91547-99-8Relevant articles and documents
Dioxomolybdenum(VI) and -tungsten(VI) Complexes with Multidentate Aminobisphenol Ligands as Catalysts for Olefin Epoxidation
Dup, Antoine,Hossain, Md. Kamal,Schachner, J?rg A.,Belaj, Ferdinand,Lehtonen, Ari,Nordlander, Ebbe,M?sch-Zanetti, Nadia C.
, p. 3572 - 3579 (2015)
The synthesis of four molybdenum and tungsten complexes bearing tetradentate tripodal amino bisphenolate ligands with either hydroxyethylene (1a) or hydroxyglycolene (1b) substituents is reported. The molybdenum dioxo complexes [MoO2L] (L = 2a, 2b) and tungsten complexes [WO2L] (3a, 3b) were synthesized using [MoO2(acac)2] and [W(eg)3] (eg = 1,2-ethanediolato, ethylene glycolate), respectively, as precursors. All complexes were characterized by spectroscopic means as well as by single-crystal X-ray diffraction analyses. The latter reveal, in all cases, hexacoordinate complexes in which the hydrogen atom of the hydroxy group is involved in hydrogen bonding with one of the metal oxo groups. In the case of the glycol substituent, the ether oxygen atom is coordinated to the metal whereas the hydroxy group remains uncoordinated. The complexes were tested as catalysts in the epoxidation of cyclooctene under eco-friendly conditions, using an aqueous solution of H2O2 as the oxidant and dimethyl carbonate (DMC) as solvent or neat conditions, as substitutes for chlorinated solvents. Molybdenum complexes 2a and 2b showed good catalytic activity using H2O2 without added solvent, and tungsten complexes 3a and 3b showed very high activity in the epoxidation of cyclooctene using H2O2 and DMC as solvents. Four new molybdenum and tungsten complexes bearing tetradentate tripodal amino bisphenolate ligands with either hydroxyethylene or hydroxyglycolene substituents were synthesized and found to catalyze olefin epoxidation reactions under eco-friendly conditions.
Unraveling the role of the lacunar Na7PW11O39 catalyst in the oxidation of terpene alcohols with hydrogen peroxide at room temperature
Vilanculo, Castelo B.,Da Silva, Márcio J.
, p. 2813 - 2820 (2020/03/03)
In this work, we have assessed the activity of various Keggin heteropolyacid (HPA) salts in a new one-pot synthesis route of valuable products, which were obtained from the oxidation of terpenic alcohols (i.e., aldehyde, epoxide, and diepoxide), using a green oxidant (i.e., hydrogen peroxide) at mild conditions (i.e., room temperature). Lacunar Keggin HPA sodium salts were the goal catalysts investigated in this reaction. Starting from the HPAs (H3PW12O40, H3PMo12O40, and H4SiW12O40), we synthesized lacunar sodium salts (Na7PW11O39, Na7PW11O39 and Na8SiW11O39) and a saturated salt (Na3PW12O40). All of them were investigated in oxidation reactions in a homogeneous phase with nerol as a model molecule. Na7PW11O39 was the most active and selective towards the oxidation products. All the catalysts were characterized by FT-IR, TG/DSC, BET, XRD, and SEM-EDS analyses and potentiometric titration. The main reaction parameters were assessed. Geraniol, α-terpineol, β-citronellol and borneol were also successfully oxidized. Special attention was dedicated to correlating the composition and properties of the catalysts with their activity.
Method for synthesizing carvacrol from dipentene dioxide
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Paragraph 0017; 0019; 0021; 0022, (2019/01/24)
The invention discloses a method for synthesizing carvacrol from dipentene dioxide. The method comprises the following steps: step 1, utilizing the dipentene dioxide as a raw material and reducing thedipentene dioxide in a solvent A through a sodium borohydride water solution to obtain alpha,alpha,6-trimethyl-7-oxa bicyclo(4.1.0)heptane-3-methyl alcohol and 1,3,3-trimethyl-2-oxa bicyclo(2.2.2)octane-6-alcohol; step 2, dehydrating and rearranging the alpha,alpha,6-trimethyl-7-oxa bicyclo(4.1.0)heptane-3-methyl alcohol and 1,3,3-trimethyl-2-oxa bicyclo(2.2.2)octane-6-alcohol which are obtainedin step 1 through acid catalysis to obtain iso-dihydrocarvone; step 3, dissolving the iso-dihydrocarvone obtained in step 2 and a carbon-based compound catalyst into a solvent and heating the mixtureto generate dehydrogenation oxidation reaction, generating carvacrol, filtering the carvocrol to separate the carbon-based compound catalyst and performing reduced pressure rectification on filtrate to obtain a carvacrol finished product. The acid, the carbon-based compound catalyst and the solvent in the method disclosed by the invention all can be recycled, so that cost is reduced; the raw material of the dipentene dioxide in the method disclosed by the invention is an auxiliary product of the company, so that regeneration and comprehensive utilization of byproducts are achieved, and economic value of the byproducts is improved.
