transolefinen

Transolefinen are a class of alkenes in which the substituents on the carbon–carbon double bond are on opposite sides. They represent the trans (or E) isomer of a given olefin, in contrast to the cis (Z) arrangement where substituents lie on the same side. The term transolefin is often used in traditional literature, while modern naming uses the E/Z system to describe stereochemistry.

Configuration and naming: For simple disubstituted alkenes, trans corresponds to the E configuration when the higher-priority groups on each double-bond carbon are on opposite sides. The Z configuration corresponds to cis. In more complex cases, the CIP rules determine the exact E or Z designation.

Production and synthesis: Transolefinen can be prepared by stereoselective reactions that favor E products, such as certain Wittig or Horner–Wade reactions with appropriate reagents, as well as by selective hydrogenation of alkynes under conditions that promote trans addition. They can also arise or be enriched by isomerization of existing cis isomers under suitable catalytic conditions or thermal treatment.

Properties: Transolefinen are typically more linear and experience reduced steric hindrance between substituents across the double bond, which contributes to greater thermodynamic stability relative to the corresponding cis isomers. These geometric differences influence physical properties such as melting and boiling behavior and can affect polarity and reactivity.

Applications: They are used as intermediates in organic synthesis, in the preparation of specialty chemicals, and as monomeric building blocks in certain polymers and materials. The trans geometry can impact packing, rigidity, and material properties in such applications.

Safety: Standard chemical safety practices apply; consult substance-specific safety data sheets for handling, storage, and disposal. See also cis–trans isomerism and stereochemistry.