Esters in the context of "Dephosphorylation"

An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one- or two-step mechanism. The one-step mechanism is known as the E2 reaction, and the two-step mechanism is known as the E1 reaction. The numbers refer not to the number of steps in the mechanism, but rather to the kinetics of the reaction: E2 is bimolecular (second-order) while E1 is unimolecular (first-order). In cases where the molecule is able to stabilize an anion but possesses a poor leaving group, a third type of reaction, E1_CB, exists. Finally, the pyrolysis of xanthate and acetate esters proceed through an "internal" elimination mechanism, the E_i mechanism.

Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula C₂O2−4. This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na₂C₂O₄), and several esters such as dimethyl oxalate ((CH₃)₂C₂O₄). It is a conjugate base of oxalic acid. At neutral pH in aqueous solution, oxalic acid converts completely to oxalate.

Transesterification is the process of exchanging the organic functional group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. Strong acids catalyze the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile. Bases catalyze the reaction by removing a proton from the alcohol, thus making it more nucleophilic. The reaction can also be accomplished with the help of enzymes, particularly lipases (one example is the lipase E.C.3.1.1.3).

If the alcohol produced by the reaction can be separated from the reactants by distillation this will drive the equilibrium toward the products. This means that esters with larger alkoxy groups can be made from methyl or ethyl esters in high purity by heating the mixture of ester, acid/base, and large alcohol.

A pear drop is a British boiled sweet made from sugar and flavourings. "Old-fashioned" pear drops are a combination of half pink and half yellow in a pear-shaped drop about the size of a thumbnail, although they are more commonly found in packets containing separate yellow drops and pink drops in roughly equal proportions ("original"). The artificial flavours isoamyl acetate and ethyl acetate are responsible for the characteristic flavour of pear drops: the former confers a banana flavour, the latter a pear flavour. Both esters are used in many pear- and banana-flavoured sweets. However, a natural pear-derived product from pear juice concentrate is sometimes used.

The largest pear drop in the world is housed at Stockley's Sweets in Oswaldtwistle Mills in Oswaldtwistle, Lancashire, England. In 2009 a survey of 4,000 adults found that pear drops were the fourteenth most popular sweet in the United Kingdom.