Physical and chemical properties and simple use
Colorless and odorless oily liquid, insoluble in mineral oil, slightly soluble in water, soluble in acetone, miscible with ethanol, ether, chloroform, benzene and other organic solvents. Non-toxic, non-irritating, no allergic reaction to skin contact. Dissolving point 3°C, boiling point 258-259°C, relative density 1.1596(20/4°C), refractive index 1.4301, flash point 148.8°C. It is mainly used as cigarette filter adhesive, spice fixing agent, solvent and plasticizer, widely used in tobacco, food, ink, cosmetics, casting, medicine, dyestuff and other industries.
The industrial production of glycerol triacetate generally includes three steps: firstly, glycerol and glacial acetic acid under the action of acidic catalyst will be esterified through heating to obtain semi-finished products of glycerol triacetate; then, through deep esterification of acetic anhydride, to obtain crude products of glycerol triacetate; finally, through appropriate separation and purification, to obtain products of glycerol triacetate. Although the production process of different manufacturers of glycerol triacetate is different, the basic process and principle of their production are more or less the same.
Since the esterification reaction between glycerol and glacial acetic acid under the action of acidic catalyst is a reversible reaction, in order to make glycerol fully esterified, in addition to the moderate excess of glacial acetic acid, the water generated by the reaction should also be removed continuously.
The water generated by the reaction is generally removed by distillation in the industry, and the use of dehydrating agent can improve the effect of water removal. The above reaction using the acidic catalyst reported in the literature many types of catalysts, such as concentrated sulfuric acid, p-toluene sulfonic acid, solid super acid, ionic liquid, etc., but considering the cost and practical application of the effect, the industry generally use concentrated sulfuric acid or p-toluene sulfonic acid as a catalyst.
Since the above esterification reaction is not complete and there is an excess of glacial acetic acid, a simple separation (commonly known as pre-deacidification process) should be carried out after the end of the reaction to remove the excess of glacial acetic acid and the reaction generated in the process of glyceryl acetate monoacetate in order to recycle and apply, and then a semi-finished product of glyceryl triacetate is obtained, the main component is a mixture of glyceryl triacetate and glyceryl diacetate, in which the glyceryl diacetate is deeply esterified by an excess of acetic anhydride.
It is converted to glycerol triacetate to obtain the crude product of glycerol triacetate. The crude product of glycerol triacetate obtained in the previous step is actually a complex mixture, and there are different separation and purification methods according to different quality requirements of the finished product, which generally include three processes: neutralization, crude distillation and refining.
Neutralization is adding appropriate amount of alkali (such as barium hydroxide) to neutralize the acidic catalyst (such as sulfuric acid) added in the esterification reaction; crude distillation is commonly known as high deacidification process, by removing the pre-fraction of crude distillation (mainly acetic acid, acetic anhydride and incompletely esterified glyceryl acetate, which can be recycled and applied), the crude finished product of glyceryl triacetate is obtained; according to different quality requirements, the crude finished product of glyceryl triacetate will be decolorized to remove the acidic catalyst (such as sulfuric acid). The finished products are obtained from the refining treatment of odor and other factors.
Industrial production of glycerol triacetate has two different modes of operation: intermittent and continuous. Compared with batch method, continuous method has lower unit consumption of raw materials, higher utilization rate of equipment, high degree of automation of production and better quality of products, but the investment cost of equipment is higher, which is suitable for large-scale production.
The continuous method is generally used abroad to produce glycerol acetate, but the intermittent method is mostly used in China. There is still a gap with foreign countries in terms of production technology and product quality control, and there is still much room for energy saving and consumption reduction and product quality improvement, so the continuous method is an inevitable choice for the future development of China’s glycerol acetate industry.
China’s production capacity, market situation and development prospects
Although there is still room for further improvement in China’s production technology and product quality of glycerol triacetate, China has certain advantages in terms of labor costs and raw material prices. The actual annual production of glycerol triacetate in China is about half of the world’s annual production.
According to statistics, the global production of glycerol triacetate was 108,000 t in 2010, China’s production of glycerol triacetate was 55,000 t, the United States, Germany and the United Kingdom each had 15,000 t, and about 0.8 million t was produced by Japan and other countries.
At present, the total annual global demand for glycerol triacetate is about 110,000 t, mainly used in tobacco, food, ink, cosmetics, foundry, pharmaceutical and dye fields, of which China’s domestic demand accounts for about 35% of the total global demand, or about 38,500 t.
In recent years, the demand for glyceryl triacetate has maintained a growth rate of 5-10%, and the future demand for glyceryl triacetate will continue to maintain a good growth momentum, with a large space for development, for the following reasons.
Applications in the Tobacco Industry
Glyceryl triacetate is mainly used in the tobacco industry as a binder for cigarette filters, playing the role of plasticizing and curing. At present, the total annual demand of global glyceryl triacetate in tobacco industry is about 35,000t, of which the annual demand of China is about 25,000t. It is expected that the demand in this area will remain basically unchanged in the future.
Application in foundry industry
Glyceryl triacetate is mainly used as a hardener for casting sand. At present, the total annual global demand for glyceryl triacetate in this industry is around 20,000t, of which the annual demand in China is around 0.8 milliont, and it is expected that the demand in this area will maintain a relatively fast growth in the future, with an annual demand growth rate of 8-10%.
Applications in food, flavor, pharmaceutical and cosmetics industries
Glyceryl triacetate is used as a humectant, binder and plasticizer in the food, flavor, pharmaceutical and cosmetic industries. At present, the total annual global demand for glyceryl triacetate in this industry is about 40,000t, of which China’s annual demand is about 0.3 milliont, much lower than the international level. It is expected that China’s demand in this area will maintain a rapid growth in the future, with an expected annual demand growth rate of 10-15%.
Applications in industries such as ink, dyes and plastics processing
Glyceryl triacetate is used as a plasticizer and performance improver in industries such as ink, dye and plastic processing. At present, the total annual global demand for glyceryl triacetate in these industries is about 15,000 t, of which the annual demand in China is about 0.25 million t. It is expected that China’s demand in this area will maintain a relatively fast growth rate, and the annual demand growth rate is expected to be 10%-12%.
From the above, we can see that glyceryl triacetate is widely used, and its demand will keep a high growth rate. It is expected that the global annual demand growth rate will be 5%-10%, and China’s demand growth rate is higher than foreign countries, especially in the food, flavor, pharmaceutical and cosmetic industries.
Gross Profit Estimation
Various types of catalysts are used to synthesize glycerol triacetate, which is calculated here as sulfamic acid. The public works consumption per ton of glyceryl triacetate is about 800 yuan. The current market price of glycerol triacetate is RMB 9000-9500/t, and the gross profit is RMB 700-1200/t.