Alkylation of aromatic amines

Claim 2

A process for alkylating aromatic amines comprising the step of reacting (a) an aromatic amine having at least one replaceable hydrogen atom on a primary amino group and on an aromatic ring carrying such amino group, with (b) a dialkyl ether in which each alkyl group has 2 to 4 carbon atoms, in the presence of a metal oxide alkylation catalyst consisting essentially of titanium dioxide having a surface area below 130 square meters per gram and at a temperature in the range of 300° C. to 400° C. at which alkylation of the aromatic amine occurs and at which the amount of exclusively ring-alkylated product formed exceeds the amount of exclusively N-alkylated product formed.

Claim 3

A process of claim 1 wherein the ether is diethyl ether.

Claim 4

A process of claim 1 wherein the amine is a mononuclear primary aromatic amine having one or two amino groups on the aromatic ring.

Claim 5

A process of claim 3 wherein the amine is aniline, one or a mixture of two or more toluidine isomers or one or a mixture of two or ore xylidine isomers.

Claim 6

A process of claim 4 wherein the ether is diethyl ether.

Claim 7

A process of claim 1 wherein the reaction is conducted in the vapor phase by contacting a vapor phase mixture of the amine and the ether with a bed of the catalyst.

Claim 8

A process of claim 1 wherein the reaction is conducted at a temperature of at least about 325° C. but below that at which the catalyst becomes inactive.

Claim 9

A process of claim 1 wherein the catalyst is composed predominantly or entirely of titanium dioxide in the anatase crystallographic form.

Claim 10

A process for alkylating aromatic amines comprising the step of reacting (a) an aromatic amine having at least one primary amino group on an aromatic ring and having a replaceable hydrogen atom on the ring in at least an ortho or para position relative to such amino group, with (b) a dialkyl ether in which each alkyl group has 2 to 4 carbon atoms, in the presence of a metal oxide alkylation catalyst consisting essentially of titanium dioxide having a surface area below 130 square meters per gram and at a temperature in the range of 300° C. to 400° C. at which alkylation of the aromatic amine occurs and at which the amount of exclusively ring-alkylated product formed exceeds the amount of exclusively N-alkylated product formed.

Claim 11

A process for alkylating aromatic amines comprising the step of reacting (a) an aromatic amine having at least one primary amino group on an aromatic ring and having a replaceable hydrogen atom on the ring in at least an ortho or para position relative to such amino group, with (b) a dialkyl ether in which each alkyl group has 2 to 4 carbon atoms, in the presence of a metal oxide alkylation catalyst consisting essentially of titanium dioxide having a surface area below 130 square meters per gram and at a temperature in the range of 300° C. to 400° C. at which alkylation of the aromatic amine occurs and at which the amount of exclusively ring-alkylated product formed exceeds the amount of exclusively N-alkylated product formed.

Claim 12

A process of claim 9 wherein the ether is diethyl ether.

Claim 13

A process of claim 9 wherein the reaction is conducted in the vapor phase by contacting a vapor phase mixture of the amine and the ether with a bed of the catalyst at a temperature of at least about 325° C. but below that at which the catalyst becomes inactive.

Claim 14

A process of claim 11 wherein the amine is aniline, one or a mixture of two or more toluidine isomers or one or a mixture of two or more xylidine isomers, and the ether is diethyl ether, dipropyl ether or dibutyl ether.

Claim 15

A process of claim 11 wherein the catalyst is composed predominantly or entirely of titanium dioxide in the anatase crystallographic form.

Claim 16

A process of alkylating aromatic amines comprising the step of reacting (a) an aromatic amine having at least one replaceable hydrogen atom on a primary amino group and on an aromatic ring carrying such amino group, with (b) a dialkyl ether in which each alkyl group has 2 to 4 carbon atoms, in the presence of a metal oxide alkylation catalyst consisting essentially of titanium dioxide having a surface area of about 112 square meters per gram and at a temperature in the range of about 325° to about 400° C. so that alkylation of the aromatic amine occurs and so that the amount of exclusively ring-alkylated product formed exceeds the amount of exclusively N-alkylated product formed.

Claim 17

A process of alkylating aromatic amines comprising the step of reacting (a) an aromatic amine having at least one replaceable hydrogen atom on a primary amino group and on an aromatic ring carrying such amino group, with (b) a dialkyl ether in which each alkyl group has 2 to 4 carbon atoms, in the presence of a metal oxide alkylation catalyst consisting essentially of titanium dioxide having a surface area of about 112 square meters per gram and at a temperature in the range of about 325° to about 400° C. so that alkylation of the aromatic amine occurs and so that the amount of exclusively ring-alkylated product formed exceeds the amount of exclusively N-alkylated product formed.

Claim 18

The process of claim 14 wherein the temperature is in the range of about 350° to about 400° C.