USRE22930E - Tertiary - Google Patents

Description

Reissued Oct. 21, 1947 UNITED STATES PATENT OFFICE TERTIARY BUTYL DERIVATIVE OF HEMI- PROGESSFQR FIQEPAB- Marion Scott Carpenter, Nutley, N. 1., assignor to Givaudanellelawanna, Ina, New York, N. Y., a corpora ion o New J y No Drawing. Original No. 2,144,615, dated January 24, 1939, Serial No. 55,847, December 23,

1935. Serial No. 756,797

This invention relates to a tertiary butyl derivative of. hem mellitene and to processes for its manufacture.

In my copending application,

Serial No.

' 756,798, filed June 24, 1947, for the reissue of U. S.

atoms with an aliphatic compound containing a;

carbon atoms in the presence of an acid condensing agent. The tort-butyl hemimellitene may thus be obtained:

(1) By introduction of a tort-butyl group into pseudocumene by the Friedel-Crafts reaction:

CH CH3 A101: CH

(2) By introduction of a methyl group into tert-butyl m-xylene by the method of Blane (chlor-methylation and subsequent dechlorination):

+ HCHO HQ] 04H GH:

CH; CH.

CHgCl CH;

211 NaOH 04110 CH3 C4 CH3 The following examples indicate various ways in which the foregoing new substances may be synthesized, it being understood that I do not limit myself to the precise conditions herein described.

Example 1 65 g. tort-butyl chloride is added, with constant agitation, to a suspension of 5 g. anhydrous aluminum or ferric chloride in 300 g. pseduocumene at a temperature of about 510 C. When the reaction has subsided, the mixture is washed with water until free of acid and inorganic salts. The excess pseudocumene is distilled off and the 4 Claims. (Cl. 260-668) Application for reissue June 24, 1947,

remaining tort-butyl hemimellitene distilled in vacuo, the fraction boiling at 92 C. under a vacuum of 3.5 min. being collected. By working at a higher temperature the iron or aluminum chloride may e replace y ti or t tan um tet achlori Example 2 To 1,380 g. sulfuric acid 93%, previously cooled to --10 0., there is added with efficient agitation a solution of 120 g. tert-butyl alcohol in 410 g. pseudocumene, maintaining the temperature between -10 and 0 C. The reaction mixture is poured onto ice and the oil which separates is washed free of acid and distilled as in Example 1.

Example 3 1750 g. 1,3-dimethyl-5-tert-butyl benzene, hereafter referred to as butyl xylene, 108 g. paraformaldehyde (or an equivalent quantity of commercial 37% formaldehyde solution) and 650 g. 31% hydrochloric acid are mixed and warmed to 50 G. Then with constant agitation there are added 1200 g. 82% sulfuric acid. After 5-6 hours agitation at 5'0-70" C. the formaldehyde is consumed and the reaction mixture is cooled. The acid layer is discarded, the oily layer is washed with water until free of acid and distilled, preferably in vacuo. The excess butyl xylene distills over first theri, under a vacuum of 4 mm. of mercury, there is collected the desired 2,6-dimethyl- 4-tert-butyl benzyl chloride boiling at 117-120 C. It soon congeals to colorless, massive rhombs melting at about 26-27 C. The specific gravity at 25 C. of the super-cooled liquid is about 1.0030-1.0040. For the dechlorination of the 2,6- dimethyl-4-tert-butyl benzyl chloride it is not necessary that it be distilled from the excess butyl xylene; the crude product obtained from the above reaction may be submitted directly to the dechlorination process, although I prefer to remove the butyl xylene first. 355 g. zinc dust are covered with 500 g. water and the suspension heated to G. Then, with vigorous agitation there are introduced simultaneously the 2,6-dimethyl-4-tert-butyl benzyl chloride produced in the first step (either distilled or in the crude form containing butyl xylene) and 855 g. 18% sodium hydroxide solution. Stirring and refluxing are continued until the oily layer is free of chlorine. The oil is driven over with steam (or separated by decantation from the zinc slime) and redistilled as in Example 1. Without departing from the spirit or scope of the invention numerous modifications of the above process may be used. For example, the proportions cited above may be varied within reasonable limits, the order of introduction of the reactants may be changed or all may be added at once, the time of reaction may by any of the above methods is a colorless, crystalline material soluble in the common organic solvents, boiling at 92 C. at 3.5 mm. of mercury pressure and melting at 32-33 C.

The invention claimed is:

1. 1,2,3-trimethyl-5-tert-butyl benzene, comprising a colorless crystalline material having a boiling point of 92 C. under 3.5 mm. of mercury and a melting point of 32-33 0.

2. Process of preparing a tert-butyl derivative of hemimellitene which comprises reacting butyl xylene, formaldehyde, hydrochloric acid and su1-' furic acid at 50-70" C., cooling the reaction mixture and discarding the acid layer, dechlorinatfuric acid at 50-70 0., cooling the reaction mixture and discarding the acid layer, treating the resulting 2,6-dimethy1-4-tert-butylbenzyl chlorideboiling at 1l'7-120 C. ina suspension of zinc dust, water and sodium hydroxide to remove chlorine, distilling off the oily layer, redistilling The tart-butyl hemimellitene Which is produced ,same and collecting the fraction boiling at 92 C. under 3.5 mm. ofmercury.

4. Process of preparing a tert-butyl derivative of hemimellitene which comprises mixing butyl xylene, formaldehyde and hydrochloric acid and warming to 50 C., adding sulfuric acid to said mixture and agitating for 5-6 hours at 50-70 C.,

ing the oily portion of the reaction mixture, discooling the reaction mixture and discarding the acid layer, collecting the 2,6-dimethyl-4-tertbutyl benzyl chloride boiling at 117-120" 0., introducing'same' with sodium hydroxide solution into a suspension of zinc dust and water heated to C., stirring and refluxing until the oily layer is free of chlorine, distilling off the oily layer, and

then redistilling and collecting the fraction boiling at 92 C.', under 3.5 mm. of mercury.

MARION SCOTT CARPENTER.

REFERENCES CITED The following references are of record in the file of this patent:

Fuson et al., J. A. C. S. 63, 2352-3 (1941).

Beil. V, 447.