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Abstract
Lanonol phosphate was synthesized by a sustained-release phosphorylation reaction method using P^sub 2^O^sub 5^ dispersed in lanonol phosphate. The phosphorylation reaction studies confirmed the best condition was a reaction temperature of 75 °C, a reaction time of 2.5 h and a molar ratio of hydroxyl and P^sub 2^O^sub 5^ of 3.0:1.0. The mole fraction of monoalkyl phosphate made by the sustained-release method increased by 14.3% compared to that obtained by the direct addition of P^sub 2^O^sub 5^. Preparation of lanonol phosphates by this method overcomes the agglomeration problem of phosphorus pentoxide, and the reaction rate is steady. Since lanonol phosphate was used as the dispersant for P^sub 2^O^sub 5^ powder, impurities due to the presence of other dispersants were eliminated, allowing synthesis of a nearly pure product. A mixture of monoalkyl phosphate and dialkyl phosphate with high monoalkyl content is obtained with light color. It is an eco-friendly reaction with minimal waste.
Keywords Lanolol phosphate * Dispersant * Sustained-release phosphorylation * Phosphate esters
Introduction
Phosphate esters are an important category of surfactant. They exhibit many excellent properties such as low toxicity, remarkable biodegradation, antistatic behavior, emulsification and dispersing power, and wetting properties [1]. They are widely used in the chemical, textile, leather, plastic, cosmetics and papermaking industries. Phosphates are prepared by the phosphorylation reaction of an organic compound containing a hydroxyl group and phosphorylating reagents such as phosphoric acid. Phosphoric acid is a ternary acid, so phosphate monoester, diester and triester products form, but the monoesters and diesters are most common. The water solubility, emulsification properties and antistatic behavior of monoesters are typically better than those of the diesters [2]. The application areas of monoester are very wide, so increasing the fraction of monoester in phosphate ester products has been a major research focus in the last few years [3]. O'Lenick and O'Lenick [4] invented novel multifunctional phospholipid surfactants. The products are very good wetting agents, have improved hydrolytic stability, are extremely substantive to human skin and are well tolerated by human tissue making them suitable for use in barrier products for personal care applications.
The common phosphorylating reagents are P^sub 2^O^sub 5^, POCl^sub 3^, PCl^sub 3^ and pyrophosphate. When P^sub 2^O^sub 5^ is used as the phosphorylating reagent, the reaction condition is...