Abstract
Trisodium phosphate dodecahydrate is also known as trisodium phosphate, sodium orthophosphate. It is colorless crystal. The relative density is 1.62. Melting point is 73.4℃. It is easily weathered. When heated to 100℃, it loses crystal water to from Anhydrous. The relative density is 2.537 (17.5/4℃). Melting point is 1340℃. It can dissolve in water, in aqueous solution it can almost decompose into disodium hydrogen phosphate and sodium hydroxide, aqueous solution is alkaline, it has some erosion for skin, it is not soluble in ethanol and carbon disulfide.
Trisodium phosphate dodecahydrate can be used in the textile, printing and dyeing, paper, power generation, chemical industry and it is often used as water softener and boiler cleaning agent, it is also used as metal rust agent, reactive dye fixing agent, phosphating agent of steel containers, juice purification agents, rubber latex coagulant drugs such as penicillin and train agents. Trisodium phosphate dodecahydrate can also be used as food additive, Chinese GB2760-1996 regulations allow the use of food with moisture-retaining agent. It can also be used as development accelerators, it is commonly used in the oil-soluble color developing solution.
The chemical properties, uses and synthetic methods of trisodium phosphate dodecahydrate are edited by Chemicalbook.(2016-12-04)
Chemical properties
It’s the colorless or white crystals and can be dissolved in water and aqueous solution of it is strongly alkaline. It is insoluble in ethanol and carbon disulfide.
Uses
(1) It can be used as the water softener, detergent, boiler detergents, metal rust inhibitors, dyeing fixing agent, fluxing agent for enamel production, bleaching agent, leather degreaser agent and degumming agent etc.
(2) It can be used as analytical reagents, water softener and metal cleaning agent.
(3) It can be used as water softener, boiler cleaning agents and metal rust inhibitors. It can also be applied to paper, leather, photography and so on.
(4) It can be used as the softener, detergent, boiler scale inhibitor, water softener for paper dyeing water softener, PH buffers of the adhesive for producing glossy paper, the fixing agent for textile printing, mercerized enhancer for fabric, tendering resistant agent for making thread in the chemical, textile printing paper dyeing, power generation and other industries. It can be used for chemical degreasing and decontamination, and can also be used as the metal corrosion resistance agent or rust inhibitor in metallurgical industry; fluxing agent and bleaching agent in enamel industry; degreasing agents and rawhide unglued agent in leather industry; favorable promoter for photographic developing solution; tooth cleaners and detergents for bottle; coagulating agent for rubber latex; juice purification agents.
(5) It can be used as water softener, photographic developer and detergents.
(6) Phosphate has the effect of improving quality in food processing, for example, keep the water capacity in meat and improve adhesive force in order to reduce the loss of nutrients make the meat soft. It can be used as the emulsifier, nutritional supplement and quality improver In food processing. It is the raw material of making the buck. It can also be used for refining the sugar and making theα-starch. The detergents for the bottles and cans.
Production method
(1) Neutralization method: Diluting the food-grade phosphoric acid with deionized water to a certain concentration solution, then add the mixed liquor to a stirred reactor, add the food grade caustic soda solution to the reactor slowly to neutralize the reaction. Adjust the ratio of Na/P to 3.24~3.26. Purifying the solution with bleaching agent, removing heavy metal agent and removing arsenic agent, and then remove the impurities by filtration. After the cooling crystallization, centrifugal separation and drying of the filter liquor, the final product-trisodium phosphate 12-hydrate can be obtained. The reaction is
H3PO4+3NaOH→Na3PO4+3H2O
(2) WPA method: add some wash water to the phosphoric which can be obtained by the reaction of the phosphate rock with sulfuric acid and dilute the solution which the content of the pentoxied is 18%~20% . The mixed liquor was heated to 85 ℃, adding 30 to 35. B6 sodium carbonate solution slowly at the condition of stirring and make the pH of it at the range of 8~8.4. Then, adding mother liquid of trisodium phosphate to the reactor and make the content of phosphorus pentoxide in the solution is less than 12%. After Insulated for 15~20min, the solution is filtered, concentrated and evaporated to 24~25 ° Bé. Adding the liquid caustic soda to make sodium reserve ratio to 3.24~3.26. The refined phosphate 12-hydrate can be obtained after the cooling crystallization, centrifugal separation and drying of the solution. The reaction is
Ca5F (PO4) 3 + 5H2SO4 + 10H2O → 3H3PO4 + 5CaSO4? 2H2O + HF
H3PO4 + Na2CO3 → Na2HPO4 + H2O + CO2 ↑
Na2HPO4 + NaOH →-Na3PO4 + H2O
Thermal phosphoric acid method: Adding the phosphoric acid into the reactor and neutralize the liquid caustic soda which is slowly added into the reactor under the condition of the stirring can get the trisodium phosphate. The refined phosphate 12-hydrate can be obtained after the cooling crystallization, centrifugal separation and drying of the solution. The reaction is
H3PO4+3NaOH→Na3PO4+3H2O
Identification method
The reaction of aqueous solution of trisodium phosphate (1 + 20) should include sodium salt reaction and phosphate reaction.
1. Sodium salt reaction: refer to the identification methods of sodium hydroxide.
2. Phosphate Reaction: refer to the identification methods of monocalcium phosphate.
Usage of food additives
Quality improver, emulsifier and a chelating agent.
Scope and usage: China's "food additives health standards" (GB 2760-1996) states:” Trisodium phosphate can be used for canned food, fruit juice drinks, dairy products and plant protein drinks, the maximum amount for the above terms is 0.5g/kg; for western-style ham and meat products, the maximum amount is 3.0g/kg; for cheese, the maximum amount is 5.0g/kg; for beverages, the maximum amount is 1.5g/kg.”
When using composite phosphate, China has a regulation: with the total amount of phosphate, canned food and meat products cannot exceed 1.0g/kg; condensed milk cannot exceed 0.50g/kg. Using the sodium pyrophosphate, sodium tripolyphosphate and trisodium phosphate together, with the total amount of phosphate, cannot exceed 5g/kg; smoked ham for western-style cooking cannot exceed 5g/kg; for ham cannot exceed than 8g/kg.
Toxicity
The Adl is at the range of 0～70 mg/kg(with the total amount of phosphate) and the LD50>2 g/kg(tested by the marmot orally). The sodium phosphate can be used in canned food, fruit juice drinks, dairy products and soy milk etc, the maximum amount is 0.5 g/kg.
Description
Sodium phosphate tribasic dodecahydrate is also known as trisodium phospate or TSP. It is a highly soluble in water and widely used as a cleaning agent. The pH of a 1% solution is typically around 12, making this reagent sufficiently alkaline for saponification of grease and oils. In combination with surfactants, TSP is an excellent agent for cleaning everything from laundry to concrete driveways. This versatility and low manufacturing price made TSP the basis for a plethora of cleaning products sold in the mid-20th century.
Trisodium phosphate is used in the isolation of mycobacteria, including culturing of tubercle bacilli. Has been used as a protein precipitant in certain applications and in co-precipitation and fractionization of nucleotides. May be used for the preservation of biologically active soil samples. Because of the alkaline pH, TSP disrupts cytoplasmic and outer membranes of Salmonella enterica cells making it useful in preventing the spread of bacteria.
It is used in photographic developing, clarifying sugar, removing boiler scale, softening water and manufacturing of paper. They are added to many foods as an emulsifier to prevent oil separation. It can be utilized as a leavening agent. Some instances of these foods include the batter coating on breaded fish or chicken, and commercially baked cakes. Adding this item to food increases the shelf life of the food, maintaining the texture and visual aspect of the food.
Chemical Properties
colorless or white crystal(s); used to soften water, as a detergent and metal cleaner [MER06] [HAW93] [STR93]
Uses
Sodium phosphate tribasic dodecahydrate is often used in the formulation of various buffers.
General Description
Sodium phosphate tribasic dodecahydrate is a hydrated trisodium salt of phosphoric acid. It is widely used in various water treatment methods.
Hazard
Low toxicity by ingestion.
Biochem/physiol Actions
Sodium phosphate tribasic also referred to as Trisodium phosphate or TSP is a widely used cleaning agent. Trisodium phosphate disrupts cytoplasmic as well as outer membranes of Salmonella enterica cells and hence prevents the spread of bacteria. Further, it is corrosion inhibitor for iron and inhibits the rate of the anodic iron dissolution reaction in unbuffered solutions.
Purification Methods
It crystallises from warm dilute aqueous NaOH (1mL/g) on cooling to 0o.
