Production of alkyl esters of unsaturated monocarboxylic acids

Claim 2

A CONTINOUS PROCESS FOR THE PRODUCTION OF A LOWER ALKYL ESTER OF AN ALPHA-BETA UNATURATED MONOCARBOXYLIC ACID IN WHICH ESTER THE ALCOHOL MOIETY CONTAINS FROM 2 TO 4 CARBON ATOMS AND IN WHICH ESTER THE ACID MOIETY CONTAINS 3 OR 4 CARBON ATOMS, WHICH PROCESS COMPRISES. A, IN A MASS TRANSFER ZONE TO WHICH A GASEOUS ALPHAMONOOLEFIN OF 2 TO 4 CARBON ATOMS IS SUPPLIED SO AS TO MAINTAIN AN AMOSPHERE OF SAID GASEOUS ALPHA-MONOOLEFIN AS A CONTINOUS PHASE, EFFECTING THE MASS TRANSFER OF SAID ALPHA-MONOOLEFIN INTO LIQUID DROPLETS OF A HEREAFTER DEFINED RECYLE STREAM RECYCLED FROM THE HEREAFTER DEFINED FIRST REACTION ZONE, SO AS TO OBTAIN AN ALPHAMONOOLEFIN ENRICHED LIQUID. B. IN A FIRST REACTION ZONE MIXING AND REACTING THE ALPHAMONOOLEFIN ENRICHED LIQUID SO OBTAINED IN SAID MASS TRANSFER ZONE WITH A SUBSTANTIALLY ANHYDROUS SULFURIC ACID MEDIUM, SAID SULFURIC ACID MEDIUM BEING SUBSUBSTANTIALLY COMPRISED OF THE RESIDUAL LIQUID RECYCLED FROM THE HEREAFTER DEFINED RECOVERY ZONE TOGETHER WITH MAKE-UP SULFURIC ACID, SAID FIRST REACTION ZONE BEING OPERATED AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 100* TO 160*C AND AT A PRESSURE OF ABOUT 100 TO 300 PSIG, C. WITHDRAWING A PORTION OF THE REACTION MIXTURE FROM SAID FIRST REACTION ZONE RECYCLING SUCH AS SAID RECYCLE STREAM TO THE SAID MASS TRANSFER ZONE. D. PASSING THE REACTION MIXTURE OBTAINED FROM SAID FIRST REACTION ZONE TO A SECOND REACTION ZONE, ADDING TO AND REACTING WITH SUCH REACTION MIXTURE OBTAINED IN SAID FIRST REACTION ZONE AN ANHYDROUS ALPHA-BETA UNSATURATED MONOCARBOXYLIC ACID CONTAINING THREE OR FOUR CARBON ATOMS, SAID SECOND REACTION ZONE BEING OPERATED AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 100* TO 150*C AND A PRESSURE WITHIN HE RANGE OF ABOUT 100 TO 300 PSIG, IN A RECOVERY ZONE TREATING THE EFFLUENT FROM SAID SECOND REACTION ZONE SO AS TO RECOVER SAID LOWER ALKYL ESTER OF THE ALPHA-BETA UNSATURATED MONOCARBOXYLIC ACID THEREFROM, AND F. RECYCLING AT LEAST A PORTION OF THE RESIDUAL LIQUID FROM SAID SEPARATION ZONE TO SAID FIRST REACTION ZONE. WHEREIN SAID PROCESS IS EFFECTED UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS AND WHEREIN SAID PROCESS THE RATE OF CIRCULATION AND RECIRCULATION OF THE VARIOUS STREAMS THEREIN IS SUCH THAT THE RESIDENCE TIME OF THE LIQUID REACTANTS INTHE LOOP COMPRISED OF SAID FIRST REACTION ZONE AND SAID MASS TRANSFER ZONE IS FROM 8 TO 20 MINUTES, AND SUCH THAT THE RESIDENCE TIME OF THE REACTANTS IN SAID SECOND REACTION ZONE IS FROM 9 TO 16 MINUTES.

Claim 3

The process of claim 1 wherein in said mass transfer zone there is sprayed from 0.6 to 2.0 volumes of liquid per volume of vapor space in said mass transfer zone per minute, wherein the partial pressure of ethylene in said mass transfer zone is maintained at at least 100 psig, wherein the temperature within said mass transfer zone is maintained within the range of about 100* to 160*C, and wherein there is recycled from said first reaction zone to said mass transfer Zone from 0.7 to 2.0 volumes of the average liquid volume maintained in said first reaction zone per minute.

Claim 4

The process of claim 1 wherein in said separation zone said lower alkyl ester is recovered by distillation of the portion of said effluent of second reaction zone passed to said separation zone under a vacuum below about 200mm Hg absolute, with a stillpot temperature within the range of about 100* to 170*C and a still head temperature of 28* to 45*C, said lower alkyl ester being recovered from the overheads of said distillation, and the bottoms of said distillation being said residual liquid which is recycled to the first reaction zone.

Claim 5

The process of claim 1 wherein said alpha monoolefin is ethylene, wherein said monocarboxylic acid is acrylic acid and wherein said lower alkyl ester is ethyl acrylate.

Claim 6

The process of claim 2 wherein said alpha monoolefin is ethylene, wherein said monocarboxylic acid is acrylic acid and wherein said lower alkyl ester is ethyl acrylate.

Claim 7

The process of claim 3 wherein said alpha monoolefin is ethylene, wherein said monocarboxylic acid is acrylic acid and wherein said lower alkyl ester is ethyl acrylate.

Claim 8

A continuous process for the production of ethyl acrylate from ethylene and acrylic acid, which process comprises: a. in a mass transfer zone maintained at a temperature within the range of 110* to 130*C and to which gaseous ethylene is supplied so as to maintain an atmosphere of said gaseous ethylene as a continuous phase, effecting the mass transfer of said ethylene into liquid droplets of a hereafter defined recycle stream recycled from the hereafter defined first reaction zone, so as to obtain an ethylene enriched liquid, the partial pressure of ethylene within said mass transfer zone being maintained at from 100 to 300 psig, b. in a first reaction zone mixing and reacting the ethylene enriched liquid so obtained in said mass transfer zone with a substantially anhydrous sulfuric acid medium, said sulfuric acid medium being substantially comprised of the residual liquid recycled from the hereafter defined recovery zone together with make-up sulfuric acid, said first reaction zone being operated at a temperature within the range of about 110* to 130*C, and at a pressure of about 100 to 300 psig, c. withdrawing a portion of the reaction mixture from said first reaction zone and recycling such as said recycle stream to the said mass transfer zone, there being recycled from 0.8 to 1.3 volumes of the average liquid volume in said first reaction zone recycled per minute to said mass transfer zone, d. passing the reaction mixture obtained from said first reaction zone to a second reaction zone, adding to and reacting with such reaction mixture obtained in said first reaction zone anhydrous acrylic acid, said second reaction zone being operated at a temperature within the range of about 110* to 130*C and a pressure within the range of about 130 to 300 psig, e. in a recovery zone treating the effluent from said second reaction zone so as to recover ethyl acrylate therefrom, and f. recycling at least a portion of the residual liquid from said separation zone to said first reaction zone; wherein said process is effected under substantially anhydrous conditions, wherein the rate of circulation and recirculation of the various streams therein is such that the residence time of the liquid reactants in the loop comprised of said first reaction zone and said mass transfer zonee is from 11 to 15 minutes, where the residence time of the reactants in said second reaction zone is from 11 to 13 minutes, and wherein there is sprayed in said mass transfer zone from 0.7 to 1.2 volumes of liquid per volume of vapor space in said mass transfer zone per minute.

Claim 9

A continuous process for the production of ethyl acrylate from ethylene and acrylic acid, which process comprises: a. in a mass transfer zone maintained at a temperature within the range of 110* to 130*C and to which gaseous ethylene is supplied so as to maintain an atmosphere of said gaseous ethylene as a continuous phase, effecting the mass transfer of said ethylene into liquid droplets of a hereafter defined recycle stream recycled from the hereafter defined first reaction zone, so as to obtain an ethylene enriched liquid, the partial pressure of ethylene within said mass transfer zone being maintained at from 100 to 300 psig, b. in a first reaction zone mixing and reacting the ethylene enriched liquid so obtained in said mass transfer zone with a substantially anhydrous sulfuric acid medium, said sulfuric acid medium being substantially comprised of the residual liquid recycled from the hereafter defined recovery zone together with make-up sulfuric acid, said first reaction zone being operated at a temperature within the range of about 110* to 130*C, and at a pressure of about 100 to 300 psig, c. withdrawing a portion of the reaction mixture from said first reaction zone and recycling such as said recycle stream to the said mass transfer zone, there being recycled from 0.8 to 1.3 volumes of the average liquid volume in said first reaction zone recycled per minute to said mass transfer zone, d. passing the reaction mixture obtained from said first reaction zone to a second reaction zone, adding to and reacting with such reaction mixture obtained in said first reaction zone anhydrous acrylic acid, said second reaction zone being operated at a temperature within the range of about 110* to 130*C and a pressure within the range of about 130 to 300 psig, e. in a recovery zone treating the effluent from said second reaction zone so as to recover ethyl acrylate therefrom, and f. recycling at least a portion of the residual liquid from said separation zone to said first reaction zone; wherein said process is effected under substantially anhydrous conditions, wherein the rate of circulation and recirculation of the various streams therein is such that the residence time of the liquid reactants in the loop comprised of said first reaction zone and said mass transfer zonee is from 11 to 15 minutes, where the residence time of the reactants in said second reaction zone is from 11 to 13 minutes, and wherein there is sprayed in said mass transfer zone from 0.7 to 1.2 volumes of liquid per volume of vapor space in said mass transfer zone per minute.

Claim 10

The process of claim 7 wherein in said separation zone said ethyl acrylate is recovered by distillation of the portion of said effluent of second reaction zone passed to said separation zone under a vacuum below about 200mm Hg absolute, with a stillpot temperature within the range of about 100* to 170*C and a still head temperature of 28 to 45*C, said ethyl acrylate being recovered from the overheads of said distillation, and the bottoms of said distillation being said residual liquid which is recycled to the first reaction zone.