Cu-Re-Mg-Al four-component catalyst for preparing 1,2-propylene glycol from biodiesel-based crude glycerine by direct hydrogenation and preparation method of catalyst

Abstract

The invention discloses a Cu-Re-Mg-Al four-component catalyst for preparing 1,2-propylene glycol from biodiesel-based crude glycerine by direct hydrogenation and a preparation method of the catalyst. The Cu-Re-Mg-Al four-component catalyst is synthesized by a coprecipitation process in one step and can be directly used for preparing the 1,2-propylene glycol from the biodiesel-based crude glycerine as a raw material after roasting and reduction, the high-efficiency synthesis of 1,2-propylene glycol can be realized under mild and green conditions by adopting the catalyst and the biodiesel-based crude glycerine as raw materials. During the direct hydrogenation at 180 DEG C, 2.0MPa hydrogen pressure and a 75% glycerine water solution, the maximum yield of 1,2-propylene glycol reaches up to 69.2% after the reaction for 10 hours.

Description

technical field [0001] The invention relates to a catalyst for preparing 1,2-propanediol by direct hydrogenation of biodiesel-based crude glycerol and a preparation method thereof, more specifically, a copper catalyst for direct hydrogenation of biodiesel-based crude glycerol to prepare 1,2-propanediol - Rhenium-magnesium-aluminum four-component catalyst and preparation method thereof. Background technique [0002] 1,2-Propylene glycol (1,2-PDO for short) is a colorless, viscous, stable hygroscopic liquid, almost odorless and tasteless, and flammable. Melting point -60°C, boiling point 187.3°C, relative density 1.036 (25 / 4°C), miscible with water, ethanol and various organic solvents, easily oxidized above 150°C. [0003] 1,2-Propanediol is an important raw material of unsaturated polyester, epoxy resin and polyurethane resin. This kind of unsaturated polyester is widely used in surface coatings and reinforced plastics. 1,2-Propanediol is highly viscous, hygroscopic and no...

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Problems solved by technology

[0012] Chinese patent CN200610105255.X discloses a CuO-SiO 2 Catalyst, the catalyst is used for hydrogenation of glycerol at 140-200 degrees and 40-100 atmospheres. This catalyst has a better effect on hydrogenation of glycerol in methanol solution and has high activity in continuous fixed-bed reactors, but methanol solvent Expensive, flammable, toxic

[0017] Chinese patents CN200810120727.8 and CN200810120728.2 disclose a reaction process for preparing propylene glycol by hydrogenation of biodiesel-based crude glycerol under the action of a metal-solid base dual-functional catalyst. Although a batch-type autoclave reaction process is adopted, the reaction time is long Up to 20 hours, the reaction temperature is as high as 180-260 degrees

[0018] Chinese patent CN200810228573.4 discloses a catalyst prepared with Ag and Cu as active components, but the reaction temperature in the examples is above 200 degrees, the yield of propylene glycol is low, and the highest yield of propylene glycol is only 47.5%

Although there are also patent applications using batch-type autoclave reactors, the temperature of the reaction is high or high-purity glycerin is used as a raw material, because the preparation of high-concentration glycerin requires high energy consumption, and at the same time, due to biodiesel-based crude glycerin It also contains a certain amount of residual catalyst (mainly NaOH, Ca(OH) 2 , NaH 2 PO 4 etc.), the refining process of glycerol is complex and costly, so the direct hydrogenation of crude glycerol containing a certain amount of aqueous solution to prepare 1,2-propanediol has higher practical value and potential industrialization

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