Acrylamide monomer

HPLC using the reverse phase mode, has heen used to determine acrylamide mononer and related compounds, including methacrylonitrile in polyacrylamide. Water soluble compounds such as acrylamide and methacrylamide have sufficient lipophilic character that they can be retained and separated on HPLC reverse-phase columns using water as the eluent. By employing a low wavelength UV detector, these compounds can be measured with high sensitivity. The relative precision of the 95% confidence level for acrylamide is 7.5%. 

In this procedure the polymer is extracted for 4 hours with methanol/water (80 + 20) and the extract injected on to a Partisil-10 OD-2, 4 x 250 mm reverse phase column. These extracts can also be examined by ion exclusion liquid chromatography [40]. 

Winkler and co-workers [41] determined free primary amines in polymeric amine hardness by reversed phase liquid chromatography. 

Mukoyama and Mori [42] investigated the elution behaviour of alkylbenzenes, phthalate esters, oligostyrenes and prepolymers of epoxy resins and methylated melamine-formaldehyde resins on a column packed with hydrophilic poly-6-hydroxy-ethyl-methacrylate. 

Griddle [43] has described a column chromatographic procedure for the identification and semi-quantitative determination of plasticisers in PVC. In this procedure the plasticiser is first Soxhlet extracted from 1 to 2 gram of PVC sample using anhydrous diethyl ether. Ether is then evaporated from the extract and residual traces of PVC precipitated by the addition of 2 ml of absolute ethanol. Following filtration of any polymer, the ethanol is finally evaporated off to provide a PVC free plasticiser extract. 

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Table 1. Physical Properties of Solid Acrylamide Monomer ...

The reaction with sodium sulfite or bisulfite (5,11) to yield sodium-P-sulfopropionamide [19298-89-6] (C3H7N04S-Na) is very useful since it can be used as a scavenger for acrylamide monomer. The reaction proceeds very rapidly even at room temperature, and the product has low toxicity. Reactions with phosphines and phosphine oxides have been studied (12), and the products are potentially useful because of thek fire retardant properties. Reactions with sulfide and dithiocarbamates proceed readily but have no appHcations (5). However, the reaction with mercaptide ions has been used for analytical purposes (13)). Water reacts with the amide group (5) to form hydrolysis products, and other hydroxy compounds, such as alcohols and phenols, react readily to form ether compounds. Primary aUphatic alcohols are the most reactive and the reactions are compHcated by partial hydrolysis of the amide groups by any water present. 

Mitsui Toatsu Chemical, Inc. disclosed a similar process usiag Raney copper (74) shortiy after the discovery at Dow, and BASF came out with a variation of the copper catalyst ia 1974 (75). Siace 1971 several hundred patents have shown modifications and improvements to this technology, both homogeneous and heterogeneous, and reviews of these processes have been pubHshed (76). Nalco Chemical Company has patented a process based essentially on Raney copper catalyst (77) ia both slurry and fixed-bed reactors and produces acrylamide monomer mainly for internal uses. Other producers ia Europe, besides Dow and American Cyanamid, iaclude AUied CoUoids and Stockhausen, who are beheved to use processes similar to the Raney copper technology of Mitsui Toatsu, and all have captive uses. Acrylamide is also produced ia large quantities ia Japan. Mitsui Toatsu and Mitsubishi are the largest producers, and both are beheved to use Raney copper catalysts ia a fixed bed reactor and to sell iato the merchant market. 

Contact with aciylamide can be hazardous and should be avoided. The most serious toxicological effect of exposure to acrylamide monomer is as a... 

Estimated production capacity for the Japanese producers is 77,000 t/yr for the American producers, about 70,000 t/yr and for the European producers about 50,000 t/yr (104). The Hst prices for the monomer have increased dramatically over the past 15 years, according to the ChemicalM.arketing Reporter (105). In 1975 the price for 50% solution was 0.903/kg, compared to 1.68/kg in December 1990 (100% basis, FOB plant). The sohd crystalline monomer always demands a premium price because of the added cost of production, and sold in December 1990 for 2.27/kg compared to 1.09/kg in 1975. There are at least 35 supphers of acrylamide monomer most of them obviously are repackagers. 

Manufacturing processes have been improved by use of on-line computer control and statistical process control leading to more uniform final products. Production methods now include inverse (water-in-oil) suspension polymerization, inverse emulsion polymerization, and continuous aqueous solution polymerization on moving belts. Conventional azo, peroxy, redox, and gamma-ray initiators are used in batch and continuous processes. Recent patents describe processes for preparing transparent and stable microlatexes by inverse microemulsion polymerization. New methods have also been described for reducing residual acrylamide monomer in finished products. 

The water content of a hydrogel depends on the hydrophilicity of the monomer, eg, cured poly(HEMA) absorbs 60% of its weight of water and thus forms a hydrogel with about 38% water content. Other hydrophilic monomers, such as A/-vinylpyrrohdinone [88-12-0] (NVP) (6), and glycerol methacrylate [100-92-5] (GM) (7), and acrylamide monomers, such as diacetone acrylamide [2873-94-9] (DAA), have also been used to form hydrogels with higher water content. 

The involvement of acrylamide monomer in the initiation step is also observed in the pentamine-aqua-co-balt(III) complex [47]. 

Righetti and CagUo [315] have also found that Bis reacts faster than acrylamide and that this leads to the formation of nonhomogeneous regions in the gel. At the critical gel point they found 50% of the acrylamide monomer and 80% of the Bis monomer had reacted. The reaction was found to continue beyond the gel point, with an eventual 99%... 

A polyacrylamide with a molecular mass of 1.87 x 105 was prepared by polymerising a 5% w/v aqueous solution of acrylamide monomer in the presence of 0.15% w/w benzyl alcohol and 0.025% w/w potassium persulphate for 45 minutes at 80 °C. This product was effective in preventing the bleeding of direct dyes and hydrolysed reactive dyes from dyed cotton, which was simply dipped in a 1% solution of the polyacrylamide and dried in air [450]. 

Betso SR, McLean JD. 1976. Determination of acrylamide monomer by differential pulse polarography. Anal Chem 48 766-770. 

The standard gel-forming reaction is shown in Figure 8.2. Acrylamide and the cross-linker N, A-methylenebisacrylamide (bis) are mixed in aqueous solution and then copolymerized by means of a vinyl addition reaction initiated by free radicals.1317 Gel formation occurs as acrylamide monomer polymerizes into long chains cross-linked by bis molecules. The resultant interconnected meshwork of fiberlike structures has both solid and liquid components. It can be thought of as a mass of relatively rigid fibers that create a network of open spaces (the pores) all immersed in liquid (the buffer). The liquid in a gel maintains the gel s three-dimensional shape. Without the liquid, the gel would dry to a thin film. At the same time, the gel fibers retain the liquid and prevent it from flowing away. 

Acrylamide monomer N, N1-methylene-bls-acrylamide cross-linker, bis ... 

It took more than 20 years for manufacturers to devise production and distribution networks for delivering consistently high-quality gels to customers. The problems that the companies faced stem from the limited shelf life of polyacrylamide gels. Because polyacrylamide gels hydrolyze over time as shown in Figure 8.2, they are inherently unstable. At basic pH, the pendant, neutral carboxamide groups (-CO-NH of the acrylamide monomers hydrolyze to ionized carboxyl... 

Synonyms AAM Acrylamide monomer Acrylic acid amide Acrylic amide AI3-04119 Amresco acryl-40 BRN 0605349 CCRiS 7 EiNECS 201473-7 Ethylene carboxamide NSC 7785 Optimum Propenamide 2-Propenamide Propenoic acid amide RCRA waste number U007 UN 2074 Vinyl amide. 

Brown. L.. Bancroft. K.C.C., and Rhead, M.M. Laboratory studies on the adsorption of acrylamide monomer by sludge, sediments, clays, peat and S3mthetic resins. Water Res., 14(7) 779-781, 1980. 

Brown, L. and Rhead, M. Liquid chromatographic determination of acrylamide monomer in natural and polluted aqueous environments. Analyst, 104(1238) 391-399,1979. 

Lead bromide is used for developing images in photography as inorganic filler in fire-retardant plastics as a photopolymerization catalyst for acrylamide monomer and as a welding flux for welding aluminum or its alloys to other metals. 

Impurities in water treatment chemicals halogenated hydrocarbons in chlorine, oxides of nitrogen from ozonators, chlorates and chlorites from chlorine dioxide, acrylamide monomers. 

The physical properties of solid acrylamide monomer are summarized in Table 1. Typical physical properties of 50% solution in water appear in... 

TABLE 1. PHYSICAL PROPERTIES OF SOLID ACRYLAMIDE MONOMER... 

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