What is diglycerol fatty acid ester?

Diglycerol fatty acid ester refers to a substance produced by the reaction of glycerol and fatty acids. There are monoesters, diesters, triesters and other oils. It is widely used in daily life. At room temperature, saturated fatty esters will not undergo oxidation reactions. Only at temperatures above 100 degrees will they become oxides and produce ketones or spasmoyl compounds. Let’s take a look at this aspect.

Glycerol fatty acid ester properties/

Appearance: Visual inspection. It is easily soluble in chloroform, ether or benzene, soluble in petroleum ether, and almost insoluble in water or ethanol. Melting point: According to the melting point determination method, the results are: Type 34: 33-35°C; Type 36: 35-37°C; Type 38: 37-39°C; Type 40: 39-41°C. Acid value: Check according to the acid value test method, not more than 1.0. Iodine value: checked by iodine value inspection method, no more than 2.0. Saponification value: checked by saponification value inspection method, as follows: 34 type 225 ~ 235; 36 type 220 ~ 230; 38 and 40 types 215 ~ 230. Hydroxyl value: Take about 1g of the substance, weigh it accurately, place it in a 250ml dry conical flask with a condenser, accurately add 5ml of acetic anhydride pyridine solution (1→4), place it in a water bath and reflux for 1 hour, then add 10ml of water from the condenser mouth; shake well, continue heating for 10 minutes, cool, rinse the inner wall and bottleneck of the condenser with 25ml of neutral ethanol (neutral to phenolphthalein indicator solution), add 1ml of phenolphthalein indicator solution, titrate with ethanol-based potassium hydroxide solution (0.5mol/L), and do a blank test at the same time. The volume (ml) of ethanol-based potassium hydroxide solution (0.5molL) consumed by the test sample is A, the volume (ml) consumed in the blank test is B, the weight (g) of the test sample is G, and the acid value is D. Calculate according to the following formula. The hydroxyl value is not more than 6.0.

Oxidation reaction

At room temperature, saturated fatty esters hardly undergo oxidation reactions. At high temperatures above 100°C, they can slowly oxidize to form peroxides and produce ketones or hydroxyl compounds.

Thermal decomposition

Fatty acids will undergo thermal decomposition at high temperatures to produce carboxylic acids and olefins.

Synthesis principle:

It is prepared by esterification reaction of fatty acid (RCOOH) and glycerol (C3H8O3) in the presence of a catalyst. Different glycerides can be produced by using different fatty acids.

The reaction formula is:

RCOOH catalyst-0.1MPa C12H24O2 C18H36O2 C3H8O3 C3H5O3 (COR) 3 H2O 218℃

The main function of the catalyst is to increase the hydrogen ions and hydroxide ions that are beneficial to the hydrolysis reaction, promote the emulsification of water in the oil, increase the contact area between water and oil, and facilitate the hydrolysis reaction. It will not change the limit of reaction equilibrium and has nothing to do with the amount added. It only accelerates the reaction. Under the same conditions, the amount of catalyst added is inversely proportional to the time to reach equilibrium.