Views: 0 Author: Site Editor Publish Time: 2023-09-15 Origin: Site
Sodium citrate, also known as trisodium citrate, is an organic acid sodium salt. Appearance: white to colorless crystals, with a cool salty smell and stable in the air. The chemical formula is C6H5Na3O7, soluble in water and insoluble in ethanol. The aqueous solution is slightly alkaline and is often used as a buffer, complexing agent, and bacterial culture medium. It is used in medicine as a diuretic, expectorant, anticoagulant, and used in food, beverages, electroplating, photography, etc. It is one of the basic agents in biological experiments.
Sodium citrate is the most important citrate. It is mainly produced by fermenting starch substances to produce citric acid, which is then neutralized with alkaline substances. Its biochemical properties are as follows.
1. Safe and nontoxic:
Since the raw materials for preparing sodium citrate are basically from grain, it is absolutely safe and reliable and will not harm human health. The Food and Agriculture of the United Nations and the World Health Organization do not set any limit on its daily intake, and it can be considered drug-free.
Sodium citrate is partially converted into citric acid after being diluted with a large amount of water in nature. Both coexist in the same system. Citric acid is easily biodegraded in water through the action of oxygen, heat, light, bacteria and microorganisms. Its decomposition pathway is generally through aconitic acid, itaconic acid, and citraconic anhydride, and then converted into carbon dioxide and water.
3. Complexing ability:
Sodium citrate has good complexing ability for metal ions such as Ca2+ and Mg2+. It also has good complexing ability for other metal ions, such as Fe2+ plasma.
4. Other properties:
Sodium citrate has excellent solubility properties, and its solubility increases as the water temperature increases. Sodium citrate has good pH adjustment and buffering properties. Sodium citrate is a weak acid and strong alkali salt. It can form a strong pH buffer with citric acid, so it is important in some situations where the pH is not suitable for large-scale changes. In addition, sodium citrate also has excellent retarding and stabilizing properties.
Sodium citrate has many of the above-mentioned excellent properties, so it has a wide range of uses.
Sodium citrate is mainly used as a food additive and has the largest demand. It can also be used as a flavoring agent, swelling agent, stabilizer, buffering agent, and emulsifier. In addition, when combined with citric acid, sodium citrate can also be used as a flavoring agent, gelling agent and nutritional supplement for various pastries, cold drinks, juices, beverages, cold drinks, dairy products and jams.
In 1914, it was discovered that sodium citrate has a long-lasting anticoagulant effect and can preserve blood for a long time. Sodium citrate also has a preservative effect and is used for long-term storage of some drugs.
3. Construction industry
In the construction industry, sodium citrate can be added as a retardant when making concrete, which can improve the frost resistance, compression resistance and tensile resistance of cement products. Under the social conditions of increasingly serious environmental problems, the sulfur dioxide in the exhaust gas of some smelting plants seriously exceeds the standard. Studies have shown that the use of sodium citrate can remove sulfides in industrial exhaust gas.
4. Electroplating and manufacturing industry
Because sodium citrate has good complexing properties, it is also used in the electroplating industry. The electroplating process has developed rapidly. Neutral citrate nickel plating has the advantages of environmental protection, pollution-free, easy maintenance, low corrosion, and excellent coating performance. Therefore, it has been used on a large scale in industrial production. In addition, sodium citrate is also used in grinding aid and whitening technology in the manufacturing of nanomaterials and ceramic industries.
5. Industrial cleaning
Due to the extensive use of sodium tripolyphosphate in the washing industry, washing wastewater contains a large amount of phosphate. The water quality is enriched with nutrients, and algae blooms quickly trigger red tides. This lack of oxygen in the water greatly harms the survival of aquatic organisms. This has become an urgent problem for environmental protection. Since the 1970s, some countries have restricted phosphorus content in detergents. Replacing sodium tripolyphosphate with sodium citrate can not only improve the decontamination effect, but also reduce environmental pollution. Studies have shown that special cleaning agents containing sodium citrate are non-corrosive, so some precision instruments can also be cleaned with this special cleaning agent. Food safety has attracted more and more people's attention. In order to remove pesticide residues, a special cleaning agent containing sodium citrate for cleaning vegetables and fruits has been developed.
With the deepening of research, the uses of sodium citrate are increasing.