Methods for the preparation of alkenes including insect pheromones are described. The methods include homologation reactions employing reagents such as 1,3-diesters, epoxides, cyanoacetates, and cyanide salts for elongation of starting materials and intermediates by one or two carbon atoms. The alkenes include insect pheromones useful in a number of agricultural applications.

An ethylene glycol composition, a preparation method thereof, and a polyester prepared from the ethylene glycol composition are provided. The ethylene glycol composition of the present invention has a specific content of propylene glycol, butanediol and hexanediol. The polyester obtained by polymerizing the ethylene glycol composition with a dibasic acid such as terephthalic acid has a low glass transition temperature and excellent toughness while maintaining excellent strength and heat resistance, which can greatly broaden the application scope of the polyester, and is particularly useful for low-temperature dyeing fibers.

An ethylene glycol composition, a preparation method thereof, and a polyester prepared from the ethylene glycol composition are provided. The ethylene glycol composition of the present invention has a specific content of propylene glycol, butanediol and hexanediol. The polyester obtained by polymerizing the ethylene glycol composition with a dibasic acid such as terephthalic acid has a low glass transition temperature and excellent toughness while maintaining excellent strength and heat resistance, which can greatly broaden the application scope of the polyester, and is particularly useful for low-temperature dyeing fibers.