Table 1.

Vapor Phase Chlorination of 2-Thiophenecarbonitrile 20: Product Composition as a Function of Reactor Temperature (GC Area % Values)

Temp (°C)	630	600	550	500
Dichloro isomers	< 5%	6.3%	5.3%	1.7%
22	1.1%	1%	1%	<0.5%
3	84.9%	83.7%	89.0%	90.5%
21	5.7%	3.4%	1.6%	0.6%
HCE a	1.0%	3.5%	4.0%	7.8%
Yield 3 b	73%	69%	81%	93%

^aHexachloroethane

^bBased on a GC assay method using 3,4,5,6-tetrachloro- 2-pyridinenitrile as internal standard.