Introduce you to the green plasticizer tributyl citrate（TBC）

Brief introduction of Tributyl citrate

Tributyl citrate（TBC）is an ester compound, and its structure is shown in the following figure.

Physical properties: colorless or yellowish oily transparent liquid at room temperature, nontoxic, miscible with various organic solvents and insoluble in water;

Chemical properties: the molecular formula is C₁₈H₃₂O₇, also known as tributyl 3- hydroxy -3- carboxyglutarate. This kind of ester compound is usually esterified by citric acid and n-butanol under the action of catalyst. In chemical structure, tributyl citrate contains a citraconic acid skeleton, in which three hydroxyl groups are esterified by n-butyl, so it has high compatibility with resin.

Development history of TBC

Tributyl citrate is obtained by esterification of citric acid and n-butanol under certain reaction conditions and in the presence of catalyst. The catalysts needed for synthesis must be acid catalysts, including inorganic acids and acid salts, organic acids, solid acids, etc. Among them, concentrated sulfuric acid is the most widely used acid catalyst because of its low price and high activity, but its products are dark in color and seriously corrode equipment, which also has a certain impact on the environment. Therefore, replacing concentrated sulfuric acid with environment-friendly acid catalyst has become the development direction[5,6].

Application field of TBC

1. Plasticizer

Tributyl citrate is an environment-friendly plasticizer, which can replace phthalate plasticizer, weaken the intermolecular force of polymer, reduce the melting temperature and guest viscosity, improve its molding and processing performance, and endow plastic products with flexibility and other necessary properties within the use temperature range[1,2].

2. Food field

Citric acid is used as a food additive, which can strengthen the feeling, texture and color of food, and can also prolong the shelf life and stability of food[8]. It can be used for food preservation, emulsification and thickening, and is widely used in the preparation of condiment drinks, frozen foods, jellies, sweets and other foods[9].

3. Medical and health fields

Tributyl citrate is a common pharmaceutical adjuvant. Because of its excellent solubility and high compatibility, it can improve the solubility and synthesis stability of pharmaceutical raw materials[3]. It can be used as both a drug dropping agent and a solvent, and also plays a certain role in seasoning. It is used to make various oral solutions, oral gums and injections[4]. In addition, polymer products made of TBC as plasticizer can also be applied to the medical field, such as PVC for needle cannula and other medical device parts.

4. The field of cosmetics

Triglyceride citrate is often used in main cosmetics and personal care products because of its colorless and odorless properties. Its stability can strengthen the texture and guarantee period of cosmetics. It is also used as a solvent, lubricant, essence and spice flavoring agent to improve the texture, wettability, freshness and smell of products, and is widely used in lipstick, lipstick, make-up water, cream, emulsion and perfume[7].

References

[1] Xu Yongqiang, Gao Qiang. Research progress on green synthesis of new generation environmentally friendly plasticizer tributyl citrate [J]. Science and Technology Review, 2019, 37(12): 79-85.

[2] Shi Wancong. Toxicity of plasticizers and related restrictive regulations [J]. Plastic Additives, 2010, (03): 43-47.

[3] Long Jinqiao, Chen Huani. Catalytic synthesis of green plasticizer tributyl citrate [J]. Science and Technology Bulletin, 2012, 28(11): 126-129.

[4] Li Yaocang, Ma Hongxia. Synthesis and application of environmentally friendly plasticizer tributyl citrate [J]. Plastics Industry, 2012, 40(10): 24-27.

[5] Xiao Ming, Research progress on synthesis process of plasticizer tributyl citrate [J]. Fine and Specialty Chemicals, 2021, 29(03): 34-36.

[6] P. Gupta, S. Paul, Solid acid: a green alternative to acid catalysis [J] Current Catalysis, 2014, 236: 153-170.

[7] Cui Xiaoming. New progress in the research on the synthesis process of tributyl citrate [J]. Plastic Additives, 2016(1): 12-14, 20.

[8] Lv Shiguang. Handbook of Plastic Additives [M]. Beijing: Light Industry Press, 1986, 150-153.

[9] Liu Li, Wang Jianguo. Preparation and application of acetyl tributyl citrate. Plasticizers. 2003, (2): 29-35.

You may like