Double-Bond Isomerization of Long Chain Olefins

Bruno, James Edward, B.S., Western Michigan University, 2010 Master of Science, Fall Commencement, 2012 Major: Chemical Engineering Double-Bond Isomerization of Long Chain Olefins Thesis directed by Professor Kerry Dooley Pages in thesis, 54. Words in Abstract, 349. ABSTRACT Alkenyl Succinic Anhydride (ASA) is commonly used in the paper industry as a sizing agent. ASA is produced by reacting maleic anhydride with long-chain internal olefins. Such olefins are only available with the double bond in the terminal position, so an isomerization step is necessary. The isomerization can be catalyzed using solid strong acid catalysts, such as those containing sulfonic acid groups. There were three primary goals for this project: (1) deposit a perfluorinated sulfonic acid polymer (Nafion®) on an Al2O3 of high crush strength; (2) investigate the positional isomerization of 1-hexadecene using such catalysts; (3) test alternative strong acid and base catalysts to determine which catalyst is most effective in the conversion of 1-, 2-, and 3-alkenes to olefins with more internal double bonds. Aluminum oxide catalyst supports were mixed with the strong acid polymer by means of wet impregnation from mixed aqueous/organic and aqueous base solutions. Impregnation from aqueous base gave relatively low polymer weight loadings, but higher acid titers than a comparable industrial catalyst. Impregnations from mixed aqueous/organic solutions gave relatively high weight loadings, but lower acid titers. However, reaction studies confirmed that all of the Al2O3-supported catalysts showed little or no selectivity to internal olefins in the isomerization of 1-hexadecene. Alternative catalysts tested for the isomerization included tungstated zirconia, sulfonated poly(styrene-co-divinylbenzene), proton-form zeolites, and Na/Al2O3. Two zeolites (ZSM-35 and SAPO-11) and two sulfonated poly(styrene-co-divinylbenzenes) (Lewatit K2620 and Amberlyst 35) were relatively selective at producing the target internally double-bonded olefins. Further analysis by GC, GPC, and HNMR showed some skeletal isomerization (branching) and oligomerization. However, silica-supported Nafion gave gave the most branched compounds followed by some sulfonated poly(styrene-co-divinylbenzenes), with zeolites producing the least. HNMR showed chemical shifts associated with branched compounds for each of these catalysts, but the resolution was too poor for good quantitative analysis. GPC showed more dimer for the polymers than the zeolites. These results suggest that some catalysts of lower acid strengths, both sulfonated polymers and zeolites, could be used for this reaction instead of supported Nafion. More information is needed on system temperatures below 130°C and reactions longer than 3 h