Search results
Results From The WOW.Com Content Network
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).
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 ...
Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline.
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.
For example, the substituent may determine the mechanism to be an SN1 type reaction over a SN2 type reaction, in which case the resulting Hammett plot will indicate a rate acceleration due to an EDG, thus elucidating the mechanism of the reaction. Another deviation from the regular Hammett equation is explained by the charge of nucleophile.
Alkylbenzenes are derivatives of benzene, in which one or more hydrogen atoms are replaced by alkyl groups. The simplest member, toluene (or methylbenzene), has the hydrogen atom of the benzene ring replaced by a methyl group. The chemical formula of alkylbenzenes is C n H 2n-6. [2] Safety hazards of toluene.
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.