Synthesis And Application Of β-mvrcene Derivatives By Diels-Alder Reaction

In this paper, β-myrcene was used as the raw material to synthesize an environmentalfriendly plasticiser and an antimicrobial amide. According to the esterification of plasticisersynthetization, a load catalyst was prepared. The research results as follows:Firstly, a new kind of ionic liquid catalyst [HSO₃-bmim]+[HSO4]-/ZrO₂was prepared byloading the self-made ionic liquid [HSO₃-bmim]+[HSO₄]-on the surface of the carrier ZrO₂which was synthetized by hydrothermal method. The results of XRD, IR and TG showed thatthe capacity of ionic liquid [HSO₃-bmim]+[HSO₄]-reached21.01%with a good thermalstability and reutilization property, besides, the ionic liquid didn’t have an obvious influence onthe crystal of ZrO₂. Catalytic performance of the catalyst was studied by esterification ofmaleic anhydride and iso-octanol, the conversion rate of maleic anhydride reached99.8%under the optimum condition of reaction temperature140℃, maleic anhydride4.9g,iso-octanol26g, catalyst0.8g and reaction time100min. On the other hand, The conversionrate could still reach94.9%after9times reused, which was superior than ionic liquid[HSO3-bmim]+[HSO4]-.Secondly, Bis（2-ethylhexyl）-4-（4-methylpent-3-enyl）cyclohex-4-ene-1,2-dicarboxylate（MYMIM） was synthetized through the reaction of iso-octanol and5-（4-methylpent-3-enyl）-3a,4,7,7a-tetrahydroisobenzofuran-1,3-dione （MYM） produced fromDiels-Alder reaction between β-myrcene and maleic anhydride. The results of IR, GC-MS andNMR analysis for MYM and MYMIM showed that the MYMIM were target compounds. Theoptimum esterification condition was as follows when [HSO₃-bmim]+[HSO₄]-/ZrO₂as catalyst:wcatalyst/wtotal=0.7%, wmethanol/w（MYM+iso-octanol）=15%，nMYM︰niso-octanol=1︰4, reaction time:100min under reflux temperature. The plastification of MYMIM indicated that the lowtemperature resistance of MYMIM was much better than DOP，which made MYMIM theprimary plasticiser in PVC. Finally,4-（4-methylpent-3-enyl）cyclohex-4-ene-1,2-dicarboxamide was synthesizedthrough Diels-Alder reaction by β-myrcene and dimethyl maleate and a subsequentammonolysis reaction. The results of IR, GC-MS and NMR analysis showed that the productswere target compounds. The productivity of dimethyl4-（4-methylpent-3-enyl）cyclohex-4-ene-1,2-dicarboxylate reached88.1%, and the selectivity was97.5%without catalyst underthe optimum Diels-Alder reaction condition of reaction temperature150℃and reaction time3h. In addition, the productivity of dimethyl4-（4-methylpent-3-enyl）cyclohex-4-ene-1,2-dicarboxylate reached88.7%, with methanol as solvent under the optimum ammonolysisreaction condition of ammonia pressure0.4MPa and reaction time18h. The antibacterialactivity of4-（4-methylpent-3-enyl）cyclohex-4-ene-1,2-dicarboxamide was also been studied,which showed that there was an significant antibacterial effect on staphylococcus aureus.