p-Toluenesulfonic acid (PTSA) is an organic compound with the formula CH3C6H4SO3H. An aromatic sulfonic acid, often used as a strong acid catalyst. p-Toluenesulfonic acid monohydrate has been used as a reducing agent for the reductive amination of ketones and aldehydes. In the presence of p-Toluenesulfonic acid monohydrate novel deazaflavin-cholestane hybrid compounds have been synthesized in a condensation reaction. 2-Phenylethyl alpha-glucoside has also been synthesized in the presence of p-Toluenesulfonic acid monohydrate. p-toluenesulfonic acid esters, are a common class of reagents used in the pharmaceutical industry as alkylating agents, catalysts, and in purification steps of the chemical synthesis of a drug substance.

Ethylenediamine is a strongly basic amine useful as a building block in chemical synthesis. It is used as a solvent to dissolve proteins such as albumins, casein and in medicine to stabilize aminophylline when used in injections. Ethylenediamine is used in manufacture of chelating agents (EDTA), epoxy curing agents, dimethylolethylene-urea resins, emulsifying agents, textile lubricants, antifreeze inhibitor. It is also involved in the manufacture of many industrial chemicals and forms derivatives with carboxylic acids, nitriles, alcohols, alkylating agents, carbon disulfide, aldehydes and ketones. It is a basic building block to prepare heterocyclic compound such as imidazolidines.