Polyvinyl chloride, extraction

The addition of zinc to a solution of polyvinyl chloride extracts chlorines in a paired manner to give, for example,... 

Solutions in contact with polyvinyl chloride can become contaminated with trace amounts of lead, titanium, tin, zinc, iron, magnesium or cadmium from additives used in the manufacture and moulding of PVC. V-Phenyl-2-naphthylamine is a contaminant of solvents and biological materials that have been in contact with black rubber or neoprene (in which it is used as an antioxidant). Although it was only an artefact of the separation procedure it has been isolated as an apparent component of vitamin K preparations, extracts of plant lipids, algae, livers, butter, eye tissue and kidney tissue [Brown Chem Br 3 524 1967]. 

El-Abbes Faouzi et al. [77] studied the stability, compatibility and plasticizer extraction of miconazole injection added to infusion solutions and stored in polyvinyl chloride containers. The stability of miconazole in various diluents and in... 

ISO 2898-1 1996 Plastics - Plasticized poly(vinyl chloride) (PVC-P) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 2898-2 1997 Plastics - Plasticized poly(vinyl chloride) (PVC-P) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 3114 1977 Unplasticized polyvinyl chloride (PVC) pipes for potable water supply -Extractability of lead and tin - Test method... 

Uses Manufacture of polyvinyl chloride and copolymers adhesives for plastics refrigerant extraction solvent organic synthesis. 

The initial halogenated polymeric materials were obtained from the polyvinyl chloride-polyvinylidene chloride, PVC-PVDC (Rovil fiber) and chlorinated polyvinyl chloride, PVC. Dehydrochlorination was performed in the presence of a base solution in a polar organic solvent (dimethylsulfoxide, acetone or tetrahydro-furane). The products were filtered and extracted with water in a Soxhlet apparatus until all chloride ions were removed. Thermal treatment was performed in a tubular furnace in CO flow at 10 cm min". ... 

For similar solvent polymeric membranes (78 wt.% dicresyl butyl phosphate in polyvinyl chloride) self-diffusion coefficients of the order of 10-7 cm2s 1 have been reported.12 These diffusion coefficients, as well as measurements of rotational mobilities,14 indicate that the solvent polymeric membranes studied here are indeed liquid membranes. This liquid phase is so viscous, however, that convective flow is virtually absent. This contrasts with pure solvent membranes where an organic solvent is interposed between two aqueous solutions either by sandwiching it between two cellophane sheets or by fixing it in a hole of a Teflon sheet separating the aqueous solutions.15 The extremely high convective flow is one of the reasons why the term membrane for extraction systems... 

While not mandatory from regulatory guidehnes, much research has been carried out to investigate the extractability of plastic additives in contact with a variety of pharmaceutical formulations, mainly those for parenteral use. The research concentrates on the extractability of plasticizer phthalates, mainly di-2-ethylhexylphthalate (DEHP) from polyvinyl chloride (PVC) into the blood, blood components, and infusion solutions. The purpose for these studies lies in its, up to now, controversial hazardous effects on humans. The amount of additive necessary to turn rigid PVC into a flexible material (40% m/m) and the absence of chemical bonds between the polymer and the plasticizer make it a potentially extractable species. 

Faouzi, M. A., Khalfi, F., Dine,T.,Luyckx, M., Brunet, C., Gressier, B., Goudaliez,F., Cazin, M., Kablan, J., Belabed, A., and Cazin, J. C. (1999), Stability, compatibility and plasticizer extraction of quinine injection added to infusion solutions and stored in polyvinyl chloride (PVC) containers,/ Pharm. Biomed. Anal., 21, 923-930. 

Allwood, M. C, and Martin, H. (1996),The extraction of diethylhexylphthalate (DEHP) from polyvinyl chloride components of intravenous infusion containers and administration sets by paclitaxel injection, Int. J. Pharm., 127, 65-71. 

Adipic acid can also polymerize with alcohols such as ethylene glycol to form polyesters, which can combine with isocyanates to form polyurethanes. Smaller esters of adipic acid produced with alcohols in the C-8 to C-10 range are called adipates. These are used as softeners in plastic (such as polyvinyl chloride) and as synthetic grease base oils. Adipic acid is also used in the food industry. Food grade adipic acid is prepared synthetically or extracted from beet juice as a natural source. It is used as a gelling agent, as an acidulant to provide tartness, and as a preservative. 

Now the lone chlorine atom has found itself isolated since the zinc only extracts two adjacent chlorines. Such a result is called reactant isolation, and one wishes to predict the chlorine concentration left in the polymer as a function of time. It was shown by Flory76 that the fraction of chlorines unreacted should approach e 2, and this was used in fact by Marvel77 to determine the structure of polyvinyl chloride. Other examples are the condensation of the polymer of methyl vinyl ketone76 and the vulcanization of natural rubber.78 The vulcanization studies supply another example where a molecular structure was determined by a kinetic scheme. The complete time dependence of the process was recently derived by Cohen and Reiss24 using a novel method of multiplets, which will now be outlined. 

Carboxylic acids often have been identified by means of paper chromatography Clarke and Bazill (10) have extracted plasticizers from polyvinyl chloride first with ether and then with methanol. Subsequently the extracts were saponified with alcoholic potassium hydroxide, and the precipitated potassium salts were isolated and converted into free acids. These, in alcoholic solution, were then applied to paper and chromatographed ascendingly with a mixture of butanol, pyridine, water, and ammonia the migration period was about six hours. A number of additional color tests facilitated identification of unknown acids. 

ECD = electron capture detector FID = flame ionization detector GC = gas chromatography HRGC = high resolution gas chromatography LC-APCI-MS = liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry LSE = liquid-solid extraction MS = mass spectrometry PVC = polyvinyl chloride SFE = supercritical fluid extraction... 

Fig. 1. Chromatograms, using both FID and ECD, of an extract of a blood sample from a patient taking flurazepam who had a blood transfusion. A, di(2-ethylhexyl) phthalate from the polyvinyl chloride transfusion bag B, VLdesalkylflurazepam ...

Increases in properties are often associated with the extraction of components from the glove material by the pesticide formulation. The stiffening of polyvinyl chloride (PVC) gloves due to extraction of plasticizer is an examjie. 

However, a 2% v/v aqueous solution in a polyethylene container, stored at 20°C, may lose up to 15% of its benzyl alcohol content in 13 weeks. Losses to polyvinyl chloride and polypropylene containers under similar conditions are usually negligible. Benzyl alcohol can damage polystyrene syringes by extracting some soluble components. ... 

Plastic pipes are polymeric in nature (e.g., polyvinyl chloride). Within the pipe are traces of the monomers used in the manufacture of the pipe (e.g., vinyl chloride). In addition, there are a variety of other chemicals added during the manufacture of the pipe as lubricants to facilitate their manufacture or stabilizers to prevent the breakdown of the pipe. In Europe, lead has been used as the stabilizer for pipes, whereas various organic tin compounds have been utilized in the United States. Lead is widely recognized as being toxic. Inorganic tin has a very limited toxicity, but this is not the form of tin that is used. Some of the organic tin compounds are potent nervous system toxins (e.g., trimethyl or triethyl tin), while others appear to adversely affect the immune system (dioctyl tin). The forms of tin used in polyvinyl chloride pipe, however, are primarily monomethyl and dimethyl tin, which are much less active as neurotoxins than the trimethyl tin. There will be some extraction of all these chemicals from the pipe when it is first put into service. However, the concentrations that are found in the water decrease sharply with continued use of the pipe. This is only partially due to the depletion of the chemical from the pipe because continuous water flow will form an impermeable barrier (e.g., calcium carbonate) on the interior of the pipe that minimizes leaching from its surface. 

FIGURE 10.9 Flowsheet for the Haifa (Israel Mining Industries) hydrochloric acid acidula-tion route to phosphoric acid. Digestion for a short time is followed by solvent extraction in polyvinyl-chloride mixer settlers, which tolerate the corrosive conditions. (Reprinted from Chemical Engineering (NX) [64] by special permission from the journal and McGrawHill Inc.)... 

Chlorine is used to produce many commercially important products. Tremendous amounts of it are used in extractive metallurgy and in chlorinating hydrocarbons to produce a variety of compounds (such as polyvinyl chloride, a plastic). Chlorine is present as CI2, NaClO, Ca(C10)2, or Ca(C10)Cl in household bleaches as well as in bleaches for wood pulp and textiles. Under carefully controlled conditions, CI2 is used to kill bacteria in public water supplies. 

The plastics industry and all the products made from plastics are almost entirely dependent on chemicals extracted or produced from hydrocarbons. This includes not only the familiar materials such as polyethylene, polypropylene, polyvinyl chloride (PVC), epoxies, nylon, polyesters, polycarbonate. Teflon and Plexiglas, but also includes a large portion of materials made from rubber and a diverse group of other materials formulated from polymers such as tape, glue, ink, waterproofing, wax, and polishes. Virtually all the synthetic fibers used in textile products, Orion , Dacron , Nylon and polyesters are made from polymers based on hydrocarbons. 

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