.09MPa.
8. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: the spent acid thickening temperature is 30～200 ℃, preferred 80～190 ℃.
9. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1 is characterized in that: the sulfuric acid after concentrating is used for salify and diazotization operation, is preferably the salt operation.
10. the technology of a kind of preparing m-cresol by nitrogen oxide gas according to claim 1, it is characterized in that: the organic phase crude product is washed to PH6, under reduced pressure, remove and anhydrate and solvent, top temperature 105 ℃～115 ℃, 125 ℃～135 ℃ continuous rectifications of still temperature under the 45mmHg reduced pressure again.
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| CN104140360A (en) * | 2014-07-10 | 2014-11-12 | 四川北方红光特种化工有限公司 | Method for preparing o-methylphenol |
| CN106916052A (en) * | 2017-04-20 | 2017-07-04 | 内蒙古佳瑞米精细化工有限公司 | A kind of preparation method of m-trifluoromethyl phenol |
| WO2023047194A1 (en) * | 2021-09-24 | 2023-03-30 | Deepak Nitrite Limited | SYSTEM AND PROCESS FOR CONTINUOUS PREPARATION OF meta-CRESOL BY NOx |
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| CN1202057C (en) * | 2003-07-03 | 2005-05-18 | 王林 | Continuous preparation of m-toluidine |
| CN101125800A (en) * | 2007-09-28 | 2008-02-20 | 中北大学 | Technique for preparing m-cresol |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104140360A (en) * | 2014-07-10 | 2014-11-12 | 四川北方红光特种化工有限公司 | Method for preparing o-methylphenol |
| CN104140360B (en) * | 2014-07-10 | 2015-12-02 | 四川北方红光特种化工有限公司 | Prepare the method for ortho-methyl phenol |
| CN106916052A (en) * | 2017-04-20 | 2017-07-04 | 内蒙古佳瑞米精细化工有限公司 | A kind of preparation method of m-trifluoromethyl phenol |
| WO2023047194A1 (en) * | 2021-09-24 | 2023-03-30 | Deepak Nitrite Limited | SYSTEM AND PROCESS FOR CONTINUOUS PREPARATION OF meta-CRESOL BY NOx |
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