Process for preparing acrolein by glycerin dewatering

Abstract

This invention relates to acidity zeolite catalyst used for glycerol dehydration to perpare acrolein and the reaction craft. Glycerine directly dehydrate to generate acrolein under the condition of acidity zeolite catalyst, 200 to 500deg temperature, 0.001 to 3.0MPa pressure and 0.1 to 100.0h - 1 liquid airspeed, at the same time produce byproduct pyruvic alcohol. The raw material raw glycerine could be mixed liquor of water solution, alcosol, fatty acid ester solution at any ratio.

Description

technical field [0001] The invention relates to a method for preparing acrolein by dehydrating glycerin. Specifically, acidic zeolite is used as a catalyst, at a temperature of 200-500°C, a pressure of 0.001-3.0MPa and a liquid space velocity of 0.1-100.0h -1 Under certain reaction conditions, glycerol is directly dehydrated to generate acrolein. Background technique [0002] Acrolein is an important fine chemical intermediate, mainly used in the production of pesticide imidacloprid, pharmaceutical antineoplastic drug dibromopropanal, feed additive methionine, and fungicide glutaraldehyde; acrolein can be oxidized to produce acrylic acid, which can be further synthesized into acrylic acid Esters; 1,3-propanediol can be synthesized by hydration reduction; propanol can be produced by reduction, and it is an important intermediate for the synthesis of perfumes, pharmaceuticals, allylthiourea, and allyl isothiocyanate. [0003] Industrially, acrolein is mainly produced by the o...

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Problems solved by technology

[0005] FR 695931 reported that phosphates such as iron phosphate and lithium phosphate were supported on pumice, and the gas-phase dehydration reaction of glycerol was carried out at a temperature above 300°C, especially at 400-420°C. The highest yield of acrolein could be as high as 75-80%. According to the report of Degussa Company (US 5426249 and CN1034803C), this result cannot be repeated. In fact, the yield of acrolein is only 1% to 3% at 300°C. Even at 400°C, the yield of acrolein is only 30%. ~35%, mainly by-products such as allyl alcohol, acetaldehyde and propionaldehyde

Degussa company reported catalysts such as phosphoric acid supported alumina, HZSM-5, HY in the patent US 5426249 and CN 1034803C, when the acrolein selectivity was about 71%, the conversion rate of glycerin was only 19%, and the conversion rate was low

Although WO 087084A2 in 2006 also reported phosphoric acid-supported alumina, but the highest yield of acrolein was only 54.5%. The patent also reported oxides and supported catalysts such as ZrO 2 / SO 4 、Nafion / SiO2 2 , ZrO 2 / PO 4 , ZrO 2 / WO 3 , zirconium sulfate, etc., but the yield of acrolein is generally low, and the content of hydroxyacetone in the product is relatively high