- Method for synthesizing BDO by using 2 - device byproduct 2 hydroxymethyl propionaldehyde and 2 -dimethylolpropionic acid
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The invention provides a method for producing BDO by using 2 - byproduct 2 hydroxymethyl propanal, in particular: 2 - hydroxymethyl propanal is condensed under the action of an alkali catalyst, and formaldehyde is condensed to obtain 2 - and 2 dimethylolpropionic aldehyde intermediate which is catalytically oxidized to obtain 2 - and 2 2 - dimethylolpropionic acid. The synthetic route is novel, and by-product BDO hydroxymethyl propanal produced in 2 - process by allyl alcohol method is a starting material and is condensed. 2, 2 Dimethylolpropionic acid is obtained through the oxidation and the like to obtain 2 - and the byproduct of the waste is comprehensively utilized, BDO device three wastes are reduced, a new product can be sold, and the economical efficiency of the device is effectively improved.
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Paragraph 0014; 0051-0053; 0054-0056; 0057-0059; 0060; ...
(2021/09/08)
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- Method for preparing trimethylolethane through continuous condensation hydrogenation method
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The invention relates to a method for preparing trimethylolethane through a continuous condensation hydrogenation method. According to the method, a condensation reaction still for achieving a continuous hydroxy aldehyde addition reaction of an impinging stream reactor, a gas-liquid-solid three-phase drip bed hydrogenation reactor and a bubbling type fluidized bed hydrogenation reactor are involved, and the two hydrogenation reactors are operated in series and contain a novel nickel hydrogenation catalyst and a main ingredient copper-chrome-aluminum-zinc catalyst respectively. It is guaranteed that formaldehyde and propionaldehyde stably generate a 2,2-dihydroxy methyl propyl aldehyde intermediate under organic weak alkali through the continuous impact steam aldol condensation reactor, generated byproducts are reduced, two hydrogenation reactions of different structures have the advantages of being high in conversion rate, simple in process, high in product purity, good in high temperature stability and the like, and the final yield of trimethylolethane can reach 95% or above.
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Paragraph 0008; 0072-0074
(2017/06/02)
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- Self- and cross-aldol condensation of propanal catalyzed by anion-exchange resins in aqueous media
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Carbon-carbon bond formation using strong and weak anion-exchange resins as green catalysts for self- and cross-aldol condensation of propanal in aqueous media was investigated. The reaction pathway followed the route of aldol condensation to a β-hydroxy aldehyde and dehydration to an α,β-unsaturated aldehyde. The resulting products were further converted to hemi-acetal, and/or acetal moieties, which were confirmed by FT-IR and NMR. In self-condensation using strong anion-exchange resin, 97% conversion of propanal was achieved with 95% selectivity to 2-methyl-2-pentenal within 1 h using 0.4 g/mL resin at 35 °C. The conversion and selectivity using weak anion exchanger was lower. During cross-aldol condensation of propanal with formaldehyde, 3-hydroxy-2-methyl-2-hydroxymethylpropanal was obtained as the main product through first and second cross-condensation followed by hydration reaction in acidic aqueous conditions. The strong anion-exchange resin provided maximal propanal conversion of 80.4% to the product with 72.4% selectivity after 7 h reaction at 35 °C and resin concentration of 1.2 g/mL. Using weak anion-exchange resin, the optimal conversion of propanal was 89.9% after 24 h at 0.8 g/mL resin and 35 °C, and the main product was 3-hydroxy-2- methylpropanal by first cross-aldol condensation along with relatively minor amounts of methacrolein and 3-hydroxy-2-methyl-2-hydroxymethylpropanal.
- Pyo, Sang-Hyun,Hedstroem, Martin,Hatti-Kaul, Rajni,Lundmark, Stefan,Rehnberg, Nicola
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experimental part
p. 631 - 637
(2011/12/02)
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