Piperylene

1,3-pentadiene is an imprecise term for two chemical compounds from the group of the dienes each other isomer ( geometric isomers ) is. It is also referred to as piperylene ( as the derivative of piperine ).

Production and representation

1,3-pentadiene can be prepared by methylation of 1,3- butadiene with dimethylsulfoxide in the presence of a base such as potassium tert -butoxide, obtained with a mixture of about 80% trans-and 20% cis -1 ,3- pentadiene obtained.

The preparation can also be carried out by a Wittig reaction from acetaldehyde, acrolein or crotonaldehyde, with both the yield and the cis / trans selectivity in function of various factors (such as the starting material or the solvent used ) varies.

There is also produced during the Hofmann elimination of piperidine, which is converted by repeated exhaustive methylation and subsequent elimination of trimethylamine in 1,4- pentadiene, but the isomerized under the reaction conditions to give the 1,3 -pentadiene.

It is also formed as a by- product of the separation process of the raw materials of pyrolysis gasoline C5 ( pygas ) - both byproducts of the production of ethylene.

Properties

1,3-pentadiene is a colorless liquid.

Use

1,3-pentadiene can be used for the preparation of other chemical compounds such as 2- methylfuran. It is also used as a monomer in the production of plastics, adhesives and resins. Piperylene -based products are particularly in modern adhesives - and used worldwide in road markings - such as in the manufacture of envelopes, package tapes and diaper fasteners.