Method for preparing gamma-valerolactone by transferring and hydrogenating levulinic acid and ester thereof

Abstract

The invention discloses a method for preparing gamma-valerolactone by transferring and hydrogenating levulinic acid and ester thereof, and relates to gamma-valerolactone. The method includes adding organic alcohol into a reaction substrate to obtain alcoholic solution used as raw material liquid; placing the raw material liquid into a high-pressure reaction kettle, adding metal oxide catalysts into the high-pressure reaction kettle and enabling the raw material liquid and the metal oxide catalysts to carry out heating reaction so as to obtain the gamma-valerolactone which is a target product. The method has the advantages that alcohol is used as a hydrogen donor and a reaction medium simultaneously, external hydrogen sources and other solvents are omitted, a reaction system is simple, and the method is favorable for separation of the target product; the levulinic acid and the ester thereof can be selectively reduced in a catalytic transferring and hydrogenation mode, transfer and hydrogenation are high in selectivity for ketone groups, and accordingly excessive hydrogenation products can be prevented; cheap and easily available metal oxides are used as catalysts, particularly, the levulinic acid and the ester thereof can be efficiently and selectively reduced under a super-critical condition, and other catalytic promoters are omitted.

Description

technical field [0001] The invention relates to gamma-valerolactone, in particular to a method for preparing gamma-valerolactone through transfer hydrogenation of levulinic acid and its esters. Background technique [0002] γ-valerolactone is also considered as a platform compound with a very wide range of potential applications, and has received more and more attention from researchers in recent years. γ-valerolactone is a non-toxic, biodegradable, stable and safe compound that is easy to store in large quantities. It is often used as a spice and food additive; a variety of high value-added chemicals can be converted from γ-valerolactone Compared with ethanol, γ-valerolactone has a higher boiling point (207°C), flash point (96°C), low volatility and high calorific value, so γ-valerolactone is more suitable for use as a vaporizer. Diesel oxygen enhancer and additive, and use γ-valerolactone as raw material to synthesize and refine various liquid fuels that meet the requirem...

AI Technical Summary

Problems solved by technology

On the one hand, most of the existing processes for producing γ-valerolactone use expensive noble metal catalysts. Although the catalytic efficiency is high, it generally requires relatively harsh high-temperature and high-pressure reaction conditions to achieve the ideal γ-valerolactone. Yield

In order to reduce levulinic acid under milder conditions, it is generally necessary to add some additional accelerators (such as basic compounds), which inevitably complicates the reaction system and increases the difficulty of separating the target product

On the other hand, the direct hydrogenation reduction of levulinic acid tends to easily produce over-reduction product 2-methyltetrahydrofuran, which is extremely easy to peroxidize in the air, and its peroxidation product is an extremely flammable and explosive dangerous substance. This is a problem that cannot be ignored in the γ-valerolactone process

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