Acetonitrile from pyrolysis

Terpolymer samples (0.6-0.7 mg) were pyrolysed at 550 °C and 600 °C. The major products of pyrolysis were found to be ethylene, propylene, butadiene, benzene, toluene, and vinyl cyclohexene from the butadiene part, and acrylonitrile and acetonitrile from the acrylonitrile part of the polymers. 

Acetonitrile oxide was generated from 3,4-dimethylfuroxan oxide by flash vacuum pyrolysis and trapped at -40 °C where its and NMR spectra were examined. Warming to room temperature in the presence of propane produced 3,5-dimethyl-2-isoxazoline (Scheme 108) (79TL2443). The oxide could also be generated by photolysis of furoxan (68CC977). 

CH4, and H2 while minor products such as HCCCN, H2C=CHCN, C2H4 and C4H2 were also detected. Ab initio chemical calculations revealed that the pyrolysis of acetonitrile is initiated by CH bond fission, forming a cyanomethyl radical. Products such as HCCN and H2C=CHCN have been shown to arise from the decomposition of succinonitrile, that forms by the recombination of two cyanomethyl radicals. The kinetics of thermocyclization of 2,3-diethynylquinoxaline (109) (Bergman cyclization) have been studied in various solvents. Non-polar solvents give shorter half-lives and better yields. The cyclization rates observed were found to be solvent dependent. ... 

Photolysis and p5Tolysis of 4-phenyltriazole gives mainly phenyl-acetonitrile pyrolysis of 4,5-diphenyltriazole in solution gives 2,3,5,6-tetraphenylpyrazine, which is formally derived from the triazole by loss of nitrogen, dimerization, and oxidation (Scheme 58). ... 

Figure 8. Pyrolysis gas chromatographs of size fractions A) 0.45-0.1 micrometers and B) 3K-1K molecular weight of samples obtained from Saganashkee Slough. Marker compounds and retention times are 1) acetonitrile, 5.97 min 2) thiophene, 6.10 min, and toluene, 6.33 min 3) anisole, 11.90 min 4) acetic acid, 13.82 min 5) pyrolle, 15.64 min 6) acetamide, 20.34 min 7) phenol and o-cresol, 25,18 min 8) m-cresol and p-cresol, 26.67 min and 9) indole, 32.53 min.

There is considerably more information about nitriles from natural gas or petroleum this is to be expected since there are two distinct routes to these substances—from hydrogen cyanide and a hydrocarbon (CeHe + HCN - C H5CN -H H2) and from the pyrolysis of ammonia and hydrocarbons, particularly low-carbon number hydrocarbons, as in CHj + NH3 + CftHe - CeHfcCN 4- 4H2. The latter process is reviewed by Groggins (7), and is extended to imsaturated hydrocarbons. Both acetonitrile and acrylonitrile are so obtained industrially. 

FIGURE 10.15 Pyrolysis of a feather from a wild turkey at 650"C. Peaks 1 = sulfur dioxide, 2 = acetonitrile, 3 = propanenitiile, 4 = toluene. 

Matter, P.H., Wang, E., Aries, M, Biddinger, E.J., and Ozkan, U.S. (2006) Oxygen reduction reaction catalysts prepared from acetonitrile pyrolysis over alumina-supported metal particles. J. Phys. Chem. B, 110, 18374-18384. 

---