brain drain. brain drain. LINK / CITE ADD TO WORD LIST. noun. The definition of brain drain refers to a situation where all or the majority of intelligent, skilled or capable resources within a given field or geographic region leave the area because of various factors including lack of high paying jobs.
Alkylation is an important source for octane in gasoline. Source: Occupational Safety and Health Administration. Alkylation (al-kuh-ley-shun) is a secondary refinery unit operation that many refineries in the United States have because it adds high octane hydrocarbons to motor and aviation gasoline. High octane hydrocarbons are needed to help prevent autoignition of gasoline (knocking) in an engine and to meet recommended engine octane ratings.
1 In general, an aldol condensation is the attack of a nucleophile on a carbonyl to make a Î²-hydroxy ketone or aldehyde. Usually the nucleophile is an enolate of an aldehyde or ketone that attacks another molecule of the aldehyde or ketone. The aldol condensation can be catalyzed by either an acidic or basic solution.f the difference in the pK a s is large enough, pH can be used to deprotonate just one of the esters. 2 Crossed Claisen reactions are very important in biological processes. The first step of the citric acid cycle is an enzyme catalyzed condensation of acetyl-CoA, a thioester, with oxaloacetate.