Patent ID: 7541484

Claim:
A process for producing a phosphate, which comprises the step of reacting a phosphorus pentaoxide-containing phosphorylating agent with an organic hydroxy compound to produce a phosphate, the reaction being carried out at a reaction temperature of 50 to 70° C. until the degree (W) of remaining phosphorus pentaoxide undissolved in a reaction solution, defined by the following equation (1), is reduced to 10 wt % or less: W=[ 1−( AV t −AV p )/ AV 0 ]×100 (1) wherein W is the degree [wt %] of remaining phosphorus pentaoxide undissolved in a reaction solution; AV t is the acid value [mg KOH/g] of the reaction solution excluding undissolved phosphorus pentaoxide in an arbitrary time; AV p is the theoretical acid value [mg KOH/g] of the phosphorylating agent excluding undissolved phosphorus pentaoxide; and AV 0 is the theoretical acid value [mg KOH/g] of phosphorus pentaoxide.