阅读说明：本技术 一种化学催化制备甘油二酯的方法 (Method for preparing diglyceride by chemical catalysis ) 是由 王小三 杨壮壮 程昕祎 江聪 董喆 黄健花 常明 于 2020-07-31 设计创作，主要内容包括：本发明涉及油脂深加工领域,具体涉及一种化学催化制备甘油二酯的方法。将油脂、甘油、碱性催化剂和极性溶剂置于反应器中,20℃～90℃温度下,搅拌反应1～10h后,除去碱催化剂、极性溶剂,再经过分子蒸馏得到甘油二酯。本发明使用极性溶剂丙酮、乙腈或叔丁醇作为碱催化油脂和甘油酯交换反应体系的介质,提高甘油的分散性,增加了原料油脂和甘油两互不相溶相的相容性,增大油脂和甘油的接触面积,进而强化酯交换反应的进行,使得催化效率提高,产品得率提高,工艺简单,方法成熟,且成本低,更适于工业化生产。(The invention relates to the field of deep processing of grease, in particular to a method for preparing diglyceride by chemical catalysis. Placing the grease, the glycerol, the alkaline catalyst and the polar solvent into a reactor, stirring and reacting for 1-10 h at the temperature of 20-90 ℃, removing the alkaline catalyst and the polar solvent, and obtaining the diglyceride through molecular distillation. The invention uses polar solvent acetone, acetonitrile or tert-butyl alcohol as medium of the alkali catalysis grease and glyceride exchange reaction system, improves the dispersivity of glycerin, increases the compatibility of the immiscible phases of the raw material grease and glycerin, increases the contact area of the grease and glycerin, further strengthens the ester exchange reaction, improves the catalysis efficiency, improves the product yield, has simple process, mature method and low cost, and is more suitable for industrial production.)

1. A process for the chemocatalytic preparation of diglycerides, comprising:

(1) taking oil, glycerol, an alkaline catalyst and a polar solvent to react in a reactor to obtain a lipid mixture;

(2) distilling the obtained lipid mixture to remove the polar solvent, washing with water to remove the alkaline catalyst, and obtaining the grease rich in diglyceride;

the polar solvent comprises one or more of acetone, acetonitrile and tertiary butanol.

2. The process for the chemical catalytic production of diglycerides according to claim 1, wherein: the oil comprises one or more of vegetable oil, animal oil and microbial oil.

3. The process for the chemical catalytic production of diglycerides according to claim 2, wherein: the vegetable oil comprises one or more of soybean oil, rapeseed oil, rice bran oil, peanut oil, corn oil, cottonseed oil, palm kernel oil, coconut oil, olive oil, sesame oil, castor oil and walnut oil; the animal oil comprises one or more of fish oil, lard, beef tallow, mutton tallow and lanolin oil; the microbial oil comprises one or more of algae oil, yeast oil and bacterial oil.

4. The process for the chemocatalytic production of diglycerides according to claim 1, wherein: the alkaline catalyst comprises one or more of sodium methoxide, sodium hydroxide and potassium hydroxide.

5. The process for the chemocatalytic production of diglycerides according to claim 1, wherein: the molar ratio of the oil to the glycerol is 1: 5-10: 1.

6. The process for the chemocatalytic production of diglycerides according to claim 1, wherein: the mass ratio of the polar solvent to the grease is 0.5: 1-20: 1.

7. The process for the chemocatalytic production of diglycerides according to claim 1, wherein: the addition amount of the alkaline catalyst is 0.05-4% of the total mass of the grease and the glycerin.

8. The process for the chemocatalytic production of diglycerides according to claim 1, wherein: the reaction in the step (1) is carried out at the temperature of 20-90 ℃ for 1-10 h by stirring.

9. The process for the chemocatalytic production of diglycerides according to claim 1, wherein: and (3) removing free fatty acid and monoglyceride in the lipid mixture by molecular distillation or extraction after the distillation and water washing operation in the step (2), so that the content of diglyceride is higher.

Technical Field

The invention relates to the field of deep processing of grease, in particular to a method for preparing diglyceride by chemical catalysis.

Background

Diglyceride (DAG) is a structural lipid with one fatty acid in triglyceride substituted by hydroxyl, has special physiological function, and has similar mouthfeel and flavor with common oil. DAG is divided into two forms of 1,3-DAG and 1,2-DAG, wherein 1,3-DAG is the main form. Animal and human experiments show that 1,3-DAG is ingested by human body and hydrolyzed by digestive enzyme to generate glycerol and free fatty acid, and does not generate monoglyceride to accumulate in the body like triglyceride. Thus, 1, 3-diglycerides have the effect of controlling hyperlipidemia, obesity, etc., as compared with triglycerides containing the same or similar fatty acid composition. In addition, the diglyceride is an emulsifier with strong lipophilicity, and can be applied to the fields of food additives, medicines, cosmetics and the like. The diglyceride is added into the food to replace common edible oil, so that the risks of obesity and the like can be reduced on the basis of not reducing the mouthfeel.

DAG can be produced both chemically and enzymatically. Although the enzyme method has the advantages of mild reaction conditions and few byproducts, the biological enzyme is expensive and has low catalytic efficiency, and the technology of the industrial production of the enzyme method is not mature enough. And the chemical method has various types of catalysts, high catalytic efficiency, lower cost and higher product yield, so that the chemical method for preparing DAG has feasibility and economy in industry.

The production of DAG is mainly a reaction route for transesterification and esterification. Esterification generally involves hydrolysis or saponification of triglyceride oil to free fatty acids, followed by catalytic reaction with glycerol to produce DAG, which results in significant losses during the reaction. The transesterification reaction can directly carry out the catalytic transesterification of triglyceride oil and glycerol (or monoglyceride) to generate DAG, so that the step of hydrolysis or saponification is omitted, the transesterification reaction is more economical, but the problems that the reaction substrate oil and the glycerol have poor two-phase compatibility and are difficult to contact and react exist.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art and provide a method for preparing diglyceride by chemical catalysis.

In order to solve the technical problems, the invention provides the following technical scheme: a method for the chemocatalytic preparation of diglycerides, comprising:

(1) taking oil, glycerol, an alkaline catalyst and a polar solvent to react in a reactor to obtain a lipid mixture;

(2) distilling the obtained lipid mixture to remove the polar solvent, washing with water to remove the alkaline catalyst, and obtaining the grease rich in diglyceride; the polar solvent can be recovered and reused after distillation;

the polar solvent comprises one or more of acetone, acetonitrile and tertiary butanol.

Preferably, the grease comprises one or more of vegetable grease, animal grease and microbial grease.

Preferably, the vegetable oil comprises one or more of soybean oil, rapeseed oil, rice bran oil, peanut oil, corn oil, cottonseed oil, palm kernel oil, coconut oil, olive oil, sesame oil, castor oil and walnut oil; the animal oil comprises one or more of fish oil, lard oil, beef tallow, mutton tallow and lanolin oil; the microbial oil comprises one or more of algae oil, yeast oil and bacterial oil.

Preferably, the basic catalyst comprises one or more of sodium methoxide, sodium hydroxide and potassium hydroxide.

Preferably, the molar ratio of the oil and the glycerol is 1: 5-10: 1.

Preferably, the mass ratio of the polar solvent to the grease is 0.5: 1-20: 1.

Preferably, the addition amount of the alkaline catalyst is 0.05-4% of the total mass of the grease and the glycerin.

Preferably, the reaction in the step (1) is carried out at the temperature of 20-90 ℃ for 1-10 h by stirring.

Preferably, the distillation and water washing operations in step (2) further comprise removing free fatty acids and monoglycerides in the lipid mixture by molecular distillation or extraction, so that the content of diglycerides is higher.

The invention has the beneficial effects that:

(1) the invention uses polar solvent (comprising acetone, acetonitrile and tert-butyl alcohol) as medium of alkali catalysis grease and glyceride exchange reaction system, improves the dispersivity of glycerin, increases the compatibility of two immiscible phases of raw material grease and glycerin, increases the contact area of grease and glycerin, further strengthens the proceeding of ester exchange reaction, improves the catalysis efficiency and improves the product yield.

(2) The solvent system method provides a new idea for the preparation of diglyceride, and compared with the traditional chemical catalysis method, the method has the advantages that the reaction raw materials are mixed and reacted in one step, the reaction is simple and direct, and the loss is reduced; compared with an enzyme catalysis method, the method has the advantages of simpler process, less time consumption, mature method and low cost, and is more suitable for industrial production.

Drawings

FIG. 1 is a liquid chromatogram for composition analysis of the product obtained after molecular distillation in example 1.

FIG. 2 is a liquid chromatogram for composition analysis of the product obtained after molecular distillation in comparative example 1.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.