Dioctyl terephthalate plasticizer and method of enhancing reaction efficiency in process for producing the same

A method for use in enhancing reaction efficiency for producing a terephthalate plasticizer, comprising steps of:

• (1) mixing a purified terephthalic acid (PTA) and a C6-C10 alcohol in a weight ratio of 1:0.8-1.5 and processed in a homogenizer for 2-8 hours so as to form a PTA slurry having a PTA particle size between 80 and 110 μm and a specific surface area at least 0.3723 m2/g, wherein increase rate of the specific surface area is between 5 and 10%;
• (2) providing 75-107 wt % of the PTA slurry of Step (1) and 30-85 wt % of the C6-C10 alcohol, both based on a total weight of the terephthalate plasticizer of Step (5);
• (3) providing 0.1-2.0 wt % of a titanium-based catalyst as an esterification catalyst, based on the total weight of the terephthalate plasticizer of Step (5);
• (4) esterifying the components of Step (2) with the presence of the esterification catalyst of Step (3) at a pressure of between −30 and 1013 mbar and a temperature of between 200 and 250° C. for 2-3 hours to form a reaction mixture;
• (5) after esterification, neutralizing the reaction mixture with an aqueous solution of alkaline metal hydroxide that contains a 5-20 wt % of hydroxide mixture, until the reaction mixture having its acid value reduced to below 0.07 mgKOH/g, and then removing the residual C6-C10 alcohol, drying and filtration, so as to obtain the terephthalate plasticizer;
• wherein the C6-C10 alcohol is selected from 2-ethylhexanol (2-EH), isononyl alcohol (INA), and isodecyl alcohol.