Ester cellulose phosphate esters

Phosphorus-Containing Cellulose Esters. Cellulose phosphate [9015-14-9] esters (CP) are of interest because of their inherent dame resistance and ion-exchange capabiUty. 

Cellulose phosphate esters are produced from reaction with phosphoric acid and urea. The products are used to treat hypercalciuria because of its ability to bind calcium. It has also been used for the treatment of kidney stones. 

Suspension of water soluble solids in oil can be achieved by a variety of chemical additives. Chemical suspension additives that have been suggested include alkyl mercaptophosphonic acids(174), organophylic clay plus hydroxypropyl cellulose(175), polyols(176), aluminum stearate(177), organophylic clay plus surfactant(178-181), aluminum phosphate esters(182), and acrylate copolymers(183-184). 

The enzyme was purified from Candida utilis in 1965 by Rosen et al. (8Q). Dried yeast was allowed to autolyze in phosphate buffer at pH 7.5 for 48 hr, and the enzyme was isolated in crystalline form from these autolysates by a procedure which included heating to 55° at pH 5.0, fractionation with ammonium sulfate, and purification on phospho-cellulose columns from which the enzyme was specifically eluted with malonate buffer containing 2.0 mM FDP. Crystallization was carried out by addition of ammonium sulfate in the presence of mM magnesium chloride. The Candida enzyme was more active than the mammalian FDPases at room temperature and pH 9.5 the crystalline protein catalyzed the hydrolysis of 83 /nnoles of FDP per minute per milligram of protein. The enzyme was completely inactive with other phosphate esters, including sedoheptulose diphosphate, ribulose diphosphate, and fructose 1- or fructose 6-phosphates. Nor was the activity of the enzyme inhibited by any of these compounds. Optimum activity was observed at concentrations of FDP between 0.05 and 0.5 mM higher concentrations of FDP (5 mM) were inhibitory. 

Phosphate esters (alkyl or aryl, or mixed) of phosphoric acid constitute an important family of organophosphorus flame retardants.25 Triethylphosphate, a colorless liquid boiling between 209°C and 218°C, and containing 17 wt % phosphorus, has been used commercially as an additive for polyester resins/laminates and in cellulosics. In polyester resins, it functions as a viscosity depressant as well as a flame retardant. Trioctylphosphate is employed as a speciality flame-retardant plasticizer for vinyl composites where low temperature flexibility is critical. It can be also included in blends, along with general purpose plasticizers, such as phthalate esters, to improve low temperature flexibility. 

Phosphorus Phosphate esters and others (halogenated and nonhalogenated) Polyurethane foams, polyesters, and thermoplastics such as flexible PVC, modified PPO, and cellulosics Also polyethylene, polypropylene, polystyrene, and ethylene/propylene copolymers Akzo Nobel, Albemarle, Amfine Chemical Corp., Amspec Chemical, Bayer, Ciba Specialty Chemical-Melapur, Clariant, Cytec, Daihachi Chemical Industry, Great Lakes, Italmatch Chemicals, Nitroil, Rhodia... 

Considerable interest has been directed to the preparation of cellulose phosphates because of their flame retarding properties and potential use in textiles. Phosphorylation can be accomplished in several ways, e.g., by heating cellulose at high temperatures with molten urea and phosphoric acid. Other phosphor-containing esters of cellulose include phosphites, phosphinates, and phosphonites. In addition, boric acid esters have been prepared. 

When immobilized in a polymer-plasticizer matrix, (dppe)Pt S2C2(2-py) (CH2CH2OH), can be used for the rapid selective detection of volatile fluoro-, chloro-, and cyanophosphates (Table III, Fig. 10). As with many film immobilized lumiphores, the reactivity is controlled by the immobilizing matrix (39-44, 46, 50-52, 57, 58, 63, 75-77) Such an effect is seen as the sensitivity to phosphate esters increases as plasticizer (triethyl citrate, TEC) concentration increases in the cellulose acetate CA/TEC film (Table IV). 

Cellulose nitrate, glyceryl trinitrate, etbylidene diacetate, methyl methacrylate, and phosphate esters are also produced in large quantities. 

Sodium cellulose phosphate (SCP) is an insoluble, non-absorbable ester of cellulose containing 34% inorganic phosphate and 11% sodium. It is capable of binding calcium in the intestinal tract, reducing absorption of this ion, as well as magnesium. SCP is indicated only for the treatment of absorptive hypercalciuria type I with recurrent calcium oxalate or calcium phosphate nephrolitMasis. 

Plasticizers include esters of aromatic and aliphatic acids and anhydrides, epoxidized oil, phosphate esters, hydrocarbon oils and polymeric materials. PVC is the polymer most in need of plasticizers, but polyvinyl acetate, epoxies, cellulose nitrate and acetates also require these additives. 

N-(2-Hydroxypropyl) benzenesuUonamIde plastidzer, cellulose ester fire-resistance Trts p-chloroethyl) phosphate plastidzer, cellulose esters Tributyl phosphate Uniplex 225 plastidzer, cellulose ethers Galaster BL Galaster EL Galaster ML plastidzer, cellulose film... 

A lot of plasticizers typically with two ester groups have been described in the literature [39] including aliphatic diesters of phthalic acid, like diethyl phthalate, and diesters of aliphatic dicarboxylic acids like dibutyl adipate or azelate [22] as well as glycerol triacetate (triacetin), citrate esters, and phosphates [39]. Although these kind of plasticizers work well for decades in various applications, the accelerated retention test shows [39] that exudation and volatilization must be taken into account and can cause changes in the material performance. Thus, attempts have been made to synthesize long-chain esters of cellulose (LCCEs) with acid chain lengths of up to 20 carbon atoms (see [21] and references cited therein), which could be processed without external plasticizers. Positive results are reported for cellulose acetate hexanoate and cellulose acetate nonanoate [21] but these esters did not go into production. 

Starches are modified chemically in various ways. Some acetate and phosphate esters are produced commercially, as well as hydroxyalkyl and tertiary aminoalkyl ethers. Both unmodified and modified starches are used principally in paper making, paper coating, paper adhesives, textile sizes, and as food thickeners. There are many reports in the literature on graft copolymers of starch. The work is often conducted is search of biodegradable materials for packaging and agricultural mulches. Most chemical modifications of starch parallel those of cellulose. 

Cellulose esters (cellulose acetate, cellulose acetobutyrate) can be formulated with halogenated phosphoric esters (such as tris(j -chloroethyl) phosphate) as plasticizer-like flame-retardants. 

Eighty to eighty-five percent of all plasticizers are used to produce plasticized PVC. The phthalates preferentially used to plasticize PVC also act as plasticizers with certain polyurethanes, polyester resins, and phenolic resins. Phosphate esters are good plasticizers for poly(vinyl acetate), poly(vinyl butyral), cellulose acetate, and phenolic resins. Sulfonamides are special plasticizers for melamine resins, unsaturated polyesters, phenolic resins, polyamides, and cellulose acetate. A total of about 500 different plasticizers are commercially available on the market. 

Cellulose nitrate is probably the oldest cellulose ester of commercial importance. Cellulose carbonate, cellulose sulphate, cellulose nitrite and cellulose phosphate have all been synthesized and characterized but only cellulose phos jiate shows commercial promise. 

Important categories are the phosphate esters, extensively used in flexible PVC, modified polyphenylene oxide and some cellulosic polymers and chlorinated phosphates, commonly used in polyurethane formulations. 

Flammability is also a function of the plasticizer used. When phthalates are added to PVC, they reduce the total chlorine content, which reduces flame retardance. On the other hand, when organic phosphate esters are used as plasticizers, they actually increase flame-retardance (Sec. 5.7). This makes them particularly important in cellulosic plastics. 

Most plasticizers are used with polyvinyl chloride (PVC). Some go into such plastics as cellulosics, nylon, polyolefins, and styrenics. Plasticizers are typically di- and tri-esters of aromatic or aliphatic acids and anhydrides. Epoxidized oil, phosphate esters, hydrocarbon oils, and some other materials also function as plasticizers. In some cases, it is difficult to discern whether a particular polymer additive functions as a plasticizer, lubricant, or flame retardant. The most popular plasticizers are the phthalates, followed by the epoxies, adipates, azelates, trimeflitates, phosphates, polyesters, and others. There are a number of discrete chemical compounds within each of these categories. As a result, the total number of plasticizers available is substantial. 

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