Synthesis Of Trimethylolpropane Trioleate With Solid Superacid Catalyst SO₄^2-/TiO₂-HZSM-5

Compared to the traditional mineral-based lubricants, with the disadvantages of poorbiodegradability, easy to accumulate and make environmental pollution, trimethylolpropanetrioleate (TMPTO) is an important chemically modified green lubricant, due to its excellentbiodegradability and thermostability is paid more attention. However, because of watercontamination and entrainment, the lubricating oil during the process of processing, handling,storing and recycling is often forming emulsion, resulting in poor liquidity and lubricity, soit requests itself must have excellent anti-emulsification performance.Zeolite HZSM-5with two-way cross-channel, shape-selective catalysis performance,and good application prospect was selected as superacid catalyst carrier. Solid superacidcatalyst SO42-/TiO2-HZSM-5was prepared by the sol-gel process, and which was used tocatalyze the esterification of trimethylolpropane(TMP) and oleic acid (OA).The effects of catalyst preparation conditions, such as precipitation pH, calcinationtemperature, calcination time, of solid superacid SO42-/TiO2-HZSM-5on catalytic activitywere investigated. The results show that: under the preparation conditions of the catalyst thatthe precipitation pH is8, impregnation concentration of sulfuric acid is0.5mol/L andimpregnation time is30min, TMPTO can exhibit excellent properties the esterification rateof is97.6%, oil-water separation time is5min.The solid superacid catalyst SO42-/TiO2-HZSM-5was characterized by IR, XRD, SEM,EDS, BET. The results show that: SO42-/TiO2with the form of nanoparticles are supportedon the surface of HZSM-5, the BET surface area of the catalyst is high up to309.2m2/g,increases45.6m2/g by compared with HZSM-5.The solid acidity of solid superacid catalyst SO42-/TiO2-HZSM-5was characterized byHammett indicator method, the result show that the solid acidity of solid superacid catalystSO42-/TiO2-HZSM-5is-13.8<H0<-12.14, the catalyst reaches the strength of super acid.The results of repeated use show that when solid superacid SO42-/TiO2-HZSM-5catalyst was reused6times, the esterification rate of trimethylolpropane trioleate decreasesby8.8%, the catalyst shows good reusability.Effects of molar ratio of acid to alcohol, catalyst dosage, reaction time, reactiontemperature, and different types of catalysts on esterification were investigated, determined the optimal reaction conditions: molar ratio of acid to alcohol is3.1:1, catalyst dosage is2%,reaction temperature is200℃, reaction time is8h.The product was characterized by IR. The results show that the structure of product isthe same with the standard sample, which confirms that the product is trimethylolpropaneoleate.The thermal stability of trimethylolpropane trioleate was characterized by TG analysis.The results show that the initial decomposition temperature and the termination of thedecomposition temperature are371.6℃and445.5℃, which shows excellent thermostability.The results of physical and chemical properties of trimethylolpropane trioleate showthat: the acid value is9.37mgKOH/g, the hydroxyl value is19.72mgKOH/g, theSaponification value is173.28mgKOH/g, the viscosity at40℃and100℃are49.92mm2/sand10.72mm2/s, the oil and water are completely segregated after5min, which is consistentwith the use of lubricants standard.