Process for making acrylamide

Claim 2

A CONTINUOUS PROCESS FOR CATALYTICALLY HYDROLYZING ACRYLONITRILE TO CRYLAMIDE COMPRISING THE STEPS OF A. CONTINUOUSLY MOVING WATER UNDER LIQUID PHASE CONDITIONS THROUGH AT LEAST ONE ELONGATED SUBSTANTIALLY PLUG FLOW REACTION ZONE, B. ADDING TO THE LIQUID IN SAID ZONE OR ZONES AT NO LESS THAN TWO LOCATIONS ALONG SAID ZONE OR ZONES ACRYLONITRILE, THERE BEING AT LEAST ONE SUCH ADDITION LOCATION IMMEDIATELY BEFORE OR WITHIN EACH OF SAID ZONES IF MORE THAN ONE ZONE IS PRESENT, THE RATE OF SUCH ADDITION BEING SUCH THAT THE TOTAL WEIGHT PERCENT OF WATER IN SAID LIQUID IN SAID ZONE OR ZONES DECLINES FROM A MAXIMUM TO A MINIMUM BETWEEN THE FIRST AND THE LAST OF SUCH LOCATIONS AFTER MIXING, THE CALCULATED WEIGHT RATIO OF TOTAL ACRYLONITRILE CHARGED TO TOTAL WATER CHARGED RANGING FROM ABOUT 1:3 TO 3:1, 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 65 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% CONVERSION OF ACRYLONITRILE TO ACRYLAMIDE, SAID PROCESS A'' BEING CONDUCTED SUBSTANTIALLY ISOTHERMALLY AT INDIVIDUAL REACTION ZONE TEMPERATURES EACH BEING IN THE RANGE OF FROM ABOUT 100* TO 300*F., B'' HAVING A SYSTEM WEIGHT HOURLY SPACE VELOCITY IN THE RANGE OF FROM ABOUT 0.1 TO 10 HOURS -1.

Claim 3

The process of claim 1 wherein there are three of said reaction zones and wherein the quantity of acrylonitrile so added at each location ranges from about 0.5 to 1.5 times the total quantity of acrylonitrile charged to all such locations divided by the total number of such locations,

Claim 4

The process of claim 1 wherein there are four of said reaction zones and wherein the quantity of acrylonitrile so added at each location ranges from about 0.5 to 1.5 times the total quantity of acrylonitrile charged to all such locations divided by the total number of such locations,

Claim 5

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 6

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 7

The process of claim 1 wherein said catalyst is a copper-containing catalyst.

Claim 8

The process of claim 6 wherein said catalyst is a Raney copper catalyst.

Claim 9

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

Claim 10

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

Claim 11

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

Claim 12

The process of claim 1 wherein said zone 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 13

The process of claim 2 wherein said total system conversion is at least about 70%.

Claim 14

A continuous process for catalytically hydrolyzing acrylonitrile to acrylamide under substantially liquid phase conditions comprising continuously and sequentially moving water through least two tubular reaction zones, charging at least once to each such zone and the liquid therein acrylonitrile, the quantity of acrylon so charged to each such zone ranging from about 0.5 to 1.5 times the total quantity of acrylonitrile charged to all such zones divided by the total number of locations at which acrylonitrile is charged, the calculated wieght ratio of total acrylonitrile charged to total water charged ranging from about 1:3 to 3:1, 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 65 wt. % water, total composition basis, using an arithmetic mean catalyst bed temperature of 210*F., a catalys bed volume of about 50 cubic inches and an evaluation weight hourly space velocity which is sufficient to produce 80% conversion of acrylonitrile to acrylamide, said process (a'') being conducted substantially isothermally at individual reaction zone temperatures each being in the range of from about 100* to 300 *F, b'' having a system weight hourly space velocity in the range of from about 0.1 to 10 hours 1.

Claim 15

A continuous process for catalytically hydrolyzing acrylonitrile to acrylamide under substantially liquid phase conditions comprising continuously and sequentially moving water through least two tubular reaction zones, charging at least once to each such zone and the liquid therein acrylonitrile, the quantity of acrylon so charged to each such zone ranging from about 0.5 to 1.5 times the total quantity of acrylonitrile charged to all such zones divided by the total number of locations at which acrylonitrile is charged, the calculated wieght ratio of total acrylonitrile charged to total water charged ranging from about 1:3 to 3:1, 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 65 wt. % water, total composition basis, using an arithmetic mean catalyst bed temperature of 210*F., a catalys bed volume of about 50 cubic inches and an evaluation weight hourly space velocity which is sufficient to produce 80% conversion of acrylonitrile to acrylamide, said process (a'') being conducted substantially isothermally at individual reaction zone temperatures each being in the range of from about 100* to 300 *F, b'' having a system weight hourly space velocity in the range of from about 0.1 to 10 hours 1.

Claim 16

The process of claim 13 wherein there are two of said reaction zones.

Claim 17

The process of claim 13 wherein there are three of said reaction zones.

Claim 18

The process of claim 13 wherein there are four of said reaction zones.

Claim 19

The process of claim 13 wherein said catalyst is in the form of particles ranging in size from about 0.01 to 0.49 inch.

Claim 20

The process of claim 13 wherein said catalyst is in the form of particles ranging in size from about 0.02 to 0.3 inch.

Claim 21

The process of claim 13 wherein said catalyst is a copper-containing catalyst.

Claim 22

THe process of claim 19 wherein said catalyst in a Raney copper catalyst.

Claim 23

The process of claim 13 wherein said catalyst has such an initial activity of from about 0.25 to 2.

Claim 24

The process of claim 13 wherein said catalyst has such an initial activity of from about 0.45 to 1.5.

Claim 25

The process of claim 13 wherein said system weight hourly space velocity ranges from about 0.5 to 2.

Claim 26

The process of claim 13 wherein said zone temperature 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 27

The process of claim 13 wherein said total system conversion is at least about 70%.

Claim 28

The process of claim 13 wherein the product liquid mixture is subjected to stripping to recover therefrom unreacted acrylonitrile.

Claim 29

The process of claim 26 wherein said recovered acrylonitrile is recycled back to at least one of said reaction zones.

Claim 30

The process of claim 26 wherein said recovered acrylonitrile is recycled back to the first of said reaction zones.

Claim 31

The process of claim 26 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 32

The process of claim 26 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 33

The process of claim 13 wherein said quantity of acrylonitrile so charged to each zone ranges from about 0.75 to 1.25 times the total acrylonitrile charged divided by the number of locations at which acrylonitrile is charged.

Claim 34

The process of claim 13 wherein the total system conversion of starting acrylonitrile to acrylamide is at least about 75%.

Claim 35

A process for hydrolyzing with a fixed bed catalyst acrylonitrile to acrylamide comprising continuously passing sequentially through three substantially isothermal tubular reaction zones under homogeneous liquid phase conditions at a system weight hourly space velocity ranging from about 0.1 to 10 hours 1 a reactant composition comprised of acrylonitrile and water, such reactant composition being achieved by feeding substantially all the water to such first zone and by feeding incrementally to each such zone from about 0.2 to 0.5 times the total quantity of acrylonitrile charged to all such zones, each of said zones containing a fixed 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 and 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% conversion of acrylonitrile to acrylamide, said zones being maintained at temperatures ranging from about 100* to 300*F, there being a cumulative conversion of acrylonitrile to acrylamide in each such zone in the range of from about 60 to 90% based on total added acrylonitrile in each such zone and all prior zones, said process resulting in a total system conversion of starting acrylonitrile to acrylamide of at least about 75%, same basis.

Claim 36

A process for hydrolyzing with a fixed bed catalyst acrylonitrile to acrylamide comprising continuously passing sequentially through three substantially isothermal tubular reaction zones under homogeneous liquid phase conditions at a system weight hourly space velocity ranging from about 0.1 to 10 hours 1 a reactant composition comprised of acrylonitrile and water, such reactant composition being achieved by feeding substantially all the water to such first zone and by feeding incrementally to each such zone from about 0.2 to 0.5 times the total quantity of acrylonitrile charged to all such zones, each of said zones containing a fixed 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 and 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% conversion of acrylonitrile to acrylamide, said zones being maintained at temperatures ranging from about 100* to 300*F, there being a cumulative conversion of acrylonitrile to acrylamide in each such zone in the range of from about 60 to 90% based on total added acrylonitrile in each such zone and all prior zones, said process resulting in a total system conversion of starting acrylonitrile to acrylamide of at least about 75%, same basis.

Claim 37

The process of claim 33 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 38

The prOcess of claim 34 wherein acrylonitrile so removed is recycled to said reactant composition, as fed to said first zone.

Claim 39

The process of claim 1 wherein there are two of said reaction zones and wherein the quantity of acrylonitrile so added at each location ranges from about 0.5 to 1.5 times the total quantity of acrylonitrile charged to all such locations divided by the total number of such locations.

Claim 40

The process of claim 13 wherein the calculated weight ratio of total acrylonitrile charged to total water charged ranges from about 0.4 to 0.7.

Claim 41

IN AN IMPROVED PROCESS FOR HYDROLYZING WITH A FIXED BED CATALYST ACRYLONITRILE TO ACRYLAMIDE OF THE TYPE EMPLOYING

Claim 42

IN AN IMPROVED PROCESS FOR HYDROLYZING WITH A FIXED BED CATALYST ACRYLONITRILE TO ACRYLAMIDE OF THE TYPE EMPLOYING

Claim 43

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 acrylonitrile and water is passed sequentially, substantially isothermally, and under liquid phase conditions, such reactant composition being achieved by feeding substantially all of the water to the first of such reaction zones and by feeding incrementally to each such zone from about 0.2 to 0.5 times the total quantity of acrylonitrile charged to all such zones, each of said zones containing a fixed 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 and 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% conversion of acrylonitrile to acrylamide, the improvement which comprises the steps of a. removing from service one of said three tubular reaction zones, b. passing such reactant composition sequentially, substantially isothermally, and under liquid phase conditions through the remainiNg two of said three tubular reaction zones at a system weight hourly space velocity in the range from about 0.5 to 2.0 hours 1 while maintaining the first of said remaining two reaction zones at a temperature ranging from about 150* to 260*F., the cumulative conversion of starting acrylonitrile to acrylomide after passing through both of said remaining two reaction zones being in the range from about 70 to 90% based on total added acrylonitrile in each such zone and all prior zones.

Claim 44

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 acrylonitrile and water is passed sequentially, substantially isothermally, and under liquid phase conditions, such reactant composition being achieved by feeding substantially all of the water to the first of such reaction zones and by feeding incrementally to each such zone from about 0.2 to 0.5 times the total quantity of acrylonitrile charged to all such zones, each of said zones containing a fixed 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 and 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% conversion of acrylonitrile to acrylamide, the improvement which comprises the steps of a. removing from service one of said three tubular reaction zones, b. passing such reactant composition sequentially, substantially isothermally, and under liquid phase conditions through the remainiNg two of said three tubular reaction zones at a system weight hourly space velocity in the range from about 0.5 to 2.0 hours 1 while maintaining the first of said remaining two reaction zones at a temperature ranging from about 150* to 260*F., the cumulative conversion of starting acrylonitrile to acrylomide after passing through both of said remaining two reaction zones being in the range from about 70 to 90% based on total added acrylonitrile in each such zone and all prior zones.