from JACS vol 74 pg840, 1952
Synthesis of Nitriles in Ethylene Glycol(1)
Low-boiling nitriles cannot be made from alkyl halides and sodium cyanine in aqueous alcohol because of the difficulty of isolating the products from the solvent. However, other solvents which dissolve appreciable amourlts of sodium cyanide can be used. Thus, ethylene glycol has been used in the preparation of 5-hexenonitrile from 5-bromo-1-pentene(2), and its monoalkyl ethers, as well as tetrahydrofurfuryl alcohol, have been used in the preparation of succinonitrile and adiponitrile.
There are relatively few examples in the literature of the formation of secondary cyanides by displacement reactions, and none at all of tertiary cyanides. Low yields in these reactions are commonly attributed to olefin formation(4), but there have been no quantitative studies to bear this out.
Several of the solvents tried were found to be quite unsatisfactory. n-Butyl bromide was largely unchanged after a 40-hour reflux with sodium cyanide in n-butyl cellosolve or nitrobenzene. t-Butyl chloride in t-butyl alcohol gave a high yield of isobutylene.
i-Butyl bromide in hydrogen cyanide gave a little olefin along with unidentifiable material, although the sodium cyanide dissolved in the hydrogen cyanide to the extent of 0.54 g. per 100 cc. t-Butyl bromide in cold saturated aqueous sodium cyanide gave only a black tar.
Ethylene glycol proved to be a much more suitable solvent, even though it is not miscible with the alkyl halides. Table I shows the results of experiments with several primary, secondary and tertiary halides. In all runs there is some loss in the form of undistillable black residues. Other than this, the main side-reaction is the formation of glycol monoalkyl ethers (solvolysis), olefins are a relatively minor product.
The reactions with the primary halides were particularly gratifying. Valeronitrile, for instance, was prepared in 90% yield after one hour of reflux, and was readily separated from the reaction mixture by distillation. The best yield reported in aqueous alcohol after 25-30 hours of reflux and a careful, 10-hour distillation is 80%(5). Butyronitrile has been made in aqueous alcohol, but not isolated.(6)
TABLE I
REACTION OF ALKYL HALIDES WITH SODIUM CYANIDE
Initial Reaction
Alkyl temp., time Yield, %
halide C. hr. Nitrile Ether Olefin
n-BuBr 101 1 90
n-PrBr 72 1 92
i-PrBr 60 24 39
i-PrBr(a) 60 15 39 16 7
s-BuBr(a) 92 4 28 Low
s-BuCl 68 22 No reaction
t-BuBr(a) 73 3(b) Low 44
t-BuC1 50 6 Low 41
t-BuC1(a) 46 6 10(c) 27 18
(a)Sulfuric acid added. (b)Reaction seemed to be complete
in one hour. (c)Impurities may reduce this to about 5%.
-table II(identification of products) omited(just b.p´s of the above compounds) -
Although the yields of secondary cyanides are only fair, the fact that they can be easily obtained in a single step may make the reaction useful. Isobutyronitrile, for instance, cannot be made in aqueous alcohol, and is difficult to make by indirect methods. It is doubtful whether this method of preparing t-butyl cyanide (pivalonitrile) is practical.
In a few runs part of the excess sodium cyanide was neutralized with sulfuric acid in an attempt to reduce the over-all alkalinity. This reduced the proportion of glycol ether in the product; the effect was small, however, and it was concluded that the alkoxide ion, HOCH2CH2O-, which might have been present in the unbuffered solution, was
not directly responsible for ether formation.
Experimental
The alkyl halides and ethylene glycol were redistilled before use. The sodium cyanide was Baker Analyzed, 98% minimum.
The general procedure was to mix 150 cc. of ethylene glycol, 0.5 mole of the alkyl halide and 0.55 mole of sodium cyanide in a 500cc. three-necked flask, and to heat under reflux with constant stirring until the end of the reaction.
The initial temperature, measured by a thermometer in the vapor, was always close to the boiling point af the halide, and the end of the reaction was marked by a rapid rise in
termperature to a constant value as the last of the halide was used up. In a few runs 0.1 mole of sulfuric acid and an additional 0.2 mole of sodium cyanide were added before heating. In the reaction with n-butyl bromide it was observed that the heat of reaction was sufficient to maintain spontaneous reflux at the start.
The liquid products were distilled from the reaction mixture through a three-ball Snyder column. Where further purification of the nitriles was required they were washed with 4 N hydrochloric acid, 10% sodium bicarbonate and water, dried and redistilled through a 9inch or 18-inch packed column. Their properties are listed in Table II. The odor revealed that traces of isocyanide were still present in all cases.
In the runs in which olefin was determined the evolved gases were passed through soda-lime to remove hydrogen cyanide, and condensed in a trap at -80C. The olefins were then converted to the dibromides by passing them into a sodium tribromide solution, prepared from 70 g. of sodium bromide, 112 g. of bromine and 300 cc. of water. The dibromides were washed with sodium carbonate and sodium thiosulfate solutions, dried and weighed.
(1) From the M. S. thesis of Peter V. Susi, September, 1951
(2) F. B. LaForge, N. Green and W. A. Gersdorff, THIS JOURNAL, 70, 3707 (1948).
(3) A. O. Rogets, USPatent 2,416,261, Feb 4 1917
(4) D.T. Morey, Chem. revs. 42, 189 (1948)
(5) R. Adams and C.S. Marvel, THIS JOURNAL, 42,310(1920)
(6) K.W. Rosenmund, K. Luxat and W. Tiedemann, Ber. 56,1950 (1923)
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Well shit, where do you get your acetamide and phosphorus pentoxide/boric oxide from, anyway? The grocery? And how the fuck would I know what you can or cannot get? If you have access to MeOH and H2SO4, with good equipment you can make DMS. And there are numerous ways posted here to make NaCN out of more OTC materials. This shouldn´t be more work than making acetamide and fucking Boric oxide, wich would require very high temperatures to make, and I´ll just leave P2O5 alone.
I don´t want to start a discussion but I´m upset because I took the time to translate that procedure and edit this article to text format just to get flamed. I´m sympathetic with you on the aquisition problem, as I myself can´t get neither NaCN nor DMS, nor can I get acetonitrile. I just wanted to provide another way to solve it than the ones discussed.
And another interesting thing in this article is their procedure for making the dibromides of the olefin byproducts. They use 0.68 mol NaBr to 0.75 mol Br2 in 300ml of water. Maybe the dibromide of isosafrole(or any other propenyl benzene) can be made with in situ generation of Br2. This is a new thing for me, I alway thought that, with water present, the bromohydrin would be formed instead. But this discussion is better left to another thread.