623-50-7Relevant articles and documents
Buechner
, p. 1229,1235 (1965)
A continuous process for glyoxal valorisation using tailored Lewis-acid zeolite catalysts
Dapsens, Pierre Y.,Mondelli, Cecilia,Kusema, Bright T.,Verel, Rene,Perez-Ramirez, Javier
, p. 1176 - 1186 (2014)
The aqueous-phase heterogeneously catalysed isomerisation of bio-oil derived glyoxal is herein introduced as a novel route for the sustainable production of glycolic acid. While commercial ultra-stable Y zeolites displayed only moderate performance, their evaluation enabled us to highlight the crucial role of Lewis acidity in the reaction. Gallium incorporation into these zeolites boosted the glycolic acid yield, although the best catalytic results were obtained over tin-containing MFI-type zeolites, reaching 91% yield of the desired product at full conversion. These materials comprised hydrothermally-synthesised Sn-MFI as well as a novel catalyst obtained by the introduction of tin into silicalite-1 by means of a simpler and more scalable method, i.e. alkaline-assisted metallation. In-depth spectroscopic characterisation of these systems uncovered a substantial similarity of the tin centres obtained by the top-down and bottom-up synthetic approaches. NMR spectroscopic studies gave evidence that the reaction follows a 1,2-hydride shift mechanism solely catalysed by Lewis-acid sites. The Sn-MFI analogue could be reused in 5 cycles without the need for intermediate calcination, did not evidence any tin leaching, and demonstrated suitability for utilisation under continuous-flow operation. The tin-based zeolites exhibited remarkable performance also in alcoholic solvents, leading to the one-pot production of relevant alkyl glycolates.
Preparation method of levocetirizine
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Paragraph 0021-0022, (2020/04/17)
The invention provides a preparation method of levocetirizine. The method comprises the following steps of: the step 1, carrying out a cyclization reaction on (R)-4-chlorodiphenyl methylamine and tris(2-chloroethyl)amine to obtain a compound represented by a formula (I); 2, performing condensation reaction of the compound shown in the formula (I) and 2-ethyl glycolate to obtain a compound shown ina formula (II); and the step 3, converting the compound shown in the formula (II) into levocetirizine. According to the preparation method, (R)-4-chlorodiphenyl methylamine and tris(2-chloroethyl)amine are taken as the initial raw materials, and cyclization reaction, condensation reaction and hydrolysis reaction are carried out so as to obtain levocetirizine. The synthetic route provided by the invention is short, the yield is high, and experimental results show that the yield of the levocetirizine prepared by the method provided by the invention can reach 47%, and the purity can reach 99.7%.
Preparation method of glycolic acid or glycolate
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Paragraph 0152-0154, (2020/09/20)
The invention discloses a preparation method of glycolic acid or glycolate. The method comprises the following steps of: formaldehyde and carbon monoxide are introduced into a reactor containing a reaction solution to carry out polymerization reaction, wherein the reaction solution contains an acid catalyst; after the relative molecular mass of a polymer generated by the polymerization reaction reaches 2,000 and above, the polymerization reaction system is cooled to crystallize and precipitate the generated polymer; solid-liquid separation is carried out on the material in the reactor; and excessive water or alcohol is added into the obtained solid phase to carry out a depolymerization reaction to obtain glycolic acid or glycolate. Compared with the prior art, the method disclosed by the invention is good in process stability, low in energy consumption, good in economic practicability and high in product yield, and has a very good application prospect.
