CN103130672B - Method for preparing methacrylamide - Google Patents
Method for preparing methacrylamide Download PDFInfo
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- CN103130672B CN103130672B CN201310104387.0A CN201310104387A CN103130672B CN 103130672 B CN103130672 B CN 103130672B CN 201310104387 A CN201310104387 A CN 201310104387A CN 103130672 B CN103130672 B CN 103130672B
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Abstract
The invention discloses a method for preparing methacrylamide. The method comprises the following steps: carrying out concentrated sulfuric acid hydrolysis, dehydration and the like on acetone cyanohydrin as a main raw material to generate methacrylamide sulfate; neutralizing methacrylamide sulfate by ammonia or ammonia water; recycling a neutralized centrifugal mother solution; and washing an ammonium sulfate-containing methacrylamide wet product by using an organic solvent and purifying the ammonium sulfate-containing methacrylamide wet product twice through recrystallization to obtain a methacrylamide pure product, wherein the recycled organic solvent can be repeatedly used, and a recrystallized mother solution can be repeatedly used as well. As a novel process route is adopted and the mother solution can be repeatedly used, the emission of saliferous and acidiferous wastewater can be greatly reduced, the pollution of the waste water to an environment is avoided, the salvation of methacrylamide in the mother solution is reduced, the yield of methacrylamide is improved and reaches more than 92%, and methacrylamide with the content of more than 99% is obtained.
Description
Technical field
The present invention relates to the synthesis technical field of Methacrylamide, particularly a kind of method of producing Methacrylamide.
Background technology
Methacrylic acid amino is mainly used in silk weighting agent, fiber levelling agent, moisture adsorbent, tackiness agent and static inhibitor, is also used as cement additire, grout additive, leatheroid additive etc.The quality of Methacrylamide is decided by the rate of body weight gain of Methacrylamide in silk weighting process, and producing Methacrylamide has methacrylic eyeball hydrolysis method, acetone cyanohydrin sour water solution, methyl methacrylate ammonolysis process and methacrylic acid and ammonia synthesis.Industrial main employing acetone cyanohydrin hydrolysis method, domesticly still rests on the lab scale stage at present, and product purity reaches 95%, and productive rate often only has about 60% ~ 70%.Operational path in the past produces Methacrylamide (comprising methyl methacrylate and methacrylic acid) can produce a large amount of waste water, owing to containing a certain amount of Methacrylamide and methacrylic acid in waste water, along with the waste water shelf-time is long, a large amount of polymkeric substance is produced in waste water, the discharge of waste water, to environment, is also a kind of loss to product.
Summary of the invention
In view of this, the invention provides a kind of method of producing Methacrylamide, the discharge of saliferous acid-bearing wastewater can be greatly reduced, and improve the productive rate of Methacrylamide.
The method of production Methacrylamide of the present invention, comprises the following steps:
1) acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester;
2) α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, and dehydration generates methacrylamide sulfate;
3) with ammonia or ammonia neutralization methacrylamide sulfate, its sulfuric acid is made to be converted into ammonium sulfate completely;
4) neutralization after, crystallisation by cooling, centrifugal go out crystal, Recycling Mother Solution is got back in step 3) He in system and is used as solvent, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate;
5) by the Methacrylamide wet product of organic solvent washing liquid containing ammonium sulfate, the organic solvent containing Methacrylamide and ammonium sulfate solids after centrifugal, is obtained;
6) organic solvent containing Methacrylamide concentrates, and reclaim organic solvent, the organic solvent of recovery recycles, and the crystal of precipitation is Methacrylamide work in-process;
7) Methacrylamide work in-process heating for dissolving, after activated carbon decolorizing, cooling recrystallization, crystal is dried and is obtained Methacrylamide sterling, and recrystallization mother liquor is circulated back to step 7) as recrystallization solvent.
The reaction formula of described step 1) is:
Its preferred processing parameter is: the mass ratio of acetone cyanohydrin and the vitriol oil is 1:1.1 ~ 1.7, and the mass concentration of the vitriol oil is 98% ~ 100.3%, and acetone cyanohydrin and the vitriol oil take two mode dripped to add reaction system, and temperature of reaction is 60 DEG C ~ 100 DEG C; Can add stopper in reaction system, stopper is one or several of Resorcinol, thiodiphenylamine and copper sulfate, and the quality of stopper is 0.1% ~ 0.5% of acetone cyanohydrin.
Described step 2) reaction formula be:
Its preferred processing parameter is: temperature of reaction is 100 DEG C ~ 150 DEG C.
The reaction formula of described step 3) is:
Its preferred processing parameter is: in dropping to after methacrylamide sulfate being cooled to 90 DEG C ~ 100 DEG C and in system, simultaneously toward in system in pass into ammoniacal liquor or ammonia, temperature of reaction is 0 DEG C ~ 60 DEG C, in after neutralization and the pH value of system be 5.5 ~ 7.0.
The preferred processing parameter of described step 4) is: Tc is 0 DEG C ~ 25 DEG C.
The preferred processing parameter of described step 5) is: the mass ratio of organic solvent and Methacrylamide is 1 ~ 3:1, organic solvent be selected from methyl alcohol, ethanol, Virahol, n-propyl alcohol, propyl carbinol, toluene, tetrahydrofuran (THF), trieline, ethylene dichloride and m-xylene one or several.
The preferred processing parameter of described step 7) is: the mass ratio of recrystallization solvent and Methacrylamide is 1:2 ~ 3, and heating for dissolving temperature is 50 DEG C ~ 70 DEG C, and recrystallization temperature is 0 DEG C ~ 25 DEG C.
In described step 3), in first time and time, in and the solvent of system be water, the quality of water is 3 ~ 5 times of the quality of ammonia; Second and later time in and time, in and the solvent of system be the mother liquor of step 4) cyclically utilizing.
In described step 7), during first time recrystallization, recrystallization solvent is water; Second and later time recrystallization time, recrystallization solvent is the recrystallization mother liquor of step 7) cyclically utilizing.
Beneficial effect of the present invention is: the present invention take acetone cyanohydrin as main raw material, through effects such as vitriol oil hydrolysis, dehydrations, generate methacrylamide sulfate, methacrylamide sulfate is through ammonia or ammonia neutralization, centrifuge mother liquor recycled after neutralization, and the Methacrylamide wet product of liquid containing ammonium sulfate is through twice purification of organic solvent washing and recrystallization, obtain Methacrylamide sterling, and the organic solvent reclaimed can recycled, and recrystallization mother liquor is recycled also.The present invention adopts new operational path, enable mother liquor recycled, thus greatly reduce the discharge of saliferous acid-bearing wastewater, avoid the pollution of waste water to environment, and decrease the dissolving of Methacrylamide in mother liquor, improve the productive rate of Methacrylamide, obtain the Methacrylamide of content more than 99%, yield reaches more than 92%.
The present invention be a kind of less energy-consumption, eco-friendly, reduce production cost, reduce investment operational path, be specially adapted to industrial scale, continuous prodution, especially reduce discharge of wastewater, increase yield successful.
Accompanying drawing explanation
In order to make the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail, wherein:
Fig. 1 is process flow sheet of the present invention.
Embodiment
Hereinafter with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.
embodiment 1
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2193 kilograms, water in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, just completely neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2640 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2243 kilograms, the content of its Methacrylamide is 37%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 883 kilograms, and it is 94% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then totally 441 kilograms, the water (in Methacrylamide) of 0.5 times of quality is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (24 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 780 kilograms, and purity reaches more than 99%, and yield 92%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 499 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
embodiment 2(Recycling Mother Solution applies mechanically 1)
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2640 kilograms, the mother liquor of embodiment 1 step 4) gained in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable completely just; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2745 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2240 kilograms, the content of its Methacrylamide is 39%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 919 kilograms, and it is 95% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then the recrystallization mother liquor 499 kilograms of embodiment 1 step 7) gained is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (26 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 815 kilograms, and purity reaches more than 99%, and yield 95%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 511 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
embodiment 3(Recycling Mother Solution applies mechanically 2)
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2745 kilograms, the mother liquor of embodiment 2 step 4) gained in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable completely just; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2640 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2889 kilograms, the content of its Methacrylamide is 33%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 1003 kilograms, and it is 95% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then the recrystallization mother liquor 511 kilograms of embodiment 2 step 7) gained is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (28 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 851 kilograms, and purity reaches more than 99%, and yield 99.1%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 489 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
embodiment 4(Recycling Mother Solution applies mechanically 3)
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2640 kilograms, the mother liquor of embodiment 3 step 4) gained in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable completely just; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2740 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2343 kilograms, the content of its Methacrylamide is 37%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 903 kilograms, and it is 96% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then the recrystallization mother liquor 489 kilograms of embodiment 3 step 7) gained is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (26 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 824 kilograms, and purity reaches more than 99%, and yield 96%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 500 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
embodiment 5(Recycling Mother Solution applies mechanically 4)
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2740 kilograms, the mother liquor of embodiment 4 step 4) gained in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable completely just; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2544 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2543 kilograms, the content of its Methacrylamide is 34%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 920 kilograms, and it is 94% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then the recrystallization mother liquor 500 kilograms of embodiment 4 step 7) gained is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (28 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 820 kilograms, and purity reaches more than 98.5%, and yield 95%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 520 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
embodiment 6(Recycling Mother Solution applies mechanically 5)
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2544 kilograms, the mother liquor of embodiment 5 step 4) gained in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable completely just; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2480 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2443 kilograms, the content of its Methacrylamide is 35%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 910 kilograms, and it is 94% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then the recrystallization mother liquor 520 kilograms of embodiment 5 step 7) gained is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (27 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 815 kilograms, and purity reaches more than 99%, and yield 95%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 550 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
embodiment 7(Recycling Mother Solution applies mechanically 6)
1) by the vitriol oil (1403 kilograms), acetone cyanohydrin (850 kilograms) through spinner-type flowmeter, according to 1.65:1(mass ratio) ratio drops in reactor, acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester, because reaction is now thermopositive reaction, so open cooling system, a pot interior reaction temperature is made to remain on 90 DEG C, resultant overflows from reactor overflow port, enters tubular reactor;
2) above-mentioned reactant continues and vitriol oil generation chemical reaction in tubular reactor, α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, dehydration generates methacrylamide sulfate, this reaction is thermo-negative reaction, with being steam heated to 130 DEG C, because temperature is too low, chemical reaction is incomplete, temperature is too high, easily causes polymerization or charing, so control temperature is key factor; In order to make reaction be tending towards complete, resultant enters warmer, and holding temperature controls at about 130 DEG C; After material proceeds to acid amides susceptor, sampling analysis, the content of its Methacrylamide is more than 34%, and the productive rate of Methacrylamide is 99%;
3) above-mentioned methacrylamide sulfate is cooled to 100 DEG C, keeps the mobility of methacrylamide sulfate; In and add 2480 kilograms, the mother liquor of embodiment 6 step 4) gained in still, be cooled to 10 DEG C, then slowly drip methacrylamide sulfate, pass into ammonia simultaneously, pass into the total amount of ammonia with sulphur acid meter, neutralisation of sulphuric acid is converted into ammonium sulfate and is advisable completely just; Because neutralization reaction is thermopositive reaction, in and still inner coil pipe pass into water of condensation, control temperature of reaction be no more than 60 DEG C, temperature is too high, and Methacrylamide hydrolysis reaction can occur;
4), after neutralization, be cooled to about 10 DEG C, crystal is separated out completely, then centrifugal, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate, obtains 2440 kilograms, mother liquor, and mother liquor is circulated back in step 3) He in system next time and is used as solvent;
5) by the Methacrylamide wet product of liquid containing ammonium sulfate totally 2646 kilograms, the content of its Methacrylamide is 34%, add the methanol wash of 1122 kilograms, violent stirring at room temperature is dissolved, after Methacrylamide dissolves completely, centrifugal, obtain the methanol solution containing Methacrylamide and ammonium sulfate solids;
6) methanol solution containing Methacrylamide concentrates, and reclaims methyl alcohol, and the methanol loop of recovery uses, and after cooling, the crystal of precipitation is Methacrylamide work in-process, and half-finished quality is 957 kilograms, and it is 94% that work in-process contain Methacrylamide;
7) Methacrylamide work in-process add in crystallization kettle, then the recrystallization mother liquor 550 kilograms of embodiment 6 step 7) gained is added, be heated to 60 DEG C dissolve completely to Methacrylamide, the gac (28 kilograms) then adding 3% quality (in Methacrylamide) decolours; After suction filtration gac, filtrate is cooled to 10 DEG C of recrystallizations, and crystal is dried and obtained Methacrylamide sterling 837 kilograms, and purity reaches more than 98.5%, and yield 97%(is in acetone cyanohydrin); Obtain recrystallization mother liquor 604 kilograms, recrystallization mother liquor is circulated back to step 7) next time and is used as recrystallization solvent.
In described step 3), in first time and time, in and the solvent of system be water, the quality of water is 3 ~ 5 times of the quality of ammonia; Second and later time in and time, in and the solvent of system be the mother liquor of step 4) cyclically utilizing; In case of no particular description, mother liquor to go down by recycled completely, the number of times applied mechanically is not limited to above-mentioned number of times, mother liquor is along with the number of times increase of applying mechanically, the water yield can reduce to some extent, in order to guarantee that neutralization is stirred fully, suitably can add water in mother liquor, the water yield added is as the criterion so that system can be made fully to stir.In and methacrylamide sulfate time, preferred ammonia; As with ammonia neutralization, when mother liquor is used for applying mechanically next time, need the amount of extraction 30% ~ 50%.
In described step 7), during first time recrystallization, recrystallization solvent is water; Second and later time recrystallization time, recrystallization solvent is the recrystallization mother liquor of step 7) cyclically utilizing; In case of no particular description, recrystallization mother liquor to go down by recycled completely, and the number of times applied mechanically is not limited to above-mentioned number of times, and recrystallization mother liquor can according to the content of ammonium sulfate when applying mechanically, suitably can add water, adding the water yield can according to the solubleness of ammonium sulfate 10 DEG C time.
What finally illustrate is, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although by referring to the preferred embodiments of the present invention, invention has been described, but those of ordinary skill in the art is to be understood that, various change can be made to it in the form and details, and not depart from the spirit and scope of the present invention that appended claims limits.
Claims (5)
1. produce a method for Methacrylamide, it is characterized in that: comprise the following steps:
1) acetone cyanohydrin and vitriol oil effect, hydrolysis generates α-formamido-sec.-propyl hydrogen sulfuric acid ester; The mass ratio of described acetone cyanohydrin and the vitriol oil is 1:1.1 ~ 1.7, and the mass concentration of the vitriol oil is 98% ~ 100.3%, and acetone cyanohydrin and the vitriol oil take two mode dripped to add reaction system, and temperature of reaction is 60 DEG C ~ 100 DEG C;
2) α-formamido-sec.-propyl hydrogen sulfuric acid ester is under vitriol oil effect, and dehydration generates methacrylamide sulfate; Described temperature of reaction is 100 DEG C ~ 150 DEG C;
3) with ammonia or ammonia neutralization methacrylamide sulfate, its sulfuric acid is made to be converted into ammonium sulfate completely; Concrete operations in dropping to after methacrylamide sulfate is cooled to 90 DEG C ~ 100 DEG C and in system, simultaneously toward in and pass into ammoniacal liquor or ammonia in system, temperature of reaction is 0 DEG C ~ 60 DEG C, is 5.5 ~ 7.0 with the pH value of system in after neutralization;
4) neutralization after, crystallisation by cooling, centrifugal go out crystal, Recycling Mother Solution is got back in step 3) He in system and is used as solvent, and crystal is the Methacrylamide wet product of liquid containing ammonium sulfate;
5) by the Methacrylamide wet product of organic solvent washing liquid containing ammonium sulfate, the organic solvent containing Methacrylamide and ammonium sulfate solids after centrifugal, is obtained;
6) organic solvent containing Methacrylamide concentrates, and reclaim organic solvent, the organic solvent of recovery recycles, and the crystal of precipitation is Methacrylamide work in-process;
7) Methacrylamide work in-process heating for dissolving, after activated carbon decolorizing, cooling recrystallization, crystal is dried and is obtained Methacrylamide sterling, and recrystallization mother liquor is circulated back to step 7) as recrystallization solvent;
In described step 3), in first time and time, in and the solvent of system be water, the quality of water is 3 ~ 5 times of the quality of ammonia; Second and later time in and time, in and the solvent of system be the mother liquor of step 4) cyclically utilizing;
In described step 7), during first time recrystallization, recrystallization solvent is water; Second and later time recrystallization time, recrystallization solvent is the recrystallization mother liquor of step 7) cyclically utilizing.
2. the method for production Methacrylamide according to claim 1, it is characterized in that: in described step 1), add in reaction system and have stopper, stopper is one or several of Resorcinol, thiodiphenylamine and copper sulfate, and the quality of stopper is 0.1% ~ 0.5% of acetone cyanohydrin.
3. the method for production Methacrylamide according to claim 1, is characterized in that: in described step 4), and Tc is 0 DEG C ~ 25 DEG C.
4. the method for production Methacrylamide according to claim 1, it is characterized in that: in described step 5), the mass ratio of organic solvent and Methacrylamide is 1 ~ 3:1, organic solvent be selected from methyl alcohol, ethanol, Virahol, n-propyl alcohol, propyl carbinol, toluene, tetrahydrofuran (THF), trieline, ethylene dichloride and m-xylene one or several.
5. the method for production Methacrylamide according to claim 1, is characterized in that: in described step 7), and the mass ratio of recrystallization solvent and Methacrylamide is 1:2 ~ 3, and heating for dissolving temperature is 50 DEG C ~ 70 DEG C, and recrystallization temperature is 0 DEG C ~ 25 DEG C.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3502719A (en) * | 1965-10-02 | 1970-03-24 | Roehm & Haas Gmbh | Preparation of methacrylamide sulfate |
| US3558695A (en) * | 1966-06-29 | 1971-01-26 | Mitsubishi Rayon Co | Process for preparing methacryl amidemethacrylic acid mixtures |
| CN101827808A (en) * | 2007-10-18 | 2010-09-08 | 赢创罗姆有限公司 | Method for amidating of nitrile in the presence of sulfuric acid |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3502719A (en) * | 1965-10-02 | 1970-03-24 | Roehm & Haas Gmbh | Preparation of methacrylamide sulfate |
| US3558695A (en) * | 1966-06-29 | 1971-01-26 | Mitsubishi Rayon Co | Process for preparing methacryl amidemethacrylic acid mixtures |
| CN101827808A (en) * | 2007-10-18 | 2010-09-08 | 赢创罗姆有限公司 | Method for amidating of nitrile in the presence of sulfuric acid |
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| Title |
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| 甲基丙烯酰胺合成工艺的改进;胡华;《江苏化工》;19971231;第25卷;第26-27 * |
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