Font Size: a A A

Metal Oxide Catalysts Tert-butyl Hydrogen Peroxide Oxidation Of Olefin Synthesis Vicinal Diol

Posted on:2008-09-13Degree:MasterType:Thesis
Country:ChinaCandidate:Q N ZhangFull Text:PDF
GTID:2191360215492406Subject:Physical chemistry
Abstract/Summary:PDF Full Text Request
Cyclohexanediol is one of the most important organic chemical raw materials. It isusually used to produce polyester,medicine,pesticide fine chemicals and the like. Withthe fast development of oil chemical industry, chemists are paying much attention to theexploitation and utilization of olefin ramifications.In this paper, we introduced a new effective and environmental protective method inwhich selective oxidation of cyclohexene by t-butyl hydroperoxide (TBHP) to preparetrans-1,2-cyclohexanediol was performed over V2O5, Nb2O5, Cr2O3, MoO3, and WO3catalysts. The precursors of ammonium metavanadate, chromium nitrate, ammoniummolybdenum, ammonium tungstate and titanium tetrachloride were uesd to systhesis ofthese catalysts. Niobium oxide and silicon oxide directly came from commercial products.XRD was used to analyze the crystal structures of these catalysts. Using cyclohexene asthe probe moleucule to find high selectivive catalyst of cyclohexanediol formation fromVOs, activitives of these catalysts were as follow: MoO3>VO5>Nb2O5>Cr2O3>WO3.MoO3 was the most effective catalyst. As TBHP was partially decomposed by VO5, theconversion of cyclohexene was decreased and the activity of VO5 was lower thanMoO3. Then we discussed some factors that the amount of catalysts, reaction temperature,reaction time, the concentration of TBHP, and the additive quantity of KOH to influencecyclohexene conversion and cyclohexanediol selectivity. The results indicated that theconversion of cyclohexene was 99% and the cyclohexanediol was 98% on MoO3 with a1:1 molar ratio of cyclohexene to 65%TBHP for 12h at 90℃. It was also to found a littleamount of cyclohexenol and cyclohexenone as byproducts.In this paper we also investigated the reaction mechanism of selective oxidation ofselective oxidation of cyclohexene by TBHP to prepare trans-1,2-cyclohexanediol. Bychanging concertration of TBHP and temperature per hour, we achieved that cyclohexenewas first oxidated to form cyclohexene oxide over MoO3, then cyclohexene oxide washydrolyzed to form trans-1,2-cyclohexanediol. We investigated selective oxidations of1-hexene, allyl chloride,α-methylstyrene, limonene, 1,5-cyclooctadiene, cyclopentene,3-methyl-2-buten-1-ol, cyclooctene by TBHP with a 1:1 molar ratio of alkene to65% TBHP for 10h at 80℃. It indicated that MoO3 was active to oxidations of double bands of hexad rings to hexanediol and alkene to cycloxides, but inactive in hydrolysis ofthree-membered rings to form vicinal trans-diols.We further designed selective oxidation of cyclohexene to trans-1,2-cyclohexanediol.The volume of reactor was 200L with vapor heating.
Keywords/Search Tags:cyclohexene, selective oxidation, t-butyl hydroperoxide, trans-1,2-cyc-lohexanediol, metallic oxides
PDF Full Text Request
Related items