초록 ▼

This invention provides a process for purifying the crude aromatic dicarboxylic acids produced by oxidation of dialkyl aromatic hydrocarbons and for using the purified acids in the preparation of polyethylene terephthalate, polyethylene naphthalate and other polyesters. The invention simplifies the

This invention provides a process for purifying the crude aromatic dicarboxylic acids produced by oxidation of dialkyl aromatic hydrocarbons and for using the purified acids in the preparation of polyethylene terephthalate, polyethylene naphthalate and other polyesters. The invention simplifies the manufacturing process by converting the crude aromatic acids into bis-glycol esters in an esterification reactor 4, from which the esterified partial oxidation impurities present in the oxidation product are removed by distillation in distillation tower 5. After removal of the volatile impurities, the dicarboxylic acid esters can separated by distillation in distillation tower 6 or by crystallization and converted to polyesters by polycondensation. The volatile impurities removed as overhead from tower 5 can be recycled as stream 16 to the oxidation reactor where they act as oxidation promoters thereby optionally allowing for a bromine-free oxidation process for dialkyl aromatic hydrocarbons.

대표청구항 ▼

This invention provides a process for purifying the crude aromatic dicarboxylic acids produced by oxidation of dialkyl aromatic hydrocarbons and for using the purified acids in the preparation of polyethylene terephthalate, polyethylene naphthalate and other polyesters. The invention simplifies the

This invention provides a process for purifying the crude aromatic dicarboxylic acids produced by oxidation of dialkyl aromatic hydrocarbons and for using the purified acids in the preparation of polyethylene terephthalate, polyethylene naphthalate and other polyesters. The invention simplifies the manufacturing process by converting the crude aromatic acids into bis-glycol esters in an esterification reactor 4, from which the esterified partial oxidation impurities present in the oxidation product are removed by distillation in distillation tower 5. After removal of the volatile impurities, the dicarboxylic acid esters can separated by distillation in distillation tower 6 or by crystallization and converted to polyesters by polycondensation. The volatile impurities removed as overhead from tower 5 can be recycled as stream 16 to the oxidation reactor where they act as oxidation promoters thereby optionally allowing for a bromine-free oxidation process for dialkyl aromatic hydrocarbons. P>and R2are independently selected from the group consisting of hydrogen and lower alkyl groups of from about 1 to 5 carbon atoms; R3is R1R5wherein R5is any branched or straight chain perfluoroalkyl of from about 1 to 25 carbon atoms; R4is R1R6wherein R6is any branched or straight chain perfluoroalkyl of from about 5 to 25 carbon atoms; R is selected form the group consisting of linear and branched alkyl groups; and X is a hydrolyzable group or atom, comprising: (a) reacting an alkyldialkoxysilane with a perfluoroalkyl-substituted silane to produce a perfluoroalkyl-substituted dialkylsiloxyalkylsilane intermediate; (b) reacting the intermediate with halogen. 9. The process according to claim 8, for producing the compound of formula II, comprising: (a) reacting methyldiethoxysilane with tridecafluorodimethylchlorosilane to produce a bis(tridecafluorooctyldimethylsiloxy)methylsilane intermediate; (b) reacting the intermediate with halogen.