Synthesis And Application Of Environment-friendly Plasticizer 2,2,4-trimethyl-1,3-pentanediol-diisobutyrate

In this work, 2,2,4-trimethyl-1,3-pentanediol-monoisobutyrate was first prepared via the Aldol condensation reaction and Tishchenko reaction using isobutyraldehyde as monomer and NaOH as a catalyst. Then TXIB(2,2,4-trimethyl-1,3-pentanediol-diisobutyrate) was synthesized via the esterification between the resultant 2,2,4-trimethyl-1,3-pentanediolmonoisobutyrate and isobutyric acid under the catalyst and water-carrying agent. Finally, the plasticization of TXIB was evaluated when applied in PVC and PVAc emulsion.2,2,4-Trimethyl-1,3-pentanediol-monoisobutyrate was prepared using isobutyraldehyde as monomer and NaOH as a catalyst. In Aldol condensation reaction, using NaOH ethanol aqueous solution(the weight ratio of ethanol to water is 3:1) as the catalyst system, the effect of some factors such as dosage of catalyst, reaction time and temperature on the yield of 2,2,4-Trimethyl-1,3-pentanediol-monoisobutyrate was studied in details. The reaction is a homogeneous system and carried out in a steady manner. The optimum reaction is as follows: NaOH: 3.0g, temperature: 60 ℃, reaction time: 1.5h. The yield of 2,2,4-trimethyl-1,3-pentanediol-monoisobutyrate is 78.7% and purity is 95.9%(GC).2,2,4-trimethyl-1,3-pentanediol-diisobutyrate(TXIB) was synthesized via the esterification between the above-obtained 2,2,4-trimethyl-1,3-pentanediol-monoisobutyrate and isobutyric acid. The effect of catalyst, reaction time and the dosage of water-carrying agent on the esterification was investigated. The optimum conditions are as follows: the molar ratio of 2,2,4-trimethyl-1,3-pentanediol-monoisobutyrate to isobutyric acid is 1:1.4, the dosage of solid acid QS-8 and petroleum ether(b.p.: 90-120℃) is 0.2% and 15%(based on the total weight of reaction monomers), the reaction time is 7h. Under these conditions, the conversion reached 98.1%, the purity is 99.12%(GC).TXIB with different amounts was added into PVC solution in THF, the rheological properties of PVC/TXIB solution and the physical properties of the PVC/TXIB blended films were characterized. The viscosity of PVC solution is strikingly decreased when introduced TXIB. Tg of the blended films is decreased from 31.0℃ to 6.9℃, when the content of TXIB is increased from 0% to 60%. Break elongation as well as moisture and vapor permeability of the blended films were obviously improved due to the introduction of TXIB.TXIB was applied to investigate the effect on the viscosity of PVAc emulsion with high solid content and properties of of PVAc/TXIB blended films. The results show that both pure PVAc emulsion and the blend emulsions display thin-shearing behaviors, the viscosities of the blend emulsions increased as TXIB content increased at the same shearing rate. The gelation temperature of the blend emulsions decreased with the increasing TXIB content. The introduction of TXIB did not affect the stability of PVAc emulsion under low strain. The blend emulsion shows a better compatibility at a lower temperature and a lower TXIB content.