7378-37-2Relevant academic research and scientific papers
Supported H4SiW12O40 catalysts for α-pinene isomerization
Szuecs-Balazs, Jozsef-Zsolt,Coros, Maria,Woiczechowski-Pop, Adrian,Blanita, Gabriela,Vlassa, Mircea
, p. 1208 - 1217 (2012/11/13)
The heterogeneous isomerization of α-pinene was studied at 100, 130 and 160°C using 10% supported H4SiW12O40 (SiW) on SiO2, TiO2 and HZSM-5. The effect of the reaction temperature and the concentratio
Oxidation of α-pinene by atmospheric oxygen in the supercritical CO2-ethyl acetate system in the presence of Co(II) complexes
Anikeev,Ilina,Kurbakova,Nefedov,Volcho,Salakhutdinov
experimental part, p. 190 - 195 (2012/03/12)
The reactivity of monoterpene α-pinene in a flow reactor in the presence of cobalt catalyst in a complex supercritical solvent consisting of CO2 and ethyl acetate is studied over the temperature range of 190-320°C and a pressure range of 110-125 atm. It was found that the main isomerization products include compounds with bicyclo[2.2.1]heptane and p-menthane backbones; the reaction is accompanied by partial racemization. The formation of oxidation products is observed in the presence of air, with epoxydation rather than allylic oxidation being the predominant process at the first stage. The oxidized products (campholenic aldehyde, verbenone, pinocamphone) are shown to be formed with a high enantioselectivity; the formation of acetoxylation products is observed at temperatures above 200°C.
Cloning and characterization of Pfl-1841, a 2-methylenebornane synthase in Pseudomonas fluorescens PfO-1
Chou, Wayne K.W.,Ikeda, Haruo,Cane, David E.
supporting information; experimental part, p. 6627 - 6632 (2011/10/04)
The pfl-1841 gene from Pseudomonas fluorescens PfO-1 is the only gene in any of the three sequenced genomes of the Gram-negative bacterium P. fluorescens, that is, annotated as a putative terpene synthase. The predicted Pfl-1841 protein, which harbors the two strictly conserved divalent metal binding domains found in all terpene cyclases, is closely related to several known or presumed 2-methylisoborneol synthases, with the closest match being to the MOL protein of Micromonaspora olivasterospora KY11048 that has been implicated as a 2-methylenebornane synthase. A synthetic gene encoding P. fluorescens Pfl-1841 and optimized for expression in Escherichia coli was expressed and purified as an N-terminal His6-tagged protein. Incubation of recombinant Pfl-1841 with 2-methylgeranyl diphosphate produced 2-methylenebornane as the major product accompanied by 1-methylcamphene as well as other minor, monomethyl-homomonoterpene hydrocarbons and alcohols. The steady-state kinetic parameters for the Pfl-1841-catalyzed reaction were K M=110±13 nM and kcat=2.4±0.1×10 -2 s-1. Attempts to identify the P. fluorescens SAM-dependent 2-methylgeranyl diphosphate synthase have so far been unsuccessful.
Generation of acid sites on silica-supported rare earth oxide catalysts: Structural characterization and catalysis for α-pinene isomerization
Yamamoto, Takashi,Matsuyama, Takahiro,Tanaka, Tsunehiro,Funabiki, Takuzo,Yoshida, Satohiro
, p. 2841 - 2849 (2007/10/03)
Silica-supported rare earth oxide catalysts (Ln/SiO2; Ln = La, Ce, Pr, Sm, Eu, Tb, Yb and Y), loading amounts of which were 3.4 mmol g (support)- 1, were characterized by α-pinene isomerization, temperature-programmed desorption (TPD), Fourier transform infrared (FTIR), X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), thermogravimetric-differential thermal analysis (TG-DTA) and Raman spectroscopy. In the lanthanoid series, the catalytic activity increased with atomic number from 57La to 70Yb, except for Ce. All the Ln/SiO2 catalysts, except for Ce, were amorphous. On the surface of the catalyst, Ln-O-Si and Ln-O-Ln linkages formed, the ratio of which varied with the loaded element. The ratio of Ln-O-Si linkage increases with stronger affinity among LnO(n) units and SiO4 tetrahedra, and the affinity depends on the size of Ln3+. With increasing ratio of Ln-O-Si to Ln-O-Ln linkage, the catalytic activity increases. Silica-supported yttrium oxide catalyst, the trivalent ion radius of which is quite similar to that of ytterbium, exhibited the same activity as that of Yb/SiO2. Raman spectroscopic characterization revealed that excess loading of Yb atoms on SiO2-support block Yb-O-Si linkage to form Yb2O3 fine particles. When Yb/SiO2 was pretreated at 1273 K, fine ytterbium silicate crystallites formed. Ln-O-Si linkage without a long-ranged ordering structure was the active site for α-pinene isomerization.
Liquid-phase isomerization of α-pinene on a natural clinoptilolite
Allakhverdiev,Sokolova,Gunduz,Kul'kova
, p. 1647 - 1650 (2007/10/03)
The liquid-phase isomerization of α-pinene on a suspended powder (50-100 μm) of a natural clinoptilolite is studied. It is found that thermoevacuation at 500°C decreases the catalyst's activity and selectivity. The surface acidity decreases, whereas the surface concentration of Fe2+ ions increases. The reaction mechanism is proposed.
Acidic property of FSM-16
Yamamoto, Takashi,Tanaka, Tsunehiro,Funabiki, Takuzo,Yoshida, Satohiro
, p. 5830 - 5839 (2007/10/03)
Siliceous FSM-16 possesses acid sites to catalyze but-1-ene isomerization to produce but-2-ene (cis/trans = 1.4-1.7) at 323 K and 2,6,6- trimethylbicyclo[3.1.1]hept-2-ene (α-pinene) isomerization at 303 K. Catalytic activity was dependent upon heat treatment and reached a maximum at 673 K. The maximum acid strength was invariably H0 = -3.0 independent of the pretreatment temperatures. The acidity was much reduced by calcination at higher temperatures, but restored by water treatment at 353 K as long as the FSM-16 retained its structure.
Structural Effects in Solvolytic Reactions. 49. Steric Effects as a Major Factor in the Exo:Endo Rate Ratios for the Solvolysis of 2,7,7-Trimethyl- and 2,6,6-Trimethyl-2-norbornyl p-Nitrobenzoates
Brown, Herbert C.,Ikegami, Shiro,Jagt, Dawid L. Vander
, p. 1165 - 1171 (2007/10/02)
The exo:endo rate ratio for solvolysis, in 80percent aqueous acetone at 25 deg C, decreases from 885 for 2-methyl-2-norbornyl p-nitrobenzoate to 6.1 for 2,7,7-trimethyl-2-norbornyl p-nitrobenzoate.On the other hand, it increases remarkably to 3 630 000 in the case of 2,6,6-trimethyl-2-norbornyl p-nitrobenzoate.These changes are clearly attributable to steric effects caused by the syn methyl group at the 7- and 6-positions, respectively.In the 2,7,7-trimethyl-2-norbornyl system, the very low exo:endo rate ratio arises primarily from an increased rate of solvolysis of the endo isomer, attributed to relief in steric strain, involving the syn 7-methyl and exo 2-methyl groups, during ionization.The extremely large exo:endo rate ratio in the 2,6,6-trimethyl-2-norbornyl system is attributed to the high rate of solvolysis of the exo isomer, caused by the relief in steric strain involving the endo 2-methyl and endo 6-methyl groups, as well as an especially slow rate for the endo isomer, caused by enhanced steric retardation of ionization.Thus, these results show clearly that exo:endo rate ratios can be strongly affected by steric effects in the rigid norbornyl system.
