Phosphorus oxychloride is an inorganic chemical compound with the formula POCl3. It is a colorless, fuming, highly reactive, and toxic liquid that is used as an intermediate in the production of a variety of chemicals, such as phosphates, phosphonates, and other phosphoryl compounds.
It is also used as a reagent in organic synthesis, particularly in the synthesis of esters and in the cross-linking of polymers. However, its handling should be done with caution as it can cause severe irritations and burns upon skin contact, and is toxic if ingested or inhaled.
In the esterification of starch
Phosphorus oxychloride can be used as a reagent in the esterification of starch to produce a modified starch product with cross-linked bonds. During the reaction, the phosphorus oxychloride reacts with the hydroxyl groups (-OH) on the starch molecule to form an ester bond, which creates a covalent bond between the starch molecules and forms a three-dimensional network. This network gives the modified starch improved stability and resistance to physical and chemical breakdown, compared to unmodified native starch. However, the use of phosphorus oxychloride can result in the production of potentially harmful byproducts, so it is important to carefully consider the safety and environmental impact of using this reagent in the esterification of starch.