Study On Synthesis And Application Of Hexamethylene Plasticizers

Hexamethylene plasticizers are a new kind of environment-friendly nonbenzenoid plasticizers. They are available for the plasticizers which are direct contact with skin instead of phthalate. Synthesizing techniques of di-nonyl 1,2-cyclohexanedicarboxylate (DNCH), di-butyl 1,2-cyclohexanedicarboxylate (DBCH), poly diglycol 1,2-cyclohexanedicarboxylate(PDCH) were studied.The one-factor experiment results showed that the optimized reaction conditions of synthesizing DNCH were determined as follows: n(n-nonyl alocohol)︰ n(hexahydrophthalic anhydride) = 2.8︰1, amount of sulfamic acid was 0.20%( based on the mass of reactant), reaction temperature was190℃, reaction time was 5 h, esterification yield was up to 99.0%. The product was refined by dealcholization, neutralization, bathing and evaporation. LD50 of DNCH was greater than 10000 mg/kg, actually nonpoisonous. The color, acid value, aspect of DNCH were past muster. Resistance transference and resistance abstraction of DNCH was tested.The one-factor experiment results showed that the optimized reaction conditions of synthesizing DBCH were determined as follows: n(butyl alcohol)︰n(hexahydrophthalic anhydride) = 3︰1, amount of catalyst was 0.60%(based on the mass of reactant), m(Ce(SO₄)₂·4H₂O)︰m(NH₂SO₃H)=2︰1, reaction temperature was135℃, reaction time was 9 h, esterification yield was up to 99.0%. After refining the product by dealcholization, neutralization, bathing and evaporation, the purity of DBCH was 99.06%. LD50 of DBCH was greater than 10000 mg/kg, actually nonpoisonous. The color, acid value, aspect of DBCH were all past muster.The one-factor experiment results showed that the optimized reaction conditions of synthesizing PDCH catalyzed by etrabutyl titanate were determined as follows: n(diethylene glycol)︰n(hexahydrophthalic anhydride) = 1.1︰1, amount of etrabutyl titanate was 0.47%( based on the mass of reactant), esterification temperature was 220℃, esterification time was 5 h, under a pressure of -0.095 MPa, condensation time was 2.5 h, condensation temperature was 220℃, esterification yield was up to 99.0%. The product was brown. Number-average molecular weight of PDCH was 14000 g/mol, and weight-average molecular weight of PDCH was 15000 g/mol. The product had a narrow molecular weight distribution index which was 1.07. Viscosity of PDCH was 2300 Pa·S(25℃). Acid value was 0.97mgKOH/g. Heating loss was 0.0039. Density was 1.30g/mL. The dosage of end capping reagent had no effect on molecular weight and viscosity.The one-factor experiment results showed that the optimized reaction conditions of synthesizing PDCH catalyzed by methanesulfonic acid were determined as follows: n(diethylene glycol)︰ n(hexahydrophthalic anhydride) = 1.1︰ 1, amount of methanesulfonic acid was 0.40%(based on the mass of reactant), esterification temperature was 220℃, esterification time was 5 h, under a pressure of -0.095 MPa, condensation time was 2 h, condensation temperature was 160℃, esterification yield was up to 99.0%. The product was light brown. Number-average molecular weight of PDCH was 13000 g/mol, and weight-average molecular weight of PDCH was 14000 g/mol. The product had a narrow molecular weight distribution index which was 1.08. Viscosity of PDCH was 2200 Pa·S(25℃). Acid value was 1.85 mgKOH/g. Heating loss was 0.0031. Density was 1.27 g/mL.It can be inferred from the comparison above that both catalysts for PDCH have advantages and disadvantages. End point acid value of the reaction catalyzed by etrabutyl titanate could below 1 mgKOH/g. But the color of product was darker. Viscosity and molecular weight were higher. Condensation time was longer. Condensation temperature was higher. End point acid value of the reaction catalyzed by etrabutyl titanate was 1.85 mgKOH/g, higher. But the color of product was lighter. Viscosity and molecular weight were lower. Condensation time was shorter. Condensation temperature was lower.