废物作为要求的转化中的催化剂:可扩展性视角

Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.

The Fischer esterification reaction was developed by the German chemist Emil Fischer in 1895. It is a condensation reaction between carboxylic acids and alcohols in an acidic medium to give esters and water.

Hydrolysis of esters under acidic conditions proceeds through a nucleophilic acyl substitution. In the presence of excess water, the reaction proceeds in a reversible manner, forming carboxylic acids and alcohols.
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...

Regular Claisen condensation involves the synthesis of β-ketoesters by combining identical ester molecules bearing two α hydrogens in the presence of an alkoxide base. The reaction commences with the deprotonation of the acidic α hydrogen by the base to form a resonance stabilized ester enolate. This nucleophilic ion then attacks the carbonyl center of another ester molecule to generate a tetrahedral alkoxide intermediate. Next, the expulsion of the alkoxide group from the...

Carboxylic acids react with alcohols to yield esters via an acid-catalyzed condensation reaction called Fischer esterification. This is a nucleophilic acyl substitution reaction that proceeds via a tetrahedral intermediate, where a water molecule is eliminated as the leaving group.

Esters can be hydrolyzed to carboxylic acids under acidic or basic conditions. Base-promoted hydrolysis of esters is a nucleophilic acyl substitution reaction in which esters react with an aqueous base, followed by an acid to give carboxylic acids. This reaction is also known as saponification because it forms the basis for making soaps from fats.
The reaction requires a base in stoichiometric amounts, which participates in the reaction and is not regenerated later. So, the base acts as a...