Method for the continuous production of alkyl(meth)acrylates with multiple catalyst recycling
View Patent ↗The invention relates to an improved method for the continuous production of alkyl(methyl)acrylates by transesterification of methyl(meth)acrylate with alcohols that are heavy in comparison with methanol. A special processing technique makes it possible to obtain new levels of product quality. Very high space-time-overall yields can also be obtained. The invention is characterized by the multiple use of a homogeneous catalyst which thereby reduces the costs of auxiliary agents significantly.
1. A process for continuously preparing higher (meth)acrylic esters (C) in a plant comprising a reaction apparatus and a vacuum evaporation stage for receiving a bottom product remaining after separation of a highly pure ester product, the process comprising:
transesterifying methyl(meth)acrylate (A) with a higher alcohol (B) in the presence of a catalyst or catalyst mixture in the reaction apparatus;
dividing a bottom effluent from the vacuum evaporation stage into a first portion and a second portion; and
recycling the first portion to the reaction apparatus;
wherein dividing the bottom effluent from the vacuum evaporation stage comprises selecting a proportion of the bottom effluent that will constitute the first portion based on current catalyst activity.
2. A process for continuously preparing higher (meth)acrylic esters (C) in a plant comprising a reaction apparatus and a film evaporator for separating a highly pure ester product, the process comprising:
transesterifying methyl(meth)acrylate (A) with a higher alcohol (B) in the presence of a catalyst or catalyst mixture in the reaction apparatus;
dividing a bottom effluent from the film evaporator into a first portion and a second portion; and
recycling the first portion to the reaction apparatus;
wherein dividing the bottom effluent from the film evaporator comprises selecting a proportion of the bottom effluent that will constitute the first portion based on current catalyst activity.
3. A process for continuously preparing higher (meth)acrylic esters (C) in a plant comprising a reaction apparatus, a film evaporator for separating a highly pure ester product, and a vacuum evaporation stage for receiving a bottom product remaining after separation of a highly pure ester product, the process comprising:
transesterifying methyl(meth)acrylate (A) with a higher alcohol (B) in the presence of a catalyst or catalyst mixture in the reaction apparatus;
dividing a bottom effluent from the film evaporator into a first portion and a second portion;
recycling the first portion to the reaction apparatus;
dividing a bottom effluent of the vacuum evaporation stage into a third portion and a fourth portion; and
recycling the third portion to the reaction apparatus;
wherein:
dividing the bottom effluent from the film evaporator comprises selecting a proportion of the bottom effluent from the film evaporator that will constitute the first portion based on current catalyst activity; and
dividing the bottom effluent from the vacuum evaporation stage comprises selecting a proportion of the bottom effluent from the vacuum evaporation stage that will constitute the third portion based on current catalyst activity.
4. The process of claim 1 , wherein the higher alcohol comprises at least one member selected from the group consisting of n-butanol, isobutanol, and 2-ethylhexanol.
5. The process of claim 1 , wherein the catalyst used comprises a homogeneous catalyst.
6. The process according to claim 5 , wherein the catalyst comprises a titanate of the higher alcohol (B).
7. The process according to claim 1 , wherein the first portion comprises 1-95% by weight of the bottom effluent from the vacuum evaporation stage.
8. The process according to claim 7 , wherein the first portion comprises 40-90% by weight of the bottom effluent from the vacuum evaporation stage.
9. The process according to claim 8 , wherein the first portion comprises 60-85% by weight of the bottom effluent from the vacuum evaporation stage.
10. The process according to claim 2 , wherein the first portion comprises 1-95% by weight of the bottom effluent from the film evaporator.
11. The process according to claim 10 , wherein the first portion comprises 40-90% by weight of the bottom effluent from the film evaporator.
12. The process according to claim 11 , wherein the first portion comprises 60-85% by weight of the bottom effluent from the film evaporator.
13. The process according to claim 3 , wherein the first portion and the third portion together comprise 1-95% by weight of the bottom effluents from the film evaporator and the vacuum evaporation stage.
14. The process according to claim 13 , wherein the first portion and the third portion together comprise 40-90% by weight of the bottom effluents from the film evaporator and the vacuum evaporation stage.
15. The process according to claim 14 , wherein the first portion and the second portion together comprises 60-85% by weight of the bottom effluents from the film evaporator and the vacuum evaporation stage.
16. The process of claim 2 , wherein the higher alcohol comprises at least one member selected from the group consisting of n-butanol, isobutanol, and 2-ethylhexanol.
17. The process of claim 3 , wherein the higher alcohol comprises at least one member selected from the group consisting of n-butanol, isobutanol, and 2-ethylhexanol.
18. The process of claim 2 , wherein the catalyst comprises a homogeneous catalyst.
19. The process of claim 3 , wherein the catalyst comprises a homogeneous catalyst.
20. A process for continuously preparing higher (meth)acrylic esters (C) in a plant comprising a reaction apparatus and a vacuum evaporation stage for receiving a bottom product remaining after separation of a highly pure ester product, the process comprising:
transesterifying methyl(meth)acrylate (A) with a higher alcohol (B) in the presence of a catalyst or catalyst mixture in the reaction apparatus;
dividing a bottom effluent from the vacuum evaporation stage into a first portion and a second portion; and
recycling the first portion to the reaction apparatus;
wherein the first portion is recycled directly to the reaction apparatus.