Process for making acrylamide

Claim 2

A PROCESS FOR CATLYTICALLY HYDROLYZING ACRYLONITRILE TO ACRYLAMIDE UNDER LIQUID PHASE CONDITIONS COMPRISING CONTINUOUSLY PASSING SEQUENTIALLY THROUGH AT LEAST TWO TUBLAR REACTION ZONES IN A PLUG FLOW MANNER A LIQUID REACTANT FEED COMPOSITION COMPRISING FROM ABOUT 25 TO 75 WT.% ACRYLONITRILE AND FROM ABOUT 25 TO 75 WT. % WATER ON A 100 WT.% TOTAL REACTANT FEED COMPOSITION BASIS, EACH ONE OF SAID REACTION ZONES A. CONTAINING A FIXED CATALYST BED, B. THE CATALYST COMPRISING EACH OF SAID BEDS BEING CHARACTERIZED BY HAVING AN INITIAL ACTIVITY OF AT LEAST ABOUT 0.25 BASED UPON A STARTING FEED COMPOSITION OF 35 WT. % ACRYLONITRILE AND 64 WT. % WATER, TOTAL COMPOSITION BASIS, USING AN ARITHMETIC MEAN CATALYST BED TEMPERATURE OF 210*F., A CATALYST BED VOLUME OF ABOUT 50 CUBIC INCHES AND AN EVALUATION WEIGHT HOURLY SPACE VELOCITY WHICH IS SUFFICIENT TO PRODUCE 80 PERCENT CONVERSION OF ACRYLONITRILE TO ACRYLAMIDE, SAID PROCESS A''. BEING CONDUCTED SUBSTANTIALLY ISOTHERMALLY AT TEMPERATURES IN THE RANGE OF FROM ABOUT 100* TO 300*F, AND B''. HAVING A SYSTEM WEIGHT HOURLY SPACE VELOCITY IN THE RANGE OF FROM ABOUT 0.1 TO 10 HOURS -1, THE INTERRELATIONSHIP BETWEEN SAID SYSTEM WEIGHT HOURLY SPACE VELOCITY AND THE TEMPERATURE, RESPECTIVELY, IN EACH ON OF SAID REACTION ZONES BEING SUCH THAT THE PERCENTAGE CONVERSION OF ACRYLONTRILE TO ACRYAMIDE IN EACH ONE OF SUCH REACTION ZONES RANGES FROM ABOUT 0.5 TO 1.5 TIMES SAID TOTAL SYSTEM CONVERSION DIVIDED BY THE TOTAL NUMBER OF SAID REACTION ZONES.

Claim 3

The process of claim 1 wherein there are two of said reaction zones.

Claim 4

The process of claim 1 wherein there are three of said reaction zones.

Claim 5

The process of claim 1 wherein there are four of said reaction zones.

Claim 6

The process of claim 1 wherein said catalyst is in the form of particles ranging in size from about 0.01 to 0.49 inch.

Claim 7

The process of claim 1 wherein said catalyst is in the form of particles ranging in size from about 0.02 to 0.3 inch.

Claim 8

The process of claim 1 wherein said catalyst is a coppercontaining catalyst.

Claim 9

The process of claim 7 wherein said catalyst is a Raney copper catalyst.

Claim 10

The process of claim 1 wherein said catalyst has such an initial activity of from about 0.25 to 2.

Claim 11

The process of claim 1 wherein said catalyst has such an initial activity of from about 0.45 to 1.5.

Claim 12

The process of claim 1 wherein said system weight hourly space velocity ranges from about 0.5 to 2.

Claim 13

The process of claim 1 wherein said temperatures range from about 150* to 260*F, wherein each of said reaction zones is maintained at a substantially constant temperature, and wherein each successive reaction zone is maintained at a higher temperature than the preceding reaction zone.

Claim 14

The process of claim 1 wherein said total system conversion is at least about 60 percent.

Claim 15

The process of claim 1 wherein the product liquid mixture is subjected to stripping to recover therefrom unreacted acrylonitrile.

Claim 16

The process of claim 14 wherein said recovered acrylonitrile is recycled back to at least one of said reaction zones.

Claim 17

The process of claim 14 wherein said recovered acrylonitrile is recycled back to the first of said reaction zones in admixture with said feed composition.

Claim 18

The process of claim 14 wherein said stripping is carried out at temperatures ranging from about 100* to 212*F. at pressures ranging from about 50 to 760 mm Hg.

Claim 19

The process of claim 14 wherein the so stripped product comprises on a 100 weight percent basis from about 40 to 60 weight percent acrylamide and from about 40 to 60 weight percent water.

Claim 20

The process of claim 1 wherein said interrelationship between said system weight hourly space velocity and said isothermal temperature ranges from about 0.7 to 1.3.

Claim 21

The process of claim 1 wherein the total system conversion of starting acrylonitrile to acrylamide is at least about 75 percent.

Claim 22

A process for hydrolyzing with a fixed bed catalyst acrylonitrile to acrylamide comprising continuously passing sequentially through three tubular reaction zones substantially isothermally under liquid phase conditions at a system weight hourly space velocity ranging from about 0.1 to 10 hours 1 a reactant composition comprising from about 25 to 75 weight percent acrylonitrile and from about 25 to 75 weight percent water on a 100 weight percent total composition basis, there being a conversion of starting acrylonitrile to acrylamide after passing through said first reaction zone of from about 15 to 45 percent, a conversion of starting acrylonitrile to acrylamide after Passing through second said reaction zone of about 35 to 65 percent, and a conversion of starting acrylonitrile to acrylamide after passing through said third reaction zone of from about 65 to 99 percent. each of said reaction zones containing a bed of Raney copper catalyst which has an initial catalytic activity of at least about 0.25 based upon a starting feed composition of 35 weight percent acrylonitrile and 65 weight percent water, total composition basis, an arithmetic mean catalyst bed temperature of 210*F, using a catalyst bed volume of about 50 cubic inches and an evaluation weight hourly space velocity which is sufficient to produce 80 percent conversion of acrylonitrile to acrylamide, said first reaction zone being maintained at a temperature ranging from about 100* to 250*F., said second reaction zone being maintained at a temperature ranging from about 100* to 250*F., and said third reaction zone being maintained at a temperature ranging from about 120* to 300*F, said process resulting in a total system conversion of starting acrylonitrile to acrylamide of at least about 60 percent, the interrelationship between the system weight hourly space velocity and the temperature, respectively, in each one of said reaction zones being such that the percentage conversion of acrylonitrile to acrylamide in each one of such reaction zones ranges from about 0.5 to 1.5 times said total system conversion divided by the total number of said reaction zones.

Claim 23

A process for hydrolyzing with a fixed bed catalyst acrylonitrile to acrylamide comprising continuously passing sequentially through three tubular reaction zones substantially isothermally under liquid phase conditions at a system weight hourly space velocity ranging from about 0.1 to 10 hours 1 a reactant composition comprising from about 25 to 75 weight percent acrylonitrile and from about 25 to 75 weight percent water on a 100 weight percent total composition basis, there being a conversion of starting acrylonitrile to acrylamide after passing through said first reaction zone of from about 15 to 45 percent, a conversion of starting acrylonitrile to acrylamide after Passing through second said reaction zone of about 35 to 65 percent, and a conversion of starting acrylonitrile to acrylamide after passing through said third reaction zone of from about 65 to 99 percent. each of said reaction zones containing a bed of Raney copper catalyst which has an initial catalytic activity of at least about 0.25 based upon a starting feed composition of 35 weight percent acrylonitrile and 65 weight percent water, total composition basis, an arithmetic mean catalyst bed temperature of 210*F, using a catalyst bed volume of about 50 cubic inches and an evaluation weight hourly space velocity which is sufficient to produce 80 percent conversion of acrylonitrile to acrylamide, said first reaction zone being maintained at a temperature ranging from about 100* to 250*F., said second reaction zone being maintained at a temperature ranging from about 100* to 250*F., and said third reaction zone being maintained at a temperature ranging from about 120* to 300*F, said process resulting in a total system conversion of starting acrylonitrile to acrylamide of at least about 60 percent, the interrelationship between the system weight hourly space velocity and the temperature, respectively, in each one of said reaction zones being such that the percentage conversion of acrylonitrile to acrylamide in each one of such reaction zones ranges from about 0.5 to 1.5 times said total system conversion divided by the total number of said reaction zones.

Claim 24

The process of claim 21 wherein said reactant composition after passing through said third reaction zone is subjected to stripping to remove therefrom substantially completely all unreacted acrylonitrile thereby to produce an aqueous solution of from about 40 to 60 weight percent acrylamide with the balance up to 100 weight percent being water.

Claim 25

The process of claim 22 wherein acrylonitrile so removed is recycled to said reactant composition, as fed to said first zone.

Claim 26

The process of claim 21 wherein the order of respective ones of said reaction zones is changed in the sequence of such passage 0f said reactant composition therethrough, thereby permitting rates of deactivation of catalyst in individual ones of said reaction zones to be minimized.

Claim 27

The process of claim 21 wherein said system weight hourly space velocity ranges from about 0.5 to 2 hours 1.

Claim 28

The process of claim 21 wherein said reactant composition comprises from about 30 to 40 weight percent acrylonitrile and from about 60 to 70 weight percent water, and said conversion of starting acrylonitrile to acrylamide after passing through said first reaction zone of from about 20 to 40 percent, said converstion of starting acrylonitrile to acrylamide after passing through said second reaction zone of from about 50 to 60 percent, and said conversion of starting acrylonitrile to acrylamide after passing through said third reaction zone of from about 70 to 90 percent.

Claim 29

The process of claim 21 wherein, in each of said reaction zones, said Raney copper has such an initial catalytic activity of from about 0.45 to 1.5

Claim 30

The process of claim 21 wherein, in each of said reaction zones, said catalyst is in the form of particles ranging in size from about 0.01 to 0.49 inch.

Claim 31

The process of claim 21 wherein said catalyst is in the form of particles ranging in size from about 0.02 to 0.3 inch.

Claim 32

The process of claim 21 wherein said catalyst is a copper-containing catalyst.

Claim 33

The process of claim 30 wherein said catalyst is a Raney copper catalyst.

Claim 34

The process of claim 21 wherein said total system conversion is at least about 75 percent.

Claim 35

The process of claim 21 wherein said interrelationship bEtween said system weight hourly space velocity and temperature ranges from about 0.7 to 1.3.

Claim 36

IN AN IMPROVED PROCESS FOR HYDROLYZING WITH A FIXED BED CATALYST ACRYLONITRILE TO ACRYLAMIDE OF THE TYPE EMPLOYING THREE TUBULAR REACTION ZONES THROUGH WHICH IN NORMAL PROCESS OPERATION A REACTANT COMPOSITION COMPRISING FROM ABOUT 25 TO 75 WEIGHT PERCENT ACRYLONITRILE AND FROM ABOUT 25 TO 75 WEIGHT PERCENT WATER ON A 100 WEIGHT PERCENT TOTAL COMPOSITION BASIS IS PASSED SEQUENTIALLY, SUBSTANTIALLY, ISOTHERMALLY, AND UNDER LIQUID PHASE CONDITIONS, EACH OF SAID REACTION ZONES CONTAINING A BED OF RANEY COPPER CATALYST WHICH HAS AN INITIAL CATALYTIC ACTIVITY OF AT LEAST ABOUT 0.25 BASED UPON A STARTING FEED COMPOSITION OF 35 WEIGHT PERCENT ACRYLONITRILE AND 65 WEIGHT PERCENT WATER, TOTAL COMPOSITION BASIS, USING AN ARITHMETIC MEANS CATALYST BED TEMPERATURE OF 210*F., A CATALYST BED VOLMUNE OF ABOUT 50 CUBIC INCHES AND AN EVALUATION WEIGHT HOURLY SPACED VELOCITY WHICH IS SUFFICIENT TO PRODUCE 80 PERCENT CONVERSION OF ACRYLONITRILE TO ACRYLAMIDE, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF A. REMOVING FROM SERVICE ONE OF SAID THREE TUBULAR REACTION ZONES, AND B. PASSING SAID REACTANT COMPOSITION SEQUENTIALLY, SUBSTANTIALLY IOSTHERMALLY, AND UNDER LIQUID PHASE CONDITIONS THROUGH REMAINING TWO OF SAID THREE TUBULAR REACTION ZONES AT A SYSTEM WEIGHT HOURLY SPACE VELOCITY IN THE RANGE FROM ABOUT 0.5 TO 10 HOURS-1 WHILE MAINTAINING THE FIRST SAID REMAINING TWO REACTION ZONES AT A TEMPERATURE RANGE FROM ABOUT 100* TO 250*F, AND THE SECOND OF SAID REMAINING TWO REACTION ZONES AT A TEMPERATURE RANGING FROM ABOUT 120* TO 300*F.,THE CONVERSION OF STARTING ACRYLONITRILE TO ACRYLAMIDE AFTER PASSING THROUGH THE FIRST OF SAID REMAINING TWO REACTION ZONES BEING FROM ABOUT 15 TO 55 PERCENT, AND BEING FROM ABOUT 35 TO 99 PERCENT AFTER PASSING THROUGH THE SECOND OF SAID REMAINING TWO REACTION ZONES.

Claim 37

IN AN IMPROVED PROCESS FOR HYDROLYZING WITH A FIXED BED CATALYST ACRYLONITRILE TO ACRYLAMIDE OF THE TYPE EMPLOYING THREE TUBULAR REACTION ZONES THROUGH WHICH IN NORMAL PROCESS OPERATION A REACTANT COMPOSITION COMPRISING FROM ABOUT 25 TO 75 WEIGHT PERCENT ACRYLONITRILE AND FROM ABOUT 25 TO 75 WEIGHT PERCENT WATER ON A 100 WEIGHT PERCENT TOTAL COMPOSITION BASIS IS PASSED SEQUENTIALLY, SUBSTANTIALLY, ISOTHERMALLY, AND UNDER LIQUID PHASE CONDITIONS, EACH OF SAID REACTION ZONES CONTAINING A BED OF RANEY COPPER CATALYST WHICH HAS AN INITIAL CATALYTIC ACTIVITY OF AT LEAST ABOUT 0.25 BASED UPON A STARTING FEED COMPOSITION OF 35 WEIGHT PERCENT ACRYLONITRILE AND 65 WEIGHT PERCENT WATER, TOTAL COMPOSITION BASIS, USING AN ARITHMETIC MEANS CATALYST BED TEMPERATURE OF 210*F., A CATALYST BED VOLMUNE OF ABOUT 50 CUBIC INCHES AND AN EVALUATION WEIGHT HOURLY SPACED VELOCITY WHICH IS SUFFICIENT TO PRODUCE 80 PERCENT CONVERSION OF ACRYLONITRILE TO ACRYLAMIDE, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF A. REMOVING FROM SERVICE ONE OF SAID THREE TUBULAR REACTION ZONES, AND B. PASSING SAID REACTANT COMPOSITION SEQUENTIALLY, SUBSTANTIALLY IOSTHERMALLY, AND UNDER LIQUID PHASE CONDITIONS THROUGH REMAINING TWO OF SAID THREE TUBULAR REACTION ZONES AT A SYSTEM WEIGHT HOURLY SPACE VELOCITY IN THE RANGE FROM ABOUT 0.5 TO 10 HOURS-1 WHILE MAINTAINING THE FIRST SAID REMAINING TWO REACTION ZONES AT A TEMPERATURE RANGE FROM ABOUT 100* TO 250*F, AND THE SECOND OF SAID REMAINING TWO REACTION ZONES AT A TEMPERATURE RANGING FROM ABOUT 120* TO 300*F.,THE CONVERSION OF STARTING ACRYLONITRILE TO ACRYLAMIDE AFTER PASSING THROUGH THE FIRST OF SAID REMAINING TWO REACTION ZONES BEING FROM ABOUT 15 TO 55 PERCENT, AND BEING FROM ABOUT 35 TO 99 PERCENT AFTER PASSING THROUGH THE SECOND OF SAID REMAINING TWO REACTION ZONES.