US1272522A - Method of making benzaldehyde. - Google Patents

Description

came STATES caries.

Manna ru'rnm, or MID AND, MICHIGAN, assrenoa To run now cmrcan corarm, or maintain), mcmean,

A CORPORATION OF MICHIGAN.

' mnrnon or MAKING. n'anzannmnn. 1

No Drawing,

1 To all whom it may concern:

' a citizen of the United States, and a resi-' dent of Midland, county of Midland, and

a the chlorinated 'be readily oxidized 'to the al the use of ordinary Be it known that I, MARK E. PUTNAM,

State of Michigan, have invented a new and useful Improvement in Methods of Making Benzaldehyde, of which the following is a specification, the principle of the invention bein herein explained and the best mode in whic I have contemplated applying that principle, so as to distinguish 1t from other inventions.

The present improved process of making .benzaldehyde involves the use of benzyl bromid. I am aware that benz'aldehyde has heretofore been made using benzyl chlorid (see Ullmanns Enzg klopddde der Techm'ohen OIz-emz'e IL, 301) by treating the same with a solution of lead' nitrate. This method, however, has never proved of commercial importance for a variety of reasons, some ofwhich are referred to in the text named, benzal chlorid having proven a better starting point, and the process involved differing essentially from the one'just referred to,

I have found, however, that if instead of roduct of toluene, viz: the aforesaid benzyl chlorid, the bromid product, viz: benzyl bromid, is emplo ed, it may (lehyde not alone by the use of lead nitrate, for example, but much more readily andsatisfactoril by Chile saltpeter (so ium nitrate). The latter reagent will not react satisfactorily with the benzyl chlorid; but as just indicated, produces entirely satisfactory results with the bromid,-better in fact than can be secured by treating such chlorid with lead nitrate,,since the latter invariably results in theproduction of a certain amount of benzoic acid, which is undesirable in the connection in hand.

The present invention then consists of the steps hereinafter fully described and particularly pointed out in the claims, it being understood that the following description discloses only one of several ways in which the principle of the invention may be carried out. I

As. has already been indicated, the benzyl bromid (C,-,H,,.CH Br) whichis usedas a startin" point in the present procex' is roduced If I Specification of Letters Patent. Application filed September 18, 1916. Serial No. 120,590.

y brominating toluene (C a p the method by which such bromination is accomplished being no part of the present invention. The bromid is then mixed with a solution of sodium nitrate (NaNO ordinary Chile saltpeter, as stated, being satisfactory for the purpose; and the mixture thereupon raised approximately to the boiling pomt with constant stirring. The reaction which occurs may be represented by the following symbolic formula, viz: C H,,.CH Br-|-NaNO The resulting benzaldehyde (c,H,.oHo

being insoluble in water, ma ,be readily se arated from the solution 0 sodium bromid and nitrous acid, which are the other two products resulting from such reaction,

not in contradistinction to that obtained not only by the treatment of benzyl chlorid with lead nitrate, to which reference has hereinbefore been made, b t also to the other known processes which are commercially practised. y

In place of sodium nitrate, I have found that calcium nitratecan also be used to oxidize the bromid to the aldehyde with satisfactory results, but the sodium salt is preferred because, at present, it ismore readily obtainable and considerably less expensive than the other.

Other modes of applying the principle of .my invention may which consists in heating .a mixture 0 benzyl bromid and a nitrate without other rea ents being pr esent, substantially as descri ed.

i2. Themethod of benzaldehyde,-

which consists inheating a mixture of benzylbromid and the 'f'nitrate of an alkali metal or alkaline eartli without other reagents. being present,- substantially as described.

3. The method of making benzaldehyde,

Patented July re, 1918.

and is found to be practically a pure prodwhich consists in heating a mixture of stirring the mixture, substantially as debenzyl bromid and an alkali metal nitrate scribed. 10 without other reagents being present, sub- Signed by me, this 15th day of Sept. stantially as described. 1916.

5 A. The method of making ben'zaldehyde; I MARK E. PUTNAM.

which consists in mixing together benzyi Attested bybromid and Chile saltpeter without other re- A. N. PATRIARCHE,

agents being present, and then heating and JNo. F, @BERLIN.