CN103664717A - Preparation method of cheap and environmentally friendly D, L-2- hydroxyl-4-methylthio butyric acid - Google Patents
Preparation method of cheap and environmentally friendly D, L-2- hydroxyl-4-methylthio butyric acid Download PDFInfo
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Abstract
The invention belongs to the field of chemical engineering and relates to a preparation method of cheap and environmentally friendly D, L-2- hydroxyl-4-methylthio butyric acid. According to the method, the Andrussow method is adopted to prepare hydrocyanic acid gas mixture, and the hydrocyanic acid gas mixture and methylthio propionaldehyde react fully to obtain 2- hydroxyl-4-methylthio butyronitrile system under the catalytic action of alkali; the 2- hydroxyl-4-methylthio butyronitrile system reacts with mineral acid, and is hydrolyzed to obtain a 2- hydroxyl-4-methylthio butyric acid reaction solution, the reaction solution is neutralized via alkali, methyl tertiary butyl ether is added to remove water via distillation, solid-liquid separation is performed on the residuum, the filtrate is steamed to obtain methyl tertiary butyl ether, and the residuum is high-purity 2- hydroxyl-4-methylthio butyric acid. The D, L-2- hydroxyl-4-methylthio butyric acid prepared through the method disclosed by the invention is high in purity and monomer content, the production and operation are simple, the equipment requirement is low, the production cost is low, the environmental protection is realized, and the excellent industrialized production value is achieved.
Description
Technical field
The present invention is directed to chemical field, relate to a kind of eco-friendly D of cheapness, the preparation method of L-2-hydroxy-4-methylthiobutyric acid.
Background technology
Methionine hydroxy analog (MHA) claim again D, and L-2-hydroxy-4-methylthiobutyric acid is a kind of methionine additive.MHA and salt thereof have replaced methionine(Met) for a long time, are widely used in animal-feed, are mainly used in ruminating animal, for broiler chicken and aquatic animal, have also obtained good effect.Compare with methionine(Met), MHA is in a liquid state, and is convenient to feed-grain maker's use.
D, when L-2-hydroxy-4-methylthiobutyric acid is mainly used with water-based concentrated solution, except containing monomer whose, also has a certain amount of oligomer, is mainly dimer and tripolymer.In commercially available formulation, D, L-2-hydroxy-4-methylthiobutyric acid total content is 88%～90%(weight) product in, oligomer total amount only can be controlled at 20%(weight) in.These oligomers exist mainly with the form of ester or acid anhydrides, and weak effect when further other products are prepared in processing, affects end product quality.As while preparing HMBC, oligomer is difficult to and calcium oxide or calcium hydroxide reaction, is finally adsorbed on product surface, the dry difficulty of product, and then affect product quality.
In most of patents and bibliographical information, D, the raw material of L-2-hydroxy-4-methylthiobutyric acid is all to adopt through refining methylthiopropionaldehyde to react with High Purity Hydrogen cyanic acid, preparation 2-2-hydroxy-4-methylthio butyronitrile, 2-2-hydroxy-4-methylthio butyronitrile is hydrolyzed preparation D, L-2-hydroxy-4-methylthiobutyric acid again.Mainly contain following three processes:
(1) refining 3-methylthiopropionaldehyde (more than 99%) reacts with High Purity Hydrogen cyanic acid (more than 99%) and generates 2-2-hydroxy-4-methylthio butyronitrile, claims again MMP-cyanalcohol or MMP-CN, and reaction formula is as follows:
(2) the 2-2-hydroxy-4-methylthio butyronitrile obtaining and excessive mineral acid generation hydration reaction, generate intermediate 2-2-hydroxy-4-methylthio butyramide, claims again MHA-acid amides, and reaction formula is as follows:
(3) 2-2-hydroxy-4-methylthio butyramide is added to a certain amount of water and be hydrolyzed again generation D, L-2-hydroxy-4-methylthiobutyric acid, reaction formula is as follows:
From above-mentioned reaction, 2-2-hydroxy-4-methylthio butyronitrile is to produce D, the important intermediate of L-2-hydroxy-4-methylthiobutyric acid, and its yield size and cost drop into, the D to final production, quality and the cost of L-2-hydroxy-4-methylthiobutyric acid have material impact.
In theory, the preparation of 2-2-hydroxy-4-methylthio butyronitrile is known, mainly comprises following two kinds of modes:
(1) methylthiopropionaldehyde reacts and makes with prussic acid under the catalysis of alkali;
(2) methylthiopropionaldehyde reacts and makes with alkali metal cyanide under sodium bisulfite effect.
The disclosed method of US5756803 is a kind of concrete grammar that mode (1) is prepared 2-2-hydroxy-4-methylthio butyronitrile.The method is used the damping fluid of citric acid and sodium hydroxide formation as catalyzer, and the pH of solution is controlled at 4 left and right, and catalysis methylthiopropionaldehyde reacts with prussic acid, obtains 2-2-hydroxy-4-methylthio butyronitrile.Wherein, prussic acid excessive 2%～5%.The use of buffered soln and excessive prussic acid are conducive to the long-term preservation of product 2-2-hydroxy-4-methylthio butyronitrile.The 2-2-hydroxy-4-methylthio butyronitrile obtaining obtains MHA by mineral acid hydrolysis, or reacts with bicarbonate of ammonia, generates 5-(2-methylmercaptoethyl)-glycolylurea, salt of wormwood hydrolysis, carbonic acid gas neutralization obtains D, L-Methionine.
The disclosed method of US2745745 is a kind of concrete grammar that mode (2) is prepared 2-2-hydroxy-4-methylthio butyronitrile.The 2-2-hydroxy-4-methylthio butyronitrile obtaining, needs after reaction finishes with organic solvent-benzene extraction, obtains containing 2-2-hydroxy-4-methylthio butyronitrile benzole soln, dry, steaming removes organic solvent-benzene, obtain 2-2-hydroxy-4-methylthio butyronitrile, then with inorganic acid reaction, obtain MHA.
Obviously, in these bibliographical informations, no matter take which kind of mode to synthesize 2-2-hydroxy-4-methylthio butyronitrile, in order to obtain high yield, all need purer prussic acid, and prussic acid is excessive often, the rectifying purifying that prussic acid is extra and excessive use all can cause the increase of cost, the increase of this cost, particularly in technical scale, will cause huge financial loss.Moreover method as disclosed in US2745745, under unsuitable catalyzer is used, may cause the formation of cyaniding byproduct in process thing, and then be that subsequent purification and downstream production make troubles.
On the other hand, how to the D preparing, L-2-hydroxy-4-methylthiobutyric acid carries out separation and purification, to reduce energy consumption, to simplify the operation, is also to reduce D, the major way of L-2-hydroxy-4-methylthiobutyric acid production cost.
Patent CN1069311C discloses a kind of preparation method of MHA, and it is by the method for solid/liquid separation, and liquid methionine expends greatly, the reluctant shortcoming of waste material to have overcome that liquid-liquid extraction, solid-liquid were separated in the past.The technical scheme that the method adopts is: after the hydrolysis of 2-2-hydroxy-4-methylthio butyronitrile, add ammonia or ammonia neutralization, mixture is through evaporation, until seldom moisture or anhydrous existence, then by acetone treatment the residuum containing MHA and ammonium sulfate, obtain suspension, in suspension, isolate solids component thus, obtain the acetone soln that contains MHA, then, by removing in the solution of the self-contained liquid methionine of acetone, obtain liquid methionine.There is following shortcoming in this technical scheme: steams the power consumption of water process greatly; After water steams and removes, MHA and ammonium sulfate are very sticky, can be bonded on the wall of reactor, cause the heat transfer of system and mass transfer inhomogeneous; Because acetone and water dissolve each other, more difficult with the acetone purification ratio of water, recover acetone utilization needs rectifying, increases the input of equipment.
For these reasons and prior art, still need further D, the preparation method of L-2-hydroxy-4-methylthiobutyric acid improves, to reduce production costs, to simplify the operation.
Summary of the invention
In view of this, the invention provides a kind of D, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, the method is simple to operate, production cost is low, the D making, L-2-hydroxy-4-methylthiobutyric acid purity is high, monomer content is high.
For achieving the above object, technical scheme of the present invention is:
D, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, comprises the following steps:
A, take methane, ammonia and oxygen as raw material, adopt iS-One method composition principle, be prepared into prussic acid gas mixture I; Described prussic acid gas mixture I is processed to obtain prussic acid gas mixture II through deamination;
B, described prussic acid gas mixture II and methylthiopropionaldehyde, under the katalysis of alkali, fully react to obtain 2-2-hydroxy-4-methylthio butyronitrile system;
The reaction that is hydrolyzed under the existence of mineral acid of C, described 2-2-hydroxy-4-methylthio butyronitrile system, the reaction solution obtaining neutralizes through alkali, obtains D, the mixed system of L-2-hydroxy-4-methylthiobutyric acid and inorganic acid salt;
D, in described mixed system, add methyl tertiary butyl ether, redistillation dewaters, and obtains the methyl tertbutyl ethereal solution of inorganic acid salt and MHA, and inorganic acid salt is removed in separation, obtains filtrate; Described filtrate steams methyl tertiary butyl ether, obtains residue and is highly purified MHA.
Described iS-One method (Andrussow method) is the industrial process completing the 1950's, is the main method of producing prussic acid.The main raw material that it adopts has methane, ammonia and oxygen, therefore be again methane oxidation proceses of ammonia.This method is under condition more than normal pressure, l000 ℃, the silk screen that the logical people of material mixed gas is made by platinum, rhodium alloy catalyst platinum and rhodium, or the wire-mesh catalyst bed of being made by platinum iridium alloy, and the oxidative ammonolysis carrying out, its reaction formula is 2CH
4+ 2NH
3+ 30
2→ 2HCN+6H
20.At present, this technology is very ripe, has special prussic acid synthetic tower for the preparation of hydrocyanic acid gas.
Described deamination processing refers to the standby prussic acid gas mixture I of iS-One legal system is passed in acid, sloughs the operation of ammonia.The Main Function that described acid rises is absorbing ammonia G&W steam, so preferably sulfuric acid, the sulfuric acid that further preferred mass mark is 75%～90%.The prussic acid gas mixture of the present invention before and after deamination is processed all can be used for the preparation of 2-2-hydroxy-4-methylthio butyronitrile, and just the prussic acid gas mixture II character after deamination is processed is more excellent.Industrial, special acid tower can be set and for deamination, process.
Further, described prussic acid gas mixture I is preferably comprised of the component of following mass percent: hydrocyanic acid gas 8.8% ± 2%, water vapour 3.9% ± 2%, ammonia 1.6% ± 2%, hydrogen 1.1% ± 2%, nitrogen 76.0% ± 2%, oxygen 1.5% ± 2%, carbon monoxide 5.6% ± 2%, carbonic acid gas 1.1% ± 2%, methane 0.4% ± 2%.Described prussic acid gas mixture II is preferably comprised of the component of following mass percent: hydrocyanic acid gas 9.4% ± 2%, hydrogen 1.6% ± 2%, nitrogen 79.4% ± 2%, oxygen 1.7% ± 2%, carbon monoxide 5.8% ± 2%, carbonic acid gas 1.5% ± 2%, methane 0.6% ± 2%.
Described prussic acid gas mixture II is particularly suitable as the raw material of preparation 2-2-hydroxy-4-methylthio butyronitrile.Its reaction is except making 2-2-hydroxy-4-methylthio butyronitrile, in reaction solution, also contain remaining massfraction and be 0.05%～0.5% prussic acid and 2%～5% water, just because of the existence of residual hydrogen cyanic acid and water, this system (being that 2-2-hydroxy-4-methylthio butyronitrile is together with reaction solution) can long-term storage and is not decomposed.The reaction system of 2-2-hydroxy-4-methylthio butyronitrile also can be further adjusted to pH with acid 2～4 to be deposited, like this, even if still keep at normal temperatures longer stability.The acid of described adjusting pH can be sulfuric acid, phosphoric acid etc., massfraction preferably 85%.2-2-hydroxy-4-methylthio butyronitrile system, without carrying out any separation and purification, can be directly used in the production of MHA.
Further, described methylthiopropionaldehyde is not purified methylthiopropionaldehyde, wherein contains the heavy constituent of the methylthiopropionaldehyde of massfraction 94.5%～96%, the light constituent of massfraction 3.5%～5.3% and massfraction 0.2%～0.5%; Described light constituent is thiomethyl alcohol, methyl alcohol, propenal and water; Described restructuring is divided into dipolymer and the trimer of methylthiopropionaldehyde.
Step B is the nucleophilic addition under base catalysis.The alkali of described katalysis is organic bases and/or mineral alkali; The consumption of the alkali of described katalysis is that the pH that maintains reaction system is 4.0～6.5, and preferably pH is 5.0～5.5.The preferred low-molecular-weight amine compound of described organic bases, the further preferred aminated compounds of 3～20 carbon atoms, this compounds can, with methylthiopropionaldehyde arbitrarily than mixing, be conducive to fast reaction speed.The aminated compounds of described 3～20 carbon atoms comprises triethylamine, tri-isopropanolamine, DMA, imidazoles, picoline, pyridine etc., use wherein one or more can, particularly preferably triethylamine and/or pyridine.Described mineral alkali is one or more in metal hydroxides, metal cyanides, metal carbonate and alkali metal bicarbonate salt, or is ammonia.Described metallic hydrogen oxidation compound, as sodium hydroxide or potassium hydroxide; Metal cyanides, as sodium cyanide or potassium cyanide; Metal carbonate, as sodium carbonate or salt of wormwood; Alkali metal bicarbonate salt, as sodium bicarbonate or saleratus.Independent a kind of mineral alkali or mixed base can.
Further, in the alkali of described katalysis, also add acid, form mixture or the damping fluid of bronsted lowry acids and bases bronsted lowry; Described acid comprises mineral acid and organic acid.Adding or the formation of damping fluid of acid, can make reaction system maintain within the scope of more stable pH value.Described organic acid is a kind of in acetic acid, formic acid, citric acid, Phenylsulfonic acid, trifluoromethanesulfonic acid etc.; Described mineral acid is sulfuric acid or phosphoric acid.The damping fluid that forms is as Trisodium Citrate-sodium hydrate buffer solution, sodium succinate-sodium hydrate buffer solution, acetic acid-sodium hydrate buffer solution etc., optimization citric acid-sodium hydrate buffer solution.
In described step B, the mol ratio of prussic acid and methylthiopropionaldehyde is 1:1.0～1.05; Reaction pressure is 0.09～0.5MPa, and in negative pressure, the environment to malleation can react, for considering of equipment requirements and reaction efficiency, and preferably 0.1～0.3MPa, more preferably 0.1～0.15MPa; Temperature of reaction is 30～80 ℃, preferably 35～60 ℃, and more preferably 40～45 ℃.
In step C, described mineral acid comprises sulfuric acid, concentrated hydrochloric acid, phosphoric acid etc., preferably sulfuric acid.Described alkali is one or more in alkalimetal oxide, oxyhydroxide, alkali metal carbon oxide compound, liquefied ammonia or ammoniacal liquor.Described oxyhydroxide is as sodium hydroxide, potassium hydroxide etc.; Alkali metal carbon oxide compound is as sodium carbonate, salt of wormwood, sodium bicarbonate, saleratus etc.The present invention is for the consideration of subsequent purification, and preferred weakly alkaline ammoniacal liquor, liquefied ammonia or ammonia, neutralize and can additionally not introduce other salts simultaneously.In and time alkali consumption depend on mineral acid, as while being sulfuric acid and ammoniacal liquor, the consumption of ammoniacal liquor is as the criterion for ammonium sulfate for sulfuric acid or monoammonium sulfate are neutralized completely.Neutral temperature is 40～70 ℃, preferably 50～60 ℃.
Further, when mineral acid is sulfuric acid, the mol ratio of 2-2-hydroxy-4-methylthio butyronitrile and sulfuric acid is 1:0.5～1, and preferred molar ratio is 1:0.7～1; Described 2-2-hydroxy-4-methylthio butyronitrile successively obtains MHA through hydration reaction and hydrolysis reaction.During described hydration reaction, the massfraction of sulfuric acid is 50%～80%, and preferred mass mark is 65%～75%; Temperature is controlled at 40～70 ℃, and preferably temperature is 50～65 ℃.During described hydrolysis reaction, thin up sulfuric acid to the massfraction of sulfuric acid is 40%～50%, is preferably diluted to 45%～50%; Temperature is controlled at 90～130 ℃, preferably 100～110 ℃.During hydrolysis reaction, the concentration dilution of sulfuric acid, to the required concentration of hydrolysis reaction, is preferably in 30 minutes and temperature is risen to the required temperature of hydrolysis reaction, can effectively avoid the generation of intermediate by-products.Described dilute sulphuric acid water used is fresh water for the first time, the water of condensation distilling in rear available step D.Raw material and the product changing conditions of the method monitoring reactions such as available HPLC are stopped reaction until react completely.In above-mentioned sulfuric acid concentration and temperature condition, the hydration reaction time is 0.5～2h, and the preferred reaction time is 1～2h; Hydrolysis time is 2～4h, preferably 2.5～3h.
In described step D, the methyl tertiary butyl ether adding and D, the mixed system of L-2-hydroxy-4-methylthiobutyric acid and inorganic acid salt forms lower boiling water liquid azeotropic system, only needing lesser temps to distill dewaters, reduce energy consumption and shorten and steam the water time, and methyl tertiary butyl ether plays D, the effect of the extraction of L-2-hydroxy-4-methylthiobutyric acid and inorganic acid salt crystallization body.In addition, the existence of methyl tertiary butyl ether in evaporation system, can weaken the viscosity of feed liquid, reduces D, and L-2-hydroxy-4-methylthiobutyric acid and inorganic acid salt adhering on reactor wall, the system that prevents is conducted heat and mass transfer inhomogeneous; Methyl tertiary butyl ether and water do not dissolve each other, and the methyl tertiary butyl ether that steaming water steams is simultaneously without process rectifying, and static water phase separated can be returned to system, recycle.Further, the temperature that described distillation dewaters is controlled at 55～75 ℃, preferably 60～70 ℃.The add-on of methyl tertiary butyl ether is at least can completely take the water in evaporation system to be limited out of.Lower boiling distillation water rem oval is high, energy consumption is low, can also effectively reduce the generation of side reaction.
After step D has operated, the residue D of acquisition, L-2-hydroxy-4-methylthiobutyric acid, through content analysis, benefit is diluted with water to commercial grade content and can sells.Separated by product ammonium sulfate obtains white, highly purified ammonium sulfate through drying, can be for agricultural.
Another object of the present invention is to provide a kind of D of utilization, L-2-hydroxy-4-methylthiobutyric acid production equipment is prepared D, the method of L-2-hydroxy-4-methylthiobutyric acid, the method is simple to operate, equipment is simple, production cost is low, without waste water and dregs, discharge, the D making, L-2-hydroxy-4-methylthiobutyric acid purity is high, monomer content is high, and cheapness and environmental friendliness have good suitability for industrialized production and be worth.
For achieving the above object, technical scheme of the present invention is:
Utilize D, L-2-hydroxy-4-methylthiobutyric acid production equipment is prepared D, the method of L-2-hydroxy-4-methylthiobutyric acid, described production equipment comprises prussic acid synthetic tower, acid tower, reactor and tripping device, in described acid tower, fill massfraction and be 75%～90% sulfuric acid, described reactor is provided with pressure and temperature regulates supplementary unit, and the air outlet of prussic acid synthetic tower is communicated with the inlet mouth of acid tower by pipeline, and the air outlet of acid tower is communicated with reactor by being provided with the pipeline of throttling valve;
A, take methane, ammonia and oxygen as raw material, adopt iS-One method composition principle, by prussic acid synthetic tower, prepare prussic acid gas mixture I; Described prussic acid gas mixture I passes into acid tower and sloughs ammonia and water vapour, obtains prussic acid gas mixture II;
B, described prussic acid gas mixture II, under throttle valve control, pass in the methylthiopropionaldehyde in reactor with the speed of 250～350L/min, under the katalysis of alkali, fully react to obtain 2-2-hydroxy-4-methylthio butyronitrile system;
Under C, vigorous stirring, in reactor, add sulfuric acid to mix with 2-2-hydroxy-4-methylthio butyronitrile system, successively process hydration reaction and hydrolysis reaction obtain the reaction solution of MHA; During described hydration reaction, the massfraction of sulfuric acid is 50%～80%, and temperature is controlled at 40～70 ℃; During described hydrolysis reaction, thin up sulfuric acid is 40%～50% to the massfraction of sulfuric acid, and temperature is controlled at 90～130 ℃; The reaction solution that obtains MHA neutralizes through alkali, obtains D, the mixed system of L-2-hydroxy-4-methylthiobutyric acid and vitriol;
D, in described mixed system, add methyl tertiary butyl ether, redistillation dewaters, and obtains the methyl tertbutyl ethereal solution of vitriol and MHA, through tripping device separation, removes vitriol, obtains filtrate; Described filtrate is returned to reactor, steams methyl tertiary butyl ether, obtains residue and is highly purified MHA; The dilution to next step C sulfuric acid capable of circulation of the described water distilling out; The production to next step D capable of circulation of the described methyl tertiary butyl ether steaming.
Further, described reactor is also with water trap.In removal process, the methyl tertiary butyl ether steaming reaches oily water separation by water trap, and organic phase methyl tertiary butyl ether is got back to and steamed in water system, and isolated water cycle is applied mechanically to sulfuric acid and diluted.
In described step C, when sulfuric acid mixes with 2-2-hydroxy-4-methylthio butyronitrile system, the sequencing adding does not affect the carrying out of reaction, but for sulfuric acid, dilutes the consideration of heat release, for preventing bumping, preferably in sulfuric acid, drips 2-2-hydroxy-4-methylthio butyronitrile.
Described tripping device can be whizzer, suction filter, gets rid of worry machine etc.Wherein, that described reactor possesses is synthetic, the function of hydrolysis, neutralization, crystallization and distillation, corresponding utility appliance such as cooling, heating, supercharging that are equipped with also, but reactor used in the present invention is not limited to this, the equipment such as hydrolytic reaction pot, still kettle that also can arrange separately are in addition to complete corresponding function.The reaction conditions of optimizing in the first inventive method, the also method of applicable this part band production equipment.
Useful technique effect of the present invention is:
(1) adopt standby prussic acid gas mixture and the not purified methylthiopropionaldehyde of iS-One legal system, raw material, without rectifying purifying, is saved the production time, has improved production efficiency, has also reduced production cost; The 2-2-hydroxy-4-methylthio butyronitrile system preparing, stable in properties, can long-term storage, is more conducive to the production of follow-up MHA.
(2) the 2-2-hydroxy-4-methylthio butyronitrile system obtaining just can be directly used in the preparation of MHA without separation and purification, and the D obtaining, L-2-hydroxy-4-methylthiobutyric acid purity is high, monomer content is high, the equipment that relates to is simple, energy consumption is low, controllability is strong, cheapness and environmental friendliness, have good suitability for industrialized production and be worth.
(3) in separation and purification process, add organic solvent methyl tertiary butyl ether to form lower boiling water liquid azeotropic system, not only improved steaming water speed, and reduced energy consumption; In steaming the process of water, adopt water trap equipment, not only separated water outlet, and the methyl tertiary butyl ether that steams condensation can automated cycle to steaming in water system, reduced the usage quantity of organic solvent, and methyl tertiary butyl ether can recycled, without rectifying purifying.
(4) the water of condensation dilution of applying mechanically to sulfuric acid capable of circulation of reclaiming in whole production technique; The purity of by product vitriol is high, can be used for agricultural.
To sum up, the methylthiopropionaldehyde that utilization of the present invention is not purified and prussic acid gas mixture replace the methylthio group of process rectifying for propionic aldehyde and High Purity Hydrogen cyanic acid liquid, not only obtain D, the quality of L-2-hydroxy-4-methylthiobutyric acid and the D that uses the methylthiopropionaldehyde that obtains through rectifying and High Purity Hydrogen cyanic acid liquid reactions to obtain, the quality of L-2-hydroxy-4-methylthiobutyric acid is suitable, and there is the features such as production operation is simple, equipment requirements is low, production cost is low, environmental friendliness, there is good suitability for industrialized production and be worth.
Accompanying drawing explanation
Fig. 1 is D, the production equipment structural representation of L-2-hydroxy-4-methylthiobutyric acid.
Embodiment
Hereinafter with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.The experimental technique of unreceipted actual conditions in preferred embodiment, carries out according to normal condition.
Embodiment 1
To detecting from prussic acid synthetic tower prussic acid gas mixture I out, the consisting of of prussic acid gas mixture I: hydrocyanic acid gas 8.87%, water vapour 3.88%, ammonia 1.64%, hydrogen 1.13%, nitrogen 76.01%, oxygen 1.48%, carbon monoxide 5.67%, carbonic acid gas 1.13%, methane 0.39%.
Prussic acid gas mixture I after 75% sulfuric acid tower absorbs the ammonia and water vapour thereof in gas mixture, the consisting of of the prussic acid gas mixture II obtaining: hydrocyanic acid gas 9.35%, hydrogen 1.57%, nitrogen 79.44%, oxygen 1.71%, carbon monoxide 5.79%, carbonic acid gas 1.50%, methane 0.64%.
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 223.3g massfraction, contains 3.3g pyridine in methylthiopropionaldehyde.Under normal pressure, react, controlling temperature of reaction is 45 ℃, and draft speed is 300L/min, and tail gas absorbs with sodium hydroxide, with the residual volume of HPLC monitoring methylthiopropionaldehyde.When methylthiopropionaldehyde residual volume is less than 0.2%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 270.64g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 98%, prussic acid remnants 0.5%.The 2-2-hydroxy-4-methylthio butyronitrile obtaining is divided into two parts together with reaction solution (being 2-2-hydroxy-4-methylthio butyronitrile system).Portion wherein adds 8.5g water, under 3 ℃ of conditions, preserves 120 days, has no decomposition; Another part adds 8.5g water wherein, then with 85% sulfuric acid acidation to pH be 3, under 20 ℃ of conditions, preserve 120 days, 2-2-hydroxy-4-methylthio butyronitrile rate of decomposition is 0.1%.
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 223.3g massfraction, contains the water of 2.2g pyridine and 10g in methylthiopropionaldehyde.Under 0.15MPa, controlling temperature of reaction is 42 ℃, and draft speed is 280L/min, and tail gas absorbs with sodium hydroxide, with the residual volume of HPLC monitoring methylthiopropionaldehyde.When methylthiopropionaldehyde residual volume is less than 0.5%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 279.54g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 98%, prussic acid remnants 0.07%.
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 247.2g massfraction, contains the water of 2.2g pyridine and 15g in methylthiopropionaldehyde.Under 0.5MPa, controlling temperature of reaction is 45 ℃, and draft speed is 280L/min, and tail gas absorbs with sodium hydroxide, with the residual volume of HPLC monitoring methylthiopropionaldehyde.When methylthiopropionaldehyde residual volume is less than 0.2%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 294.54g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 98%, prussic acid remnants 0.07%.
Embodiment 5
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 227.3g massfraction, contains the water of 3.3g pyridine and 4g in methylthiopropionaldehyde.Under 0.09MPa, controlling temperature of reaction is 80 ℃, and draft speed is 350L/min, and tail gas carries out burning disposal, and incineration temperature is higher than 1000 ℃.With the residual volume of HPLC monitoring methylthiopropionaldehyde, when methylthiopropionaldehyde residual volume is less than 0.2%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 277.4g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 97%, prussic acid remnants 0.06%, moisture content 2%.
Embodiment 6
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 237.3g massfraction, contains 8.5g water in methylthiopropionaldehyde, in mixed system, adds a certain amount of catalyzer carbonic acid sodium, and the pH that keeps system in passing into prussic acid gas mixture process is 5.5.Under 0.5MPa, controlling temperature of reaction is 30 ℃, and draft speed is 350L/min, and tail gas carries out burning disposal, and incineration temperature is higher than 1000 ℃.With the residual volume of HPLC monitoring methylthiopropionaldehyde, when methylthiopropionaldehyde residual volume is less than 0.2%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 287.4g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 96%, prussic acid remnants 0.06%, moisture content 3%.
Embodiment 7
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 233.3g massfraction, contains 8.5g water in methylthiopropionaldehyde, in mixed system, adds a certain amount of catalyst of triethylamine, and the pH that keeps system in passing into prussic acid gas mixture process is 5.5.Under normal pressure, react, controlling temperature of reaction is 40 ℃, and draft speed is 350L/min, and tail gas carries out burning disposal, and incineration temperature is higher than 1000 ℃.With the residual volume of HPLC monitoring methylthiopropionaldehyde, when methylthiopropionaldehyde residual volume is less than 0.2%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 287.4g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 96%, prussic acid remnants 0.06%, moisture content 3%.
Embodiment 8
It is in 94.5% methylthiopropionaldehyde that prussic acid gas mixture II is passed into 223.3g massfraction, and to the damping fluid that adds a certain amount of sodium hydroxide and citric acid to form in mixed system, in logical prussic acid gas mixture process, keeping the pH of system is 5.0.Under normal pressure, react, controlling temperature of reaction is 45 ℃, and draft speed is 350L/min, and tail gas carries out burning disposal, and incineration temperature is higher than 1000 ℃.With the residual volume of HPLC monitoring methylthiopropionaldehyde, when methylthiopropionaldehyde residual volume is less than 0.5%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 287.4g, the content of 2-2-hydroxy-4-methylthio butyronitrile is 97%, prussic acid remnants 0.06%, moisture content 2%.
Embodiment 9
Under vigorous stirring, at 50 ℃, in reactor, add the sulfuric acid (1.57mol) that people 219.8g massfraction is 70%, in this temperature and vigorous stirring and cooling under add the synthetic 2-2-hydroxy-4-methylthio butyronitrile 279.54g of embodiment 3, control temperature of reaction at 50 ℃.Dropwise, at 65 ℃, react again 40 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then use 115g water diluting reaction content, the concentration that makes sulfuric acid is diluted to 46%(by original 70% and disregards organic moiety), be heated to 100 ℃ and stir 180 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction solution obtaining is processed with 71.3g strong aqua (massfraction 25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then mixture is proceeded in the distiller with water trap, to the methyl tertiary butyl ether that adds 700g in mixture, be heated to 65 ℃, in water trap, water directly reclaims water of condensation, organic phase is got back in distiller and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form.Filter collection salt, with the washing of 100g methyl tertiary butyl ether, the dry 208g massfraction that obtains is 99.5% ammonium sulfate.Merge methyl tertiary butyl ether filtrate, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 326.9g, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 95%, wherein monomer content is 80%, dimer and polymer are 15%, and moisture content is 5%.D, L-2-hydroxy-4-methylthiobutyric acid yield is that 99%(is in 3-methylthiopropionaldehyde).
Embodiment 10
Under vigorous stirring, at 50 ℃, in reactor, add the sulfuric acid (1.53mol) that people 231g massfraction is 65%, in this temperature and vigorous stirring and cooling under add the synthetic 2-2-hydroxy-4-methylthio butyronitrile 294.54g of embodiment 4, control temperature of reaction at 50 ℃.Dropwise, at 50 ℃, react again 60 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then use 102.7g water diluting reaction content, the concentration that makes its sulfuric acid is diluted to 45%(by original 65% and disregards organic moiety), be heated to 90 ℃ and stir 200 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction solution obtaining is processed with 58g strong aqua (massfraction 25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then mixture is proceeded in the distiller with water trap, to the methyl tertiary butyl ether that adds 700g in mixture, be heated to 55 ℃, in water trap, water directly reclaims water of condensation, organic phase is got back in distiller and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form.Filter collection salt, with the washing of 100g methyl tertiary butyl ether, the dry 203.0g massfraction that obtains is 99.5% ammonium sulfate.Merge methyl tertiary butyl ether filtrate, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 355.7g, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 92%, wherein monomer content is 80%, dimer and polymer are 12%, and moisture content is 8%.D, L-2-hydroxy-4-methylthiobutyric acid yield is that 99%(is in 3-methylthiopropionaldehyde).
Embodiment 11
Under vigorous stirring, at 50 ℃, in reactor, add the sulfuric acid (1.54mol) that people 201g massfraction is 75%, in this temperature and vigorous stirring and cooling under add the synthetic 2-2-hydroxy-4-methylthio butyronitrile 277.4g of embodiment 5, control temperature of reaction at 50 ℃.Dropwise, at 40 ℃, react again 100 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then use 141.6g water diluting reaction content, the concentration that makes its sulfuric acid is diluted to 44%(by original 75% and disregards organic moiety) left and right, be heated to 110 ℃ and stir 150 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction solution obtaining is processed with 69.5g strong aqua (massfraction 25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then mixture is proceeded in the distiller with water trap, to the methyl tertiary butyl ether that adds 650g in mixture, be heated to 60 ℃, in water trap, water directly reclaims water of condensation, organic phase is got back in distiller and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form.Filter collection salt, with the washing of 120g methyl tertiary butyl ether, the dry 204.7g massfraction that obtains is 99.5% ammonium sulfate.Merge methyl tertiary butyl ether filtrate, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 317.7g, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 96%, wherein monomer content is 79%, dimer and polymer are 17%, and moisture content is 4%.D, the yield of L-2-hydroxy-4-methylthiobutyric acid is that 99%(is in 3-methylthiopropionaldehyde).
Embodiment 12
Under vigorous stirring, at 50 ℃, in reactor, add the sulfuric acid (1.81mol) that people 221.2g massfraction is 80%, in this temperature and vigorous stirring and cooling under add the synthetic 2-2-hydroxy-4-methylthio butyronitrile 287.4g of embodiment 6, control temperature of reaction at 50 ℃.Dropwise, at 50 ℃, react again 40 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then use 163.5g water diluting reaction content, the concentration that makes its sulfuric acid is diluted to 46%(by original 80% and disregards organic moiety) left and right, be heated to 100 ℃ and stir 180 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction solution obtaining is processed with 103g strong aqua (massfraction 25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then mixture is proceeded in the distiller with water trap, to the methyl tertiary butyl ether that adds 750g in mixture, be heated to 70 ℃, in water trap, water directly reclaims water of condensation, organic phase is got back in distiller and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form.Filter collection salt, with the washing of 100g methyl tertiary butyl ether, the dry 240.1g massfraction that obtains is 99.5% ammonium sulfate.Merge methyl tertiary butyl ether filtrate, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 325.1g, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 96%, wherein monomer content is 82%, dimer and polymer are 14%, and moisture content is 4%.D, the yield of L-2-hydroxy-4-methylthiobutyric acid is that 99%(is in 3-methylthiopropionaldehyde).
Embodiment 13
The recovery water of condensation that embodiment 9 is obtained is for diluting 98% sulfuric acid.In reactor, add the water of condensation of the embodiment recovery of 63.2g, then slowly drip 98% vitriol oil of 158g, be mixed with 70% sulfuric acid 221.2g.
Under vigorous stirring, at 50 ℃, in reactor, add the sulfuric acid (1.58mol) that people's 221.2g massfraction obtained above is 70%, in this temperature and vigorous stirring and cooling under add the synthetic 2-2-hydroxy-4-methylthio butyronitrile 287.4g of embodiment 7, control temperature of reaction at 50 ℃.Dropwise, at 50 ℃, react again 40 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then the recovery water of condensation 115.4g diluting reaction content that embodiment 9 obtains, the concentration that makes its sulfuric acid is diluted to 46%(by original 70% and disregards organic moiety) left and right, be heated to 120 ℃ and stir 150 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction solution obtaining is processed with 71.7g strong aqua (massfraction 25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then mixture is proceeded in the distiller with water trap, to the methyl tertiary butyl ether that adds in mixture embodiment 9 to reclaim (poor amount is supplied with new methyl tertiary butyl ether) 750g, be heated to 75 ℃, in water trap, water directly reclaims water of condensation, organic phase is got back in distiller and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form.Filter collection salt, with the washing of 100g methyl tertiary butyl ether, the dry 209.6g massfraction that obtains is 99.5% ammonium sulfate.Merge methyl tertiary butyl ether filtrate, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 325.1g, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 96%, wherein monomer content is 80%, dimer and polymer are 16%, and moisture content is 4%.D, the yield of L-2-hydroxy-4-methylthiobutyric acid is that 99%(is in 3-methylthiopropionaldehyde).
Embodiment 14
The recovery water of condensation that embodiment 13 is obtained is for diluting 98% sulfuric acid.In reactor, add the water of condensation of the embodiment recovery of 63.9g, then slowly drip 98% vitriol oil of 159.6g, be mixed with 70% sulfuric acid 223.5g.
Under vigorous stirring, at 50 ℃, in reactor, add the sulfuric acid (1.60mol) that people's 223.5g massfraction obtained above is 70%, in this temperature and vigorous stirring and cooling under add the synthetic 2-2-hydroxy-4-methylthio butyronitrile 287.4g of embodiment 8, control temperature of reaction at 50 ℃.Dropwise, at 50 ℃, react again 40 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then the recovery water of condensation 116.4g diluting reaction content that embodiment 13 obtains, the concentration that makes its sulfuric acid is diluted to 46%(by original 70% and disregards organic moiety) left and right, be heated to 100 ℃ and stir 180 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction solution obtaining is processed with 73.9g strong aqua (massfraction 25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then mixture is proceeded in the distiller with water trap, to the methyl tertiary butyl ether that adds in mixture embodiment 13 to reclaim (poor amount is supplied with new methyl tertiary butyl ether) 750g, be heated to 65 ℃, in water trap, water directly reclaims water of condensation, organic phase is got back in distiller and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form.Filter collection salt, with the washing of 100g methyl tertiary butyl ether, the dry 211.8g massfraction that obtains is 99.5% ammonium sulfate.Merge methyl tertiary butyl ether filtrate, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 329.2g, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 96%, wherein monomer content is 81%, dimer and polymer are 15%, and moisture content is 4%.D, the yield of L-2-hydroxy-4-methylthiobutyric acid is that 99%(is in 3-methylthiopropionaldehyde).
Embodiment 15
As shown in Figure 1, D, L-2-hydroxy-4-methylthiobutyric acid production equipment comprises prussic acid synthetic tower 1, acid tower 2, reactor 3 and tripping device 4-pressure filter, fills massfraction and be 75%～90% sulfuric acid in described acid tower 2; Described reactor 3 is provided with pressure and temperature regulates supplementary unit, and with water trap equipment; The air outlet of prussic acid synthetic tower 1 is communicated with the inlet mouth of acid tower 2 by pipeline, and the air outlet of acid tower 2 is communicated with reactor 3 by being provided with the pipeline of throttling valve.
According to the synthetic prussic acid requirement of iS-One method, to prussic acid synthetic tower 1, send into raw material, react to obtain prussic acid gas mixture I, prussic acid gas mixture I passes into acid tower 2 and sloughs ammonia and water vapour, obtains prussic acid gas mixture II.Prussic acid gas mixture II is under throttle valve control, and the speed of 280L/min of take passes in the methylthiopropionaldehyde that in reactor 3,223.3kg massfraction is 94.5%, contains 2.2kg pyridine and 10kg water in methylthiopropionaldehyde.Under 0.15MPa, controlling temperature of reaction is 42 ℃, and tail gas absorbs with sodium hydroxide, with the residual volume of HPLC monitoring methylthiopropionaldehyde.When methylthiopropionaldehyde residual volume is less than 0.5%, be reaction end, can stop passing into.Be total to obtain weak yellow liquid 278.96kg, the content of 2-2-hydroxy-4-methylthio butyronitrile is 98%, prussic acid remnants 0.08%.
Under vigorous stirring, in 50 ℃, in reactor 3, add the sulfuric acid that people 219.8kg massfraction is 70%, add simultaneously, carry out coolingly, temperature is controlled at 50 ℃.Add complete, in 65 ℃, react again 40 minutes, by the residual quantity of HPLC monitoring 2-2-hydroxy-4-methylthio butyronitrile, when 2-2-hydroxy-4-methylthio butyronitrile is transformed into 2-2-hydroxy-4-methylthio butyramide completely, be reaction end, the transformation efficiency of 2-2-hydroxy-4-methylthio butyronitrile is more than 99%.Then use 115kg water diluting reaction content, the concentration that makes sulfuric acid is diluted to 46%(by original 70% and disregards organic moiety), be heated to 100 ℃ and stir 180 minutes, by HPLC monitoring 2-2-hydroxy-4-methylthio butyramide complete hydrolysis, become MHA.The reaction soln obtaining is processed with 71.3kg strong aqua (25%), and acid monoammonium sulfate is transformed into neutral ammonium sulfate.Then in mixture, add 700kg methyl tertiary butyl ether, be heated to 65 ℃ and distill, in water trap, water directly reclaims water of condensation, methyl tertiary butyl ether is got back in reactor 3 and is continued distillation band water, steams the water of condensation diluting water to sulfuric acid capable of circulation of collection until anhydrous.D now, L-2-hydroxy-4-methylthiobutyric acid is in methyl tertbutyl ethereal solution, and insoluble ammonium sulfate is separated out with crystallized form, through the separated filter collection of tripping device 4 ammonium sulfate, with 100kg methyl tertiary butyl ether washing, the dry 208kg massfraction that obtains is 99.5% ammonium sulfate.Merging methyl tertiary butyl ether filtrate returns in reactor 3, steam solvent methyl tertiary butyl ether (capable of circulation to production next time), obtain yellow oily residuum 326.5kg, for faint yellow, D, the content of L-2-hydroxy-4-methylthiobutyric acid is 95%, wherein monomer content is 79%, dimer and polymer are 16%, and moisture content is 5%.D, L-2-hydroxy-4-methylthiobutyric acid yield is that 99%(is in 3-methylthiopropionaldehyde).
Finally explanation is, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can modify or be equal to replacement technical scheme of the present invention, and not departing from aim and the scope of technical solution of the present invention, it all should be encompassed in the middle of claim scope of the present invention.
Claims (10)
1.D, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, is characterized in that: comprise the following steps:
A, take methane, ammonia and oxygen as raw material, adopt iS-One method composition principle, be prepared into prussic acid gas mixture I; Described prussic acid gas mixture I is processed to obtain prussic acid gas mixture II through deamination;
B, described prussic acid gas mixture II and methylthiopropionaldehyde, under the katalysis of alkali, fully react to obtain 2-2-hydroxy-4-methylthio butyronitrile system;
The reaction that is hydrolyzed under the existence of mineral acid of C, described 2-2-hydroxy-4-methylthio butyronitrile system, the reaction solution obtaining neutralizes through alkali, obtains D, the mixed system of L-2-hydroxy-4-methylthiobutyric acid and inorganic acid salt;
D, in described mixed system, add methyl tertiary butyl ether, redistillation dewaters, and obtains the methyl tertbutyl ethereal solution of inorganic acid salt and MHA, and inorganic acid salt is removed in separation, obtains filtrate; Described filtrate steams methyl tertiary butyl ether, obtains residue and is highly purified MHA.
2. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, is characterized in that: it is that prussic acid gas mixture I is passed into massfraction is that 75%～90% sulfuric acid carries out deamination processing that the deamination described in steps A is processed.
3. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, it is characterized in that: the methylthiopropionaldehyde described in step B is not purified methylthiopropionaldehyde, wherein contain the heavy constituent of the methylthiopropionaldehyde of massfraction 94.5%～96%, the light constituent of massfraction 3.5%～5.3% and massfraction 0.2%～0.5%; Described light constituent is thiomethyl alcohol, methyl alcohol, propenal and water; Described restructuring is divided into dipolymer and the trimer of methylthiopropionaldehyde.
4. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid ester, is characterized in that: the alkali described in step B is organic bases and/or mineral alkali; The consumption of described alkali is that the pH that maintains reaction system is 4.0～6.5.
5. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid ester, is characterized in that: in described step B, the mol ratio of prussic acid and methylthiopropionaldehyde is 1:1.0～1.05, reaction pressure is 0.09～0.5MPa, and temperature of reaction is 30～80 ℃.
6. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, is characterized in that: the alkali described in step C is one or more in alkalimetal oxide, oxyhydroxide, alkali metal carbon oxide compound, liquefied ammonia or ammoniacal liquor.
7. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, is characterized in that: in described step C, described mineral acid is sulfuric acid, and the mol ratio of 2-2-hydroxy-4-methylthio butyronitrile and sulfuric acid is 1:0.5～1; Described 2-2-hydroxy-4-methylthio butyronitrile successively obtains MHA through hydration reaction and hydrolysis reaction; During described hydration reaction, the massfraction of sulfuric acid is 50%～80%, and temperature is controlled at 40～70 ℃; During described hydrolysis reaction, thin up sulfuric acid is 40%～50% to the massfraction of sulfuric acid, and temperature is controlled at 90～130 ℃.
8. D according to claim 1, the preparation method of L-2-hydroxy-4-methylthiobutyric acid, is characterized in that: in described step D, the temperature that distillation dewaters is controlled at 55～75 ℃.
9. utilize D, L-2-hydroxy-4-methylthiobutyric acid production equipment is prepared D, the method of L-2-hydroxy-4-methylthiobutyric acid, it is characterized in that: described production equipment comprises prussic acid synthetic tower (1), acid tower (2), reactor (3) and tripping device (4), in described acid tower (2), fill massfraction and be 75%～90% sulfuric acid, described reactor (3) is provided with pressure and temperature regulates supplementary unit, the air outlet of prussic acid synthetic tower (1) is communicated with the inlet mouth of acid tower (2) by pipeline, the air outlet of acid tower (2) is communicated with reactor (3) by being provided with the pipeline of throttling valve,
A, take methane, ammonia and oxygen as raw material, adopt iS-One method composition principle, by prussic acid synthetic tower (1), prepare prussic acid gas mixture I; Described prussic acid gas mixture I passes into acid tower (2) and sloughs ammonia and water vapour, obtains prussic acid gas mixture II;
B, described prussic acid gas mixture II, under throttle valve control, pass in the methylthiopropionaldehyde in reactor (3) with the speed of 250～350L/min, under the katalysis of alkali, fully react to obtain 2-2-hydroxy-4-methylthio butyronitrile system;
Under C, vigorous stirring, in reactor (3), add sulfuric acid to mix with 2-2-hydroxy-4-methylthio butyronitrile system, successively process hydration reaction and hydrolysis reaction obtain the reaction solution of MHA; During described hydration reaction, the massfraction of sulfuric acid is 50%～80%, and temperature is controlled at 40～70 ℃; During described hydrolysis reaction, thin up sulfuric acid is 40%～50% to the massfraction of sulfuric acid, and temperature is controlled at 90～130 ℃; The reaction solution that obtains MHA neutralizes through alkali, obtains D, the mixed system of L-2-hydroxy-4-methylthiobutyric acid and vitriol;
D, in described mixed system, add methyl tertiary butyl ether, redistillation dewaters, and obtains the methyl tertbutyl ethereal solution of vitriol and MHA, through tripping device (4) separation, removes vitriol, obtains filtrate; Described filtrate is returned to reactor (3), steams methyl tertiary butyl ether, obtains residue and is highly purified MHA; The dilution to next step C sulfuric acid capable of circulation of the described water distilling out; The production to next step D capable of circulation of the described methyl tertiary butyl ether steaming.
10. the D that utilizes according to claim 12, L-2-hydroxy-4-methylthiobutyric acid production equipment is prepared D, and the method for L-2-hydroxy-4-methylthiobutyric acid, is characterized in that: described reactor (3) is also with water trap.
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| CN107243300A (en) * | 2017-05-17 | 2017-10-13 | 山东新和成氨基酸有限公司 | A kind of preparation facilities of cyanalcohol and preparation method thereof |
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| 张富林: "安氏法天气合成氢氰酸国内生产概况", 《天然气化工(C1 化学与化工)》 * |
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| CN107243300A (en) * | 2017-05-17 | 2017-10-13 | 山东新和成氨基酸有限公司 | A kind of preparation facilities of cyanalcohol and preparation method thereof |
| CN107628976A (en) * | 2017-09-27 | 2018-01-26 | 山东新和成氨基酸有限公司 | A kind of method of the methylmercapto butyric acid of 2 hydroxyl of continuous preparation 4 of cleaning |
| CN107628976B (en) * | 2017-09-27 | 2019-06-04 | 山东新和成氨基酸有限公司 | A kind of method of clean continuous preparation 2-Hydroxy-4-methylthiobutyric acid |
| ES2837130R1 (en) * | 2018-11-01 | 2023-02-24 | Zhejiang Nhu Co Ltd | Method and device for preparing 2-hydroxy-4-methylthiobutyric acid and intermediates thereof |
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| CN109456240B (en) * | 2018-11-09 | 2021-04-16 | 天宝动物营养科技股份有限公司 | Production method of powdery methionine hydroxy analogue with dispersion fluidity |
| CN115650890A (en) * | 2022-04-28 | 2023-01-31 | 宁夏紫光天化蛋氨酸有限责任公司 | Method for treating tail gas generated in production of 2-hydroxy-4-methylthiobutyronitrile |
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