80717-22-2

Upstream product

• 67-56-1 methanol 
• 592-41-6 1-hexene 
• 6920-22-5 Hexane-1,2-diol 
• 1436-34-6 1,2-Epoxyhexane 
• 96-09-3 styrene oxide 

Relevant academic research and scientific papers

Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction

The function of ammonium salts on the epoxidation performance over Ti-BEA zeolite was investigated in detail. Experiments of alkene epoxidation, side reactions of epoxide and decomposition of H2O2 with or without ammonium salts were designed, and the UV-Vis spectroscopy was employed to analyze the structure of Ti-hydroperoxo species. It is revealed that the ammonia (or amines) dissociated from the ammonium salt would chelate with the linear Ti-η1(OOH) species and form a bridged Ti-η2(OOH)-R species, which is more stable, more weaker in epoxide adsorption and acidity as well. Therefore, side reactions and H2O2 decomposition would be suppressed, and both alkene conversion and epoxide selectivity would be promoted simultaneously. On the other hand, the excessive NH3?H2O (NH3/Ti>1) or NaOH bond with the Ti-η2(OOH)-R species and generate salt-like Ti-η2(OO)-M+ species, resulting in the deactivation of Ti active center. While for ammonium salts, e.g. NH4Cl, the limited dissociation degree along with the acidic environment help the Ti active center to maintain in highly active. In short, this work provides a practical Ti active center tuning method for Ti-BEA zeolite, as well as a thorough understanding of its Ti-hydroperoxo species.

Synthesis of a silicalite-1-coated titanium silicalite-1 (TS-1) zeolite and its catalytic activity in liquid-phase oxidation

Silicalite-1/titanium silicalite-1 (TS-1) composites were synthesized by growing silicalite-1 on the surface of TS-1. Oxidation of 1-hexene was studied using both the silicalite-1/TS-1 composite and uncoated TS-1. The silicalite-1/TS-1 composite showed a higher selectivity toward 1,2-epoxyhexane than uncoated TS-1 because sequential reactions on the external surface of TS-1 were inhibited. The catalytic activity of the silicalite-1/TS-1 composite was almost the same as that of TS-1, suggesting that the silicalite-1 layer is very thin and that the diffusion resistance is negligibly small.

Temperature-dependent immobilization of a tungsten peroxo complex that catalyzes the hydroxymethoxylation of olefins

Abstract A tungsten peroxo complex stabilized by the bidentate picolinato ligand has been synthesized and then immobilized successfully on imidazole-functionalized silica. The immobilized tungsten-based catalyst was employed as an efficient catalyst for the one-pot synthesis of β-alkoxy alcohols from olefins and methanol with H2O2. Regarding the catalyst evaluation and the results of characterization by the various methods, it was demonstrated that the immobilization of tungsten peroxo complex was highly temperature-dependent. The tungsten peroxo complex can dissociate and diffuse into the liquid phase at reaction temperature, resulting in a homogeneous reaction. Nevertheless, the catalytically active species was anchored on the imidazole-functionalized silica by hydrogen bonding as the temperature was lowered to 0°C after the reaction, which thus offered a highly effective approach for recycling the catalyst for consecutive cycles. In addition, various olefins can be converted to the corresponding β-alkoxy alcohols with good conversion and selectivity under relative mild conditions by H2O2. Running hot and cold: A tungsten peroxo complex (see picture) can dissociate and diffuse into the liquid phase at the reaction temperature, resulting in a homogeneous reaction. After reaction, the catalytically active species was anchored on the functionalized silica by hydrogen-bonding as the temperature was lowered to 0°C. This offers an effective approach for catalyst recovery and recycling.

Ring opening of epoxides with alcohols using Fe(Cp)2BF 4 as catalyst

Fe(Cp)2BF4 is an efficient catalyst for the alcoholysis of aromatic, aliphatic, and cyclic epoxides giving excellent yields of the corresponding β-alkoxy alcohols under ambient conditions. The methanolysis of styrene oxide using Fe(Cp)2BF4 as a catalyst (5 mol %) gave excellent yield of 2-methoxy-2-phenylethanol with complete regio-selectivity. The ring opening of cyclic epoxides gave 77-97% yields of trans-β-methoxy alcohols, in 0.5-6 h. The use of 1,2-epoxyhexane and 1,2-epoxydodecane as substrates gave both regioisomers in excellent yields. The first order rate of reaction with respect to catalyst was observed for the kinetics of ring opening of 1,2-epoxyhexane with methanol.

Cyclopentadienyl and pentamethylcyclopentadienyl ruthenium complexes as catalysts for the total deoxygenation of 1,2-hexanediol and glycerol

The ruthenium aqua complexes [cp*Ru(OH2)(N-N)](OTf) (cp* = η5-pentamethylcyclopentadienyl, N-N = 2,2′-bipyridine, phen = 1,10-phenanthroline, OTf- = trifluoromethanesulfonate) and the acetonitrile complex [cpRu(CH 3CN)(bipy)](OTf) (cp = η5-cyclopentadienyl) are water-, acid-, and thermally stable (>200°C) catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOTf as a co-catalyst, they effect the deoxygenation of 1,2-hexanediol to 1-hexanol and hexane. Glycerol is deoxygenated to 1-propanol in up to 18% yield and under more forcing conditions completely deoxygenated to propene. The structure of the acetonitrile pro-catalyst [cpRu(CH3CN)(bipy)](OTf) has been determined by X-ray crystallography (space group P1 (a = 9.3778(10) A; b = 10.7852(10) A; c = 11.1818(13) A; α = 101.718(5)°; β = 114.717(4)°; γ = 102.712(5)°; R = 3.95%).

Oxidation of Olefins with Hydrogen Peroxide and tert-Butyl Hydroperoxide on Ti-Beta Catalyst

The oxidation of a number of linear, branched, and cyclic olefins catalyzed by the large-pore Ti-Beta catalyst in the presence of H2O2 and TBHP as oxidants has been carried out under mild conditions.The influence of the olefin structure on its reactivity towards oxidation has been studied.Depending on the particular olefin structure, the reaction rate was seen to be mostly influenced by the intrinsic reactivity of the double bond, diffusional limitations, or steric factors.The latter were seen to be more pronounced in the oxidations with TBHP, owing to the bulkier Ti-OO-C(CH3)3 species which would be formed inside the zeolite pores.Oxidations with TBHP also proceeded at a lower rate than with H2O2.Close to 100percent selectivities to epoxides were found when TBHP was used as oxygen donor.In the case of H2O2 solvolysis of the oxirane ring in methanol solutions was the major secondary reaction observed.The rate of this reaction was seen to depend on the structure of the epoxide formed in the first step.In both cases, very little peroxide decomposition was observed under the reaction conditions used.

Oxymetallation. Part 15. Oxidation of Hex-1-ene by Thallium(III) Trifluoroacetate in Methanol

Hex-1-ene reacts with thallium(III) acetate in methanol to afford 2-methoxyhexylthallium diacetate which undergoes no appreciable decomposition when kept in methanol at room temperature for one week, but which, upon treatment with solid potassium bromide and a catalytic amount of 2,6-dimethyl-18-crown-6, cleanly affords a high yield of 1-bromo-2-methoxyhexane (1).By contrast, the methoxythalliation adduct obtained with thallium(III) trifluoroacetate undergoes oxidative dethalliation fairly rapidly (ca. 85percent dethalliation after 2 h) to give 1,2-dimethoxyethane (2) and 2-methoxyhexanol (3) as major products.It is suggested that compounds (2) and (3) arise by facile ligand exchange followed by transfer of methoxy- or hydroxy-groups from thallium to C-1 in an SNi process.If the methoxythalliation is carried out with thallium(III) trifluoroacetate in dichloromethane with methanol (2 equiv.) the oxidative dethalliation is complete after only 1 h, but 1-methoxyhexan-2-ol (4) and 2-methoxy-1-trifluoroacetoxyhexane (5) are obtained as additional products.It is suggested that ligand exchange is not effective under these conditions and that dethalliation via an oxonium ion, which leads to compounds (2) - (4), competes with the SNi process which affords compounds (5).Only small amounts (10percent) of hexan-2-one are obtained in the oxidations.