Method for improving thermal stability of dibutyl/diisobutyl phthalate

Abstract

The invention provides a method for r improving thermal stability of dibutyl / diisobutyl phthalate, and belongs to the technical fields of fine organic synthesis and application and machine shaping of macromolecular new materials. The method which improves the intrinsic thermal stability of plasticizers of dibutyl phthalate and diisobutyl phthalate by an inorganic carbonate heat treatment is characterized in that: protonic acid, such as sulfuric acid, is adopted to serve as an esterifying catalyst, coarse ester is thermally decomposed by anhydrous solid carbonates in a reaction system prepared through esterifying synthesis of benzoic anhydrides and n-butyl alcohol or isobutyl alcohol, the catalyst and byproducts generated in the reaction process are effectively removed, coloring byproducts in the esterifying reaction system can be effectively removed, the effect of improving the product stability is achieved, and the requirement on thermal treatment of polyvinyl chloride (PVC) products is met; compared with the conventional production methods, the method has the advantages that: process wastewater is reduced by two-thirds, the production period is shortened, and the aims of energy conservation and emission reduction are fulfilled.

Description

technical field [0001] The invention relates to a method capable of improving the internal thermal stability of dibutyl phthalate and diisobutyl phthalate products, and belongs to the technical fields of fine organic synthesis, application and processing of new polymer materials. Background technique [0002] Ortho-phthalate plasticizers are the world's largest production and most widely used plastic processing aids, dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) are important plasticizer products One of them has been used as the main plasticizer of PVC for a long time. It can effectively increase the plasticity and softness of polymer materials, and can effectively improve the mechanical properties of products. It is widely used in various PVC products, such as o-phthalic Di(2-ethyl)hexyl phthalate (DEHP), dibutyl phthalate (DBP) and butyl bisbian phthalate (BBP), diisononyl phthalate (DINP), Compounds such as diisodecyl phthalate (DIDP) and di-n-octyl phthalate (...

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Problems solved by technology

[0002] Ortho-phthalate plasticizers are the world's largest production and most widely used plastic processing aids, dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) are important plasticizer products One of them has been used as the main plasticizer of PVC for a long time. It can effectively increase the plasticity and softness of polymer materials, and can effectively improve the mechanical properties of products. It is widely used in various PVC products, such as o-phthalic Di(2-ethyl)hexyl phthalate (DEHP), dibutyl phthalate (DBP) and butyl bisbian phthalate (BBP), diisononyl phthalate (DINP), Compounds such as diisodecyl phthalate (DIDP) and di-n-octyl phthalate (DNOP), but currently industrially produced dibutyl phthalate (DBP) and diisobutyl phthalate ( DIBP) also use protonic acid sulfuric acid as a catalyst for esterification, and non-esterification catalysts have not been used in the production of dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP). It is the low activity of the existing non-sulfuric acid low-temperature catalyst to catalyze the reaction between phthalic anhydride and alcohols below C4, which leads to a long production cycle of the reaction, expensive catalyst, and increased industrial production costs; the production cost of the protonic acid sulfuric acid catalyst is low. It has higher catalytic esterification reaction activity at lower temperature, especially after catalyzing the reaction of phthalic anhydride and C4 alcohol for about 5 hours, the conversion rate of phthalic anhydride can reach about 99%, and the reaction efficiency is high, but its disadvantage is that the selectivity of the reaction is poor, which will cause Some unnecessary side reactions occur, resulting in poor thermal stability of the ester product. During the heating process, the structure of the product decomposes to produce colored organic compounds due to the existence of its by-products, which significantly increases the acid value and color of the product after heating. In addition, The current production technology route also needs to use a large amount of alkaline water for neutralization and multiple washing processes, resulting in a large amount of alkali-containing process wastewater discharge, with a COD value of about 8000-12000, which has become a technical difficulty for domestic and foreign industrial production of such ester products.

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