Sciencemadness Discussion Board

benzylnitrile

contrived - 11-3-2007 at 22:33

I just read a post that indicated benzylnitrile might be made by distilling p-toluenesulfonic acid with NaCN. I haven't found any more on this. I would like to know but have limited access to academic reference library..

garage chemist - 11-3-2007 at 22:50

You probably mean benzonitrile, aka phenyl cyanide, C6H5CN.

Distilling p-toluenesulfonic acid with NaCN will get you the sodium salt of the acid and hydrogen cyanide gas.
In order for anything more interesting to occur you will have to use the sodium salt of the sulfonic acid.
And even if it worked, you would get para-tolunitrile. In order for benzonitrile to be obtained, you would have to use benzenesulfonic acid.

But if this actually yielded the aromatic nitrile it would be a very interesting reaction. In the "theoretical amphetamine variants" thread, Nicodem suggested that aromatic sulfonates and cyanides might not give the nitrile, although I had thought otherwise first. It would be good if reliable data could be found on this issue, especially as I have now seen in Ullmann that aromatic nitriles might actually be prepared from the sulfonates by fusion with cyanide.

This would make possible a conversion of the easily synthesized naphthalene-2-sulfonic acid into 2-naphthonitrile.

[Edited on 12-3-2007 by garage chemist]

Sauron - 12-3-2007 at 03:51

No telling what he means. Could be as you say (benzonitrile, nitrile directly on the ring) or could be benzyl cyanide (phenylacetonitrile) I suppose.

As neither would be produced by that reaction, and the nomenclature was somewhere between ambiguous and totally botched, the answer is up for grabs.

Which one did you have in mind, @contrived? -CN on the ring or -CN on the methyl? Inquiring minds want to know!

garage chemist - 12-3-2007 at 09:07

In my post, I was referring to the compound with the CN directly on the ring.
I have made and used both benzyl cyanide and benzonitrile, the former is very toxic and has an unpleasant smell, while the latter smells good (similar to benzaldehyde) and is of low toxicity.

You are right, the author of this thread did not say what compound he would like to make. "Benzyl nitrile" is not a chemical name.
But as the only compound that his proposed reaction may make is p-tolunitrile (if it works at all), I was talking about this one.

[Edited on 12-3-2007 by garage chemist]

Nicodem - 12-3-2007 at 11:17

Quote:
Originally posted by garage chemist
In the "theoretical amphetamine variants" thread, Nicodem suggested that aromatic sulfonates and cyanides might not give the nitrile, although I had thought otherwise first. It would be good if reliable data could be found on this issue, especially as I have now seen in Ullmann that aromatic nitriles might actually be prepared from the sulfonates by fusion with cyanide.

I was wrong in doubting the arylsulfonate salt to arylnitrile reaction as you proposed it. Instead of checking the literature first, I rather seeded doubts. Sorry about that. Now I finally checked it. Cyanides are not that oxidation sensitive as I thought and thus the reaction works. There are a dozen examples of such a transformation in the literature, mainly in the (very) old papers. I will try to correct my misleading by providing you the needed references:

Furthermore, even K4Fe(CN)6 can be used on sodium alpha- or beta-naphthalenesulfonate according to this paper:
Quote:
Derivatives of a- and b-naphthoic acids.
Wahl, Andre; Goedkoop, Martinus L.; Heberlein, Edouard.
Bull. Soc. Chim., 6 (1939) 533-548.

Abstract: A review and reinvestigation of methods for the prepn. of naphthoic acids (34 references) led to the selection of three: (1) C10H7MgBr + CO2 (Gilman, et al., C. A. 25, 2146), (2) sapon. of C10H7CN and (3) sapon. and oxidation of C10H7CH2Cl. The nitriles were best prepd. by strongly heating 400 g. of C10H7SO3Na and 300 g. of K4Fe(CN)6 with 100 g. of Fe2O3 and 100 g. of Fe turnings (to give better heat distribution). Although the yields were only 30 and 22% for the a- and b-nitriles, resp., this method is preferred to the Sandmeyer, which involves large vols. of soln. The nitriles were sapond. at 140° for 2 hrs. with 63 g. of NaOH and 460 cc. of EtOH per 100 g. a-C10H7CH2Cl (I) was best prepd. from C10H8, (CH2O)3, and HCl, following Darzens and Levy (C. A. 30, 2561.8). b-C10H7CH2Cl (II) was prepd. by passing dry Cl into b-C10H7Me and a little PCl3 at 230-50° until 60% of the theoretical Cl had reacted. I and II were changed to the corresponding aldehydes by hexamethylenetetramine (Mayer, et al., C. A. 17, 100) which were then oxidized to the corresponding acids by Na2Cr2O7 in boiling AcOH. See C. A. 32, 2930.3 for the conversion of the aldehydes into a- and b-C10H7COCH2CO2Et (III) and (IV), resp. In addn. to the derivs. described therein, the following are now reported: a-naphthylisoxazolone, m. 193° (by using NH2OH); oxime of a-C10H7Ac, m. 142° (by using NH2OH.HCl); a-C10H7COCH2CONHPh, m. 119-20°; a-C10H7COCH2CONHC6H4OMe-o, m. 124°; phenylazo deriv. of enolic III; p-nitrophenylazo deriv. of enolic III, m. 137°; and b-naphthylisoxazolone, m. 159°. This last gave b-naphthylisoxazoloneindoleindigo, b-C10H7C:N.O.CO.C:C.CO.C6H4.NH, deep red needles, m. 250°, b-naphthylisoxazole-2-(7-chloroindole)indigo, violet, m. 214-26°, and b-naphthylisoxazole-2-(5,7-dimethylindole)indigo, violet, m. 190-1°, when boiled in benzene with the appropriate isatin chloride. b-C10H7CHO gave 2,7-dimethyl-3,6-diamino-b-naphthylacridine, a brown basic dye, by condensation with m-tolylenediamine, cyclization, and oxidation.
When the pyrazolones of III and IV made with NH2NH2, PhNHNH2, and p-NO2C6H4NHNH2 were coupled in alk. soln. with diazotized sulfanilic and naphthionic acids, the resulting dyes gave very fast yellow shades on wool.

Warning: When using sulfonic acids without transforming them to sodium or potassium salts an equivalent of KCN is lost and HCN is evolved! I know this is obvious, but there are all kind of fools out there.

Sauron - 12-3-2007 at 12:34

@GC, my remarks and questions were not directed to you, but to @contrived. Nor were they intended to be particularly harsh. I have found his posts in general to be intelligent and thoughtful and so I was surprised to see him screw the pooch here.