Hammick, Dalziel Llewellyn (1887–1966)

English chemist whose major contributions were in the fields of theoretical and synthetic organic chemistry. He devised a rule to predict the order of substitution in benzene derivatives.

Hammick was born in London and studied at Oxford and Munich, Germany. In 1921, he returned to Oxford as a lecturer.

Hammick initially researchied inorganic substances, particularly with regard to their solubilities. He studied sulphur and its compounds (such as carbon disulphide), and suggested structures for liquid sulphur and plastic sulphur (which later workers interpreted in terms of linear polymers).

In 1922, he showed that the sublimation of α-trioxymethylene results in the polymer polyoxymethylene; 40 years later this substance was to be used as a commercial polymer.

Hammick spent much time investigating organic reaction rates. He studied, for example, the decarboxylation of quinaldinic acid (the alpha-, ortho- or 2-carboxylic acid of quinoline) by aldehydes and ketones. The reaction, now known as the Hammick reaction, is used in the synthesis of larger molecules.