Tripolyphosphate, effect solubility

Various polyphosphates are effective sequestering agents under appropriate conditions. The best known of these is sodium hexametaphosphate (10.14), the cyclic hexamer of sodium orthophosphate. Further examples are the cyclic trimer sodium trimetaphosphate (10.15), as well as the dimeric pyrophosphate (10.16), the trimeric tripolyphosphate (10.17) and other linear polyphosphates (10.18). All of these polyanions function by withdrawing the troublesome metal cation into an innocuous and water-soluble complex anion by a process of ion exchange as shown in Scheme 10.7 for sodium hexametaphosphate. Hence these compounds are sometimes referred to as ion-exchange agents. 

Table I. Effects of 17o Orthophosphate, Tripolyphosphate, and Hexametaphosphate on Calcium Solubility from Ground Beef or Soy Protein Concentrate Subjected to In Vitro Gastric and Gastrointestinal Digestions...

A-(2-Hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is a water-soluble derivative of chitosan (CS), synthesized by the reaction between glycidyl-trimethyl-ammonium chloride and CS. HTCC nanoparticles have been formed based on ionic gelation process of HTCC and sodium tripolyphosphate (TPP). Bovine serum albumin (BSA), as a model protein drug, was incorporated into the HTCC nanoparticles. HTCC nanoparticles were 110-180nm in size, and their encapsulation efficiency was up to 90%. In vitro release studies showed a burst effect, followed by a slow and continuous release. Encapsulation efficiency was obviously increased with increase in initial BSA concentration [15]. 

The use of builders in liquid laundry formulations has effectively been restricted to citrates and fatty acid soaps (in isotropic compositions sold in the U.S. and Europe). Although liquid laundry products can contain tripolyphosphate, soda ash, NTA, and other common builders found in powder laundry, limitations on solubility (in a surfactant matrix) or regulatory concerns have restricted their utilization. There is a finite number of patents covering zeolite-built HDLDs, but problems... 

Because complexation with Ca2+ results in insoluble CaCC>3, which deposits on items being washed, carbonate alone is not an effective builder system. In contrast, tripolyphosphate forms a soluble calcium salt, preventing deposition of insoluble salts. Sodium sesquicarbonate (Na2CC>3 NaHC03 -2 0) and sodium bicarbonate (NaHCCb) have not been used in LADD formulations, except where buffering action is needed. 

Because of pollution problems that can be caused by chromates, numerous inhibitor systems have been developed as alternatives— for example, organic phosphonic acids, which are effective in alkaline waters and are biodegradable [8]. Nontoxic inhibitor formulations containing mixtures of azoles and water-soluble phosphates (e.g., disodium phosphate and sodium tripolyphosphate) have been developed [9]. Sodium molybdate, which is less toxic than sodium chromate, has also been reported to be a useful component of inhibitor formulations for use in recirculating aqueous systems [9,10]. Other nontoxic, chromate-free inhibitor formulations are based on mixtures of sorbitol, benzotriazole or tolytriazole, and water-soluble phosphates [9]. 

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