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Formyl functional group is shown in blue. Formylation refers to any chemical processes in which a compound is functionalized with a formyl group (-CH=O). In organic chemistry, the term is most commonly used with regards to aromatic compounds (for example the conversion of benzene to benzaldehyde in the Gattermann–Koch reaction).
However, another effect that plays a role is the +M effect which adds electron density back into the benzene ring (thus having the opposite effect of the -I effect but by a different mechanism). This is called the mesomeric effect (hence +M) and the result for fluorine is that the +M effect approximately cancels out the -I effect.
Methylation, in the chemical sciences, is the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These terms are commonly used in chemistry, biochemistry, soil science, and biology.
The reaction is used for the transfer of methyl and ethyl groups between benzene rings. This is of particular value in the petrochemical industry [1] to manufacture p-xylene, styrene, [2] and other aromatic compounds. Motivation for using transalkylation reactions is based on a difference in production and demand for benzene, toluene, and xylenes.
Deactivated substrates give better results under modified chloromethylation conditions using chloromethyl methyl ether (MOMCl) in the presence of 60% H 2 SO 4. [ 4 ] Highly activated arenes like phenols and anilines are not suitable substrates, since they undergo further electrophilic attack by Friedel-Crafts alkylation with the formed benzylic ...
The equation also holds for reaction rates k of a series of reactions with substituted benzene derivatives: log k k 0 = σ ρ {\displaystyle \log {\frac {k}{k_{0}}}=\sigma \rho } In this equation k 0 {\displaystyle {k}_{0}} is the reference reaction rate of the unsubstituted reactant, and k that of a substituted reactant.
Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor. Typically aromatization is achieved by dehydrogenation of existing cyclic compounds, illustrated by the conversion of cyclohexane into benzene.
Mesitylene or 1,3,5-trimethylbenzene is a derivative of benzene with three methyl substituents positioned symmetrically around the ring. The other two isomeric trimethylbenzenes are 1,2,4-trimethylbenzene (pseudocumene) and 1,2,3-trimethylbenzene (hemimellitene).