Monsanto Company

Chen-Hsyong Yang

Chung Y Shen

Gary J Lynch

David O Fisher

James L Champion

There is disclosed an improved process for the semi-continuous production of phosphorus trichloride by the reaction of elemental phosphorus and chlorine in a liquid phosphorus trichloride layer. In accordance with the present invention periodic termination of the process by discontinuing phosphorus feed thereby creating a heel containing residual phosphorus is rendered more safe and less waste is produced by the improvement which comprises chlorinating the residual phosphorus at a substantially constant flow rate and continuing the chlorine feed rate until after observing at least one of either a step-wise decrease in the pressure within the reactor or a step-wise decrease in the flow rate of phosphorus trichloride removed from the reactor and then terminating the chlorine feed when said pressure and flow rate achieve a substantially steady state at a lower value.

Semi-continuous process for preparing phosphorus trichloride

There is disclosed a process for the controlled hydrolysis of phosphorus trichloride which avoids the formation of lower oxides of phosphorus, phophines and diphosphines wherein phosphorus pentachloride is added to the phosphorus trichloride from about 20 to about 90 percent by weight of the phosphorus trichloride and then water in the form of finely divided droplets is added over the surface of the phosphorus trichloride while the temperature is controlled to below about 80.degree. C.

Hydrolysis of phosphorus trichloride

The disclosed process is employed to recover phenol from aqueous solutions produced by distillation of the product of a process for producing a phenyl ester by the reaction of a carboxylic acid and phenol. Purified phenyl ester is employed to extract phenol from the aqueous solution. The extract is combined with raw product for recovery of the phenol and phenyl ester. In a preferred embodiment the process for producing the phenyl ester is continuous and the extract containing phenol and phenyl ester are fed to the dewatered ester stream for product recovery.

Growing community of inventors

Chesterfield, MO, United States of America

Chen-Hsyong Yang