Citric acid is an important organic acid, also known as citric acid, colorless crystal, often containing one molecule of water of crystallization, odorless, strong acidity, and soluble in water. Its calcium salt is easily dissolved in cold water than hot water, and this property is commonly used to identify and separate citric acid. Anhydrous citric acid can be obtained by controlling a suitable temperature during crystallization. It has many uses in industry, food industry, and cosmetics industry.
1. Physical properties at room temperature, citric acid as colorless crystals or white translucent particles or white crystalline powder, odorless, very sour taste, astringency, weakly corrosive, strongly deliquescent, water of crystallization accompanied The compound is formed and is slightly deliquescent in moist air. It may exist in the form of an anhydrate or a monohydrate: when citric acid is crystallized from hot water, an anhydrate is formed; when crystallized in cold water, a monohydrate is formed. Upon heating to 78 ° C, the monohydrate will decompose to give an anhydrate. At 15 degrees Celsius, citric acid can also be dissolved in absolute ethanol. The crystal form of citric acid varies depending on the crystallization conditions. There are anhydrous citric acid C6H8O7 and citric acid 2C6H8O7.H2O, C6H8O7.H2O or C6H8O7.2H2O containing crystal water. 2. Structurally citric acid is a tricarboxylic acid compound and thus has similar physical and chemical properties to other carboxylic acids. When heated to 175 °C it will decompose to produce carbon dioxide and water, leaving some white crystals. Citric acid is a strong organic acid. There are 3 H+s that can be ionized. Heating can be decomposed into various products and react with acids, bases and glycerol.
Index
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Index Item
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Index requirements
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Appearance
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White crystal powder
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Odor
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Tasteless
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PH value
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——
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Water content
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0.5-9.0%
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Sulfuric acid ash
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≤0.05%
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Oxalate
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≤0.01%
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Chloride
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≤0.005%
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Iron
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≤5.0ppm
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Arsenic
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≤1.0ppm
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Lead
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≤.05ppm
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Uses
for the chemical and textile
citrate technically chemical reagent for chemical analysis, used as experimental reagents, chromatography reagents and biochemical reagents; as a complexing agent, a masking agent; for the preparation of a buffer solution. The use of citric acid or citrate as a builder can improve the performance of the washing product, can quickly precipitate metal ions, prevent the re-attachment of contaminants on the fabric, maintain the necessary alkalinity for washing, and disperse and suspend the dirt and ash; Improves the performance of surfactants, is an excellent chelating agent; can be used as an acid-resistant reagent for testing architectural ceramic tiles.
Formaldehyde pollution of clothing has become a very sensitive problem. Citric acid and modified citric acid can be made into a formaldehyde-free anti-wrinkle finishing agent for anti-wrinkle finishing of cotton fabrics. Not only is the anti-wrinkle effect good, but the cost is low.
For environmental protection
Citric acid - sodium citrate buffer for flue gas desulfurization. Citric acid-sodium citrate buffer solution is a highly developed desulfurization absorbent because of its low vapor pressure, non-toxicity, stable chemical properties and high absorption rate.
For poultry production
Adding citric acid to piglet feed can early weaning, increase feed utilization by 5% to 10%, and increase sow litter size. Adding 1% to 2% citric acid to the growing and finishing pig diet can increase daily gain, reduce feed to meat ratio, increase protein digestibility, reduce back fat thickness, and improve meat quality and carcass characteristics. Rare earth citrate is a new type of high-efficiency feed additive suitable for pigs, chickens, fish, shrimps, cattle, sheep, rabbits, silkworms and other animals. It promotes animal growth, improves product quality, improves disease resistance and survival rate, and improves Feed conversion rate, shortening the feeding cycle and so on.
For sterilization, the combination of
citric acid and 80 °C temperature has a good effect of killing bacterial spores, and can effectively kill contaminated bacterial spores in the hemodialysis machine pipeline. Lemon, which enjoys the reputation of “king of western food”, has a strong bactericidal effect and is good for food hygiene. Coupled with the fragrant smell of lemon, people have always liked to use it to make cold dishes, which is not only delicious but also appetizing.
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