1732-10-1Relevant articles and documents
FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
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, (2021/06/22)
The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
Efficient Palladium-Catalyzed Carbonylation of 1,3-Dienes: Selective Synthesis of Adipates and Other Aliphatic Diesters
Yang, Ji,Liu, Jiawang,Ge, Yao,Huang, Weiheng,Ferretti, Francesco,Neumann, Helfried,Jiao, Haijun,Franke, Robert,Jackstell, Ralf,Beller, Matthias
supporting information, p. 9527 - 9533 (2021/03/08)
The dicarbonylation of 1,3-butadiene to adipic acid derivatives offers the potential for a more cost-efficient and environmentally benign industrial process. However, the complex reaction network of regioisomeric carbonylation and isomerization pathways, make a selective and direct transformation particularly difficult. Here, we report surprising solvent effects on this palladium-catalysed process in the presence of 1,2-bis-di-tert-butylphosphin-oxylene (dtbpx) ligands, which allow adipate diester formation from 1,3-butadiene, carbon monoxide, and methanol with 97 % selectivity and 100 % atom-economy under scalable conditions. Under optimal conditions a variety of di- and triesters from 1,2- and 1,3-dienes can be obtained in good to excellent yields.
Synthesis of Branched Biolubricant Base Oil from Oleic Acid
Chen, Shuang,Wu, Tingting,Zhao, Chen
, p. 5516 - 5522 (2020/09/07)
The mature manufacturing of synthetic lubricants (poly-α-olefins, PAO) proceeds through oligomerization, polymerization, and hydrogenation reactions of petrochemical ethylene. In this work, we utilize the inexpensive bio-derived oleic acid as raw material to synthesize a crotch-type C45 biolubricant base oil via a full-carbon chain synthesis without carbon loss. It contains several cascade chemical processes: oxidation of oleic acid to azelaic acid (further esterification to dimethyl azelate) and nonanoic acid (both C9 chains). The latter is then selectively hydrogenated to nonanol and brominated to the bromo-Grignard reagent. In a next step, a C45 biolubricant base oil is formed by nucleophilic addition (NPA) of excessive C9 bromo-Grignard reagent with dimethyl azelate, followed by subsequent hydrodeoxygenation. The specific properties of the prepared biolubricant base oil are almost equivalent to those of the commercial lubricant PAO6 (ExxonMobil). This process provides a new promising route for the production of value-added biolubricant base oils.
A general platinum-catalyzed alkoxycarbonylation of olefins
Beller, Matthias,Dühren, Ricarda,Franke, Robert,Ge, Yao,Huang, Weiheng,Jackstell, Ralf,Liu, Jiawang,Neumann, Helfried,Schneider, Carolin,Yang, Ji
supporting information, p. 5235 - 5238 (2020/07/30)
Hydroxy- and alkoxycarbonylation reactions constitute important industrial processes in homogeneous catalysis. Nowadays, palladium complexes constitute state-of-the-art catalysts for these transformations. Herein, we report the first efficient platinum-catalysed alkoxycarbonylations of olefins including sterically hindered and functionalized ones. This atom-efficient catalytic transformation provides straightforward access to a variety of valuable esters in good to excellent yields and often with high selectivities. In kinetic experiments the activities of Pd- and Pt-based catalysts were compared. Even at low catalyst loading, Pt shows high catalytic activity.
Conversion of oleic acid into azelaic and pelargonic acid by a chemo-enzymatic route
Brenna, Elisabetta,Colombo, Danilo,Di Lecce, Giuseppe,Gatti, Francesco G.,Ghezzi, Maria Chiara,Tentori, Francesca,Tessaro, Davide,Viola, Mariacristina
, (2020/04/27)
A chemo-enzymatic approach for the conversion of oleic acid into azelaic and pelargonic acid is herein described. It represents a sustainable alternative to ozonolysis, currently employed at the industrial scale to perform the reaction. Azelaic acid is produced in high chemical purity in 44% isolation yield after three steps, avoiding column chromatography purifications. In the first step, the lipase-mediated generation of peroleic acid in the presence of 35% H2O2 is employed for the self-epoxidation of the unsaturated acid to the corresponding oxirane derivative. This intermediate is submitted to in situ acid-catalyzed opening, to afford 9,10-dihydroxystearic acid, which readily crystallizes from the reaction medium. The chemical oxidation of the diol derivative, using atmospheric oxygen as a stoichiometric oxidant with catalytic quantities of Fe(NO3)3·9·H2O, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), and NaCl, affords 9,10-dioxostearic acid which is cleaved by the action of 35% H2O2 in mild conditions, without requiring any catalyst, to give pelargonic and azelaic acid.
Selective monomethyl esterification of linear dicarboxylic acids with bifunctional alumina catalysts
Santacroce, Veronica,Bigi, Franca,Casnati, Alessandra,Maggi, Raimondo,Storaro, Loretta,Moretti, Elisa,Vaccaro, Luigi,Maestri, Giovanni
supporting information, p. 5764 - 5768 (2016/11/06)
An environmentally friendly protocol for the selective protection of dicarboxylic acids is reported using methanol as a cheap esterifying agent and alumina as a heterogeneous catalyst; the selectivity of the process has been ascribed to a balanced acidity/basicity of the bifunctional alumina catalyst.
Synthesis of ceramides NS and NP with perdeuterated and specifically ω deuterated N-acyl residues
Sonnenberger, Stefan,Lange, Stefan,Langner, Andreas,Neubert, Reinhard H.H.,Dobner, Bodo
, p. 531 - 542 (2016/11/06)
The synthesis of 12 deuterated ceramides with either a deuteration at the last carbon atom of the amide bound fatty acid or a perdeuterated fatty acid chain is described. The ceramides were prepared starting from sphingosine or phytosphingosine and ω deuterated or perdeuterated fatty acids with PyBOP as activating agent in high yields. For the synthesis of the specifically deuterated fatty acids, dicarboxylic acids were transformed into ω deuterated alkyl bromide, which was chain elongated with blocked ω bromo alcohols by copper catalyzed Grignard coupling. Oxidation of regenerated alcohol function yields the ω deuterated fatty acids.
The synthesis of di-carboxylate esters using continuous flow vortex fluidics
Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
, p. 2193 - 2200 (2016/04/19)
A vortex fluidic device (VFD) is effective in mediating the synthesis of di-esters at room temperature. Processing under ambient conditions allows for a simple and efficient synthesis, whilst operating under continuous flow addresses scalability. The rotational speed of the sample tube and the flow rate were critical variables during reaction optimization, and this relates to the behaviour of the fluid flow at a molecular level. Whilst at specific rotational speeds the tube imparts a vibrational response into the fluid flow, the flow rate dictates residence time and the ability to maintain high levels of shear stress. The combination of mechanically induced vibrations, rapid micromixing, high levels of shear stress and water evaporation results in yields up to 90% for 3.25 minutes or less residence time. These results are key for devising greener and more efficient processes both mediated by the VFD and other continuous flow platforms.
Process for preparing a carboxylic acid from a diol or from an epoxide by oxidative cleavage
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Page/Page column 8; 9, (2016/06/28)
A process for preparing a carboxylic acid, by oxidative cleavage of at least one vicinal diol, or an epoxide, wherein the reaction is carried out in the presence of a catalyst and of an oxidizing agent and in the absence of solvent.
Six New Polyacetylenic Alcohols from the Marine Sponges Petrosia sp. and Halichondria sp.
Gabriel, Adeyemi Francis,Li, Zhen,Kusuda, Ryouhei,Tanaka, Chiaki,Miyamoto, Tomofumi
, p. 469 - 475 (2015/09/07)
Six new polyacetylenic alcohols, termed strongylotriols A and B; pellynols J, K, and L; and isopellynol A, together with three known polyacetylenic alcohols, pellynols A, B, and C were isolated from the marine sponges Petrosia sp., and Halichondria sp. collected in Okinawa, Japan. Their planer structures were determined based on 2D-NMR and mass spectrometric analysis of the degraded products by RuCl3 oxidation. The absolute stereochemistry of isolates was examined by their Mosher's esters. The strongylotriols were found to be optically pure compounds, whereas the pellynols are diastereomeric mixtures at the C-6 position. Proliferation experiments using the HeLa and K562 cell lines suggested that the essential structural units for activity are the "hexa-2,4-diyn-1,6-diol" and "pent-1-en-4-yn-3-ol" on the termini.