US2101750A

US2101750A - Manufacture of monomethyl-paraaminophenol and its sulphate

Info

Publication number: US2101750A
Application number: US76696A
Authority: US
Inventors: Norman Simon
Original assignee: Industrial Dyestuff Co
Current assignee: Industrial Dyestuff Co
Priority date: 1935-07-30
Filing date: 1936-04-27
Publication date: 1937-12-07
Anticipated expiration: 1954-12-07

Description

. sulphate, and more particularly to improvements Patented Dec. 7, 1937 UNITED STATES PATENT oFFice MANUFACTURE OF MONOMETHYL-PARA- AMINOPHENOL AND ITS SULPHATE Simon Norman, Providence, E. I., assignor to Industrial Dyestuff Company, East Providence, R. 1., a corporation of Rhcde Island No Drawing. Original application July 30, 1935,

Serial No. 33,915. Divided and this application April 2'7, 1936, Serial No. 76,696

16 Claims.

The instant case is a division of my earlier application, Serial Number 33,915, filed July 30, 1935.

This invention relates to improvements in the manufacture of N-methyl-para-aminophenol 201The proportions of these media employed are generally from ten to twelve times the Weight of the glycine.

It has been extremely dii'ficult to find media which are not required in such large amounts in order to complete the decomposition ofthe glycine in a reasonable time andwhich do not resinify when heatedfor long periods in contact with methylated aminophenoLflespecially when used in large scale production in the factory.

-It has also been diflicult to prevent decomposition of N-methyl-para-aminophenol formed during the heat treatment. Decomposition of the N-methyl-para-aminophenol and resinification seriously affect the yield of the finished N-methyl- -para-aminophenol sulphate, as well as the recovery of the media.

An object ofv the present invention is, therefore, to provide a process in which the aforesaid difliculties, particularly that of preventing resinification and that of preventing decomposition of the final product, are overcome.

Another object is to provide a highly efficient process in which para-hydroxy-phenylglycine is decomposed under controlled conditions in a medium of such nature as to cause a rupture of the glycine grouping at a relatively low temperature and bring about the completion of the reaction in a relatively short time.

A further object is to provide a relatively inexpensive process by which to carry on the above reaction, and which process permits of practically complete recovery of the final product and of the media in which the reaction is carried out.

The media which are employed in the present process have been found to be even more satisfactory than the products of the hydrogenation of phenols, cresols, and their homologs, and they consist of a whole series of aliphatic ketones, or a mixture thereof.

I have found that any aliphatic ketone, preferably those containing one methyl or ethyl group attached to the 0:0 linkage and boiling at C., or over, or mixtures of the same, having a resultant boiling range above 145 C., will decompose para-hydroxy-phenylglycine satisfactorily and give the resultant compound, monomethylparaaminophenol.

It has been found that the reactions herein disclosed require much lesser amounts to effect the decomposition than any of the compounds mentioned in the prior art, and still allow a very small amount of by-products and impurities to form.

The following examples serve to illustrate the present invention:

Example 1.-Into'a suitable apparatus, charge 1 part, by weight of para-hydroxy-phenylglycine, 5 parts, by weight, of methyl-butylketone, and 5 parts, by weight, of methyl-hexylketone. The

mass is stirred and heated to attain a temperature'of from 140 C. to C. The temperature is now maintained at this point for a period of about 20 minutes, after which time conversion occurs. The resulting product is now cooled externally to about 25 C., whereupon it is diluted by the addition of about 100 parts, by Weight, of ethyl alcohol and the whole well mixed. The diluted mass is now treated with the stoichiometric amount of concentrated sulphuric acid, which causes the sulphate of N-monomethyl-paraaminophenol to separate from the solution. After stirring the mass for a suitable period of time, it is filtered 011 and washed with alcohol until the mother liquor has been removed. The N-mono-methyl-para-aminophenol sulphate is obtained in excellent yield and high purity.

Example 2.--1 part, by weight, of para-hydroXy-phenylglycine is mixed with 5 parts, by weight, of methyl-propylketone, and 5 parts, by weight, of methyl-n-nonylketone. The temperature of the mixture is brought to 150 C. to C., and it is converted in about 20 minutes. The process is then finished by treating the mass as above. It will be noted, in this example, that a mixture of a low boiling ketone and a high boiling'ketone, to give a boiling range of from 150 C. to 160 C., gave a satisfactory result. Consequently, where the boiling point of the pure aliphatic ketone is below 145 C., the addition of enough higher boiling ketone will give a remethyl-para-aminophenol sultant boiling point in the decomposition temperature range, and still give a satisfactory result.

What I claim is:

1. A process of manufacturing monomethylpara-aminophenol, which process comprises decomposing parahydroxy-phenylglycine to monoin reaction media containing essentially a mixture of straight chain aliphatic ketones having a resultant boiling point of at least 145 C.

2. A process as set forth in claim 1, wherein the mixture of ketones includes methyl-n-butylketone.

3. A process as set forth in claim 1, wherein the mixture of ketones includes methyl-n-hexylketone.

4. A process as set forth in claim 1, wherein the mixture of ketones includes essentially methyl-n-propylketone.

5. A process as set forth in claim 1, wherein the mixture of ketones includes methyl-n-nonylketone.

6. A process of manufacturing monomethylpara-aminophenol, which process comprises decomposing para-hydroxy-phenylglycine to monomethyl-para-aminophenol in media containing essentially metiiyl-n-butylketone and methyl-nhexylketone.

7. In the process set forth in claim 6, the steps which consist in mixing 1 part, by weight, of para-hydroxy-phenylglycine, 5 parts, by weight, of methyl-n-butylketone, 5 parts, by weight, of methyl-n-hexylketone, heating the mixture to a temperature of 140 C. to 150 0., for a period of about 20 minutes, diluting the resulting mass with alcohol, and adding sufficient sulphuric acid to convert the monomethyl-para-arninophenol base into monomethyl-para-aminophenol sulphate.

8. A process of manufacturing monomethylpara-aminophenol, which comprises decomposing para-hydroxy-phenylglycine to monomethylpara-aminophenol in media containing essentially methyl-propylketone and methyl-n-nonylketone.

9. In the process set forth in claim 8, the steps which consist in mixing 1 part, by Weight, of para-hydroxy-phenylglycirie, 5 parts, by Weight, of methyl-propylketone, 5 parts, by weight, of methyl-n-nonylketone, heating the mixture to a temperature of 150 C. to 160 C., for a period of about 20 minutes, diluting the resulting mass with alcohol, and adding sufficient sulphuric acid to convert the monomethyl-para-aminophenol base into monomethyl-para-aminophenol sulphate.

10. A process of manufacturing monomethylpara-aminophenol, which process comprises decomposing para-hydroxy-phenylglycine to monomethyl-para-aminophenol in reaction media containing essentially a straight chain aliphatic ketone having a low boiling point and a straight chain aliphatic ketone having a higher boiling point, whereby the resultant boiling point of the reaction mixture will be above 145 C.

11. A process of the character described, comprising decomposing para-hydroxy-phenylglycine to monomethyl-para-aminophenol in reaction media, having a resultant boiling point of 'at least 145 C. and containing essentially a mixture of straight chain aliphatic ketones, and stirring the reaction mixture with a solution containing an amount of sulphuric acid suflicient to convert the monomethyl-para-aminophenol base into vmonomethyl-para-aminophenol sulphate.

12. A process of the character described, comprising decomposing para-hydroxy-phenylglycine to monomethyl-para-aminophenol in reaction media having a resultant boiling point of at least 145 C. and containing essentially a mixture of straight chain aliphatic ketones, diluting the resulting mass with alcohol, and adding sufficient sulphuric acid to convert the monomethyl-paraaminophenol. into monomethyl-para-aminophenol sulphate.

13. In the process set forth in claim 12, the additional steps of stirring the resulting mass for a period of about twenty minutes, filtering off and then washing off with alcohol until the mother liquor has been removed.

14. A process of manufacturing monomethylpara-aminophenol, which process comprises decomposing para-hydroxy-phenylglycine to monomethyl-para-aminophenol by means of heat in protecting media comprising essentially a mixture of straight chain aliphatic ketones and having a resultant boiling point of at least 145 C.

15. A process of manufacturing monomethylpara-aminophenol, which process comprises decomposing para-hydroxy-phenylglycine to monomethyl-para-aminophenol in reaction media containing essentially a mixture of non-cyclic aliphatic ketones having a resultant boiling point of at least 145 C.

16. A process of manufacturing monomethylpara-aminophenol, which process comprises decomposing para hydroxy-phenylglycine to monomethyl-para-aminophenol in reaction media containing essentially a mixture of non-cyclic aliphatic ketones having a resultant boiling point of about 145 C.

SIMON NORMAN.