Abstract: A process for the preparation of gamma-cyahlothrin comprising a) chlorinating 1R cis-Z 3-(2-chloro-3,3,3-triflu-oro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid to give 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cy-clopropanecarboxylic acid chloride; b) esterifying 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylic acid chloride with 3-phenoxy benzaldehyde in the presence of a source of cyanide to form a diastereoisomeric mixture of cyhalothrin isomers and c) epimerising the diastereoisomeric mixture under conditions in which the least soluble diastereoisomer crystallises from solution.

Abstract: A method to start a combined unit gas turbine and electrical unit having a static start drive including the steps of: applying a variable frequency voltage from the static start drive to a winding of the generator to accelerate the combined unit to a turbine self-sustaining speed; accelerating the combined unit beyond the self-sustaining speed by applying torque generated by the turbine, and as the combined unit accelerates to a synchronous speed, applying a braking torque from the static start drive to steady the combined unit at the synchronous speed.