US3641158A Current Assignee Evonik Corp  (1969) cresol/POCl3/Cl/hydrolysis (cresol process)

EXAMPLE 1 A mixture of 432 parts (4.00 moles) of o-cresol, 306 parts (2.00 moles) of phosphorus oxychloride, and 0.22 part of magnesium oxide was heated to 110 C. over a period of one hour and then from 110 C. to 180 C. over a period of three hours. It was maintained at 180 C. for three hours.
The reaction mixture was heated to 190-l95 C. and maintained at that temperature while chlorine was bubbled through it. The chlorination was continued until the weight increase indicated that P-chloro-di-(a,a-dich1oroo-cresyl) phosphate had been formed. When cooled to room temperature this ester was a mobile, clear, ambercolored oil.
Twenty-six hundred parts of water and 870 parts of P-chloro-di-(a,u-dichloro-o-cresyl) phosphate were placed in a flask that was equipped with an agitator, a Dean- Stark water trap, and a condenser. The reaction mixture 4 was heated to its boiling point (107 C.), and the steamdistillation of salicylaldehyde from the flask began at once. After about 3 hours the hydrolysis was complete, and 355 parts of crude salicylaldehyde had been collected. This crude salicylaldehyde was distilled through a fractionating column, and 300 parts of substantially pure 99.5%) salicylaldehyde was obtained.
Each of the other P-chloro-di-(a,u-dichloro-substituted cresyl) phosphates hereinbefore mentioned can be hydrolyzed in a similar way to the corresponding substituted salicylaldehyde, p-hydroxybenzaldehyde, or substituted p-hydroxybenzaldehyde.
The terms and expressions that have been used are used as terms of description and not of limitations. There is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof. It is recognized that various modifications are possible within the scope of the invention claimed. 

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US3314998A (1964)  Universal Oil Products Co

Example I Tri-(o-cresyl) phosphate was chlorinated until about he calculated amount of chlorine necessary to produce he alpha,alpha-dichlor derivative had been adsorbed. Vithout separation of any of the alpha,alpha-monochlor r -trichlor derivatives produced, this crude reaction prodlct was used directly in the hydrolysis. 1150 gms. of the rude chlorinated product were charged with about an :qual amount of water in a flask fitted with a stirrer and Bidwell type separator and condenser, and the mixture teated to reflux with vigorous stirring. salicylaldehyde tegan to distill slowly shortly thereafter and was collected [1 the Bidwell apparatus while the aqueous condensate vas continuously returned to the reaction mixture. After tbout two and one-half hours evolution of hydrogen chloide gas also commenced indicating that saturation of he aqueous phase with this material had occurred. The 'eaction was continued for about ten hours until both listillation of salicylaldehyde and evolution of hydrogen :hloride ceased. A total of 507.5 gms. of steam distilled .alicylaldehyde was collected, and upon fractional disillation of this material there were obtained 453 gms. :olorless salicylaldehyde analyzing 99.5% pure. 
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