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The effect of the tert-butyl group on the progress of a chemical reaction is called the Thorpe–Ingold effect illustrated in the Diels-Alder reaction below. Compared to a hydrogen substituent, the tert-butyl substituent accelerates the reaction rate by a factor of 240. [2] tert-Butyl effect. The tert-butyl effect is an example of steric hindrance.
Example: 2,2,3-trimethyl- . If there are both double bonds and triple bonds, "en" (double bond) is written before "yne" (triple bond). When the main functional group is a terminal functional group (a group which can exist only at the end of a chain, like formyl and carboxyl groups), there is no need to number it.
The Geneva Nomenclature of 1892 was created as a result of many other meetings in the past, the first of which was established in 1860 by August Kekulé. Another entity called the International Association of Chemical Societies (IACS) existed, and on 1911, gave vital propositions the new one should address: [ 2 ]
A cycloalkyl group is derived from a cycloalkane by removal of a hydrogen atom from a ring and has the general formula −C n H 2n−1. [2] Typically an alkyl is a part of a larger molecule. In structural formulae , the symbol R is used to designate a generic (unspecified) alkyl group.
Polymer nomenclature usually applies to idealized representations meaning minor structural irregularities are ignored. A polymer can be named in one of two ways. Source-based nomenclature can be used when the monomer can be identified. Alternatively, more explicit structure-based nomenclature can be used when the polymer structure is proven.
In chemical nomenclature, a descriptor is a notational prefix placed before the systematic substance name, which describes the configuration or the stereochemistry of the molecule. [1] Some of the listed descriptors should not be used in publications , as they no longer accurately correspond with the recommendations of the IUPAC .
Butyl acetate, an ester derived from a residue of butanol (CH 3 CH 2 CH 2 CH 2 OH) (the butanol residue is butyl group −CH 2 CH 2 CH 2 CH 3) (right side of the picture, blue) and acetic acid CH 3 CO 2 H (left side of the picture, orange). The acidic hydrogen atom (−H) from acetic acid molecule is replaced by the butyl group.
The repulsion between an axial t-butyl group and hydrogen atoms in the 1,3-diaxial position is so strong that the cyclohexane ring will revert to a twisted boat conformation. The strain in cyclic structures is usually characterized by deviations from ideal bond angles ( Baeyer strain ), ideal torsional angles ( Pitzer strain ) or transannular ...