Epichlorohydrin cationic

Cationic monomers are used to enhance adsorption on waste soHds and faciHtate flocculation (31). One of the first used in water treatment processes (10) is obtained by the cyclization of dimethyldiallylammonium chloride in 60—70 wt % aqueous solution (43) (see Water). Another cationic water-soluble polymer, poly(dimethylarnine-fi9-epichlorohydrin) (11), prepared by the step-growth... 

Epichlorohydrin Elastomers without AGE. Polymerization on a commercial scale is done as either a solution or slurry process at 40—130°C in an aromatic, ahphatic, or ether solvent. Typical solvents are toluene, benzene, heptane, and diethyl ether. Trialkylaluniinum-water and triaLkylaluminum—water—acetylacetone catalysts are employed. A cationic, coordination mechanism is proposed for chain propagation. The product is isolated by steam coagulation. Polymerization is done as a continuous process in which the solvent, catalyst, and monomer are fed to a back-mixed reactor. Pinal product composition of ECH—EO is determined by careful control of the unreacted, or background, monomer in the reactor. In the manufacture of copolymers, the relative reactivity ratios must be considered. The reactivity ratio of EO to ECH has been estimated to be approximately 7 (35—37). 

The chemical modification of PS with epichlorohydrin (EC), maleic anhydride (MA), acetic anhydride (AA), butadiene, and isoprene in the presence of cationic catalysis such as AICI3, FeCU, BF3 0(C2H5)2, ZnCb, TiCL, and SnCU, have been extensively studied under various conditions for the last 15 years. We have also studied their kinetics, physico-mechanical, thermal, and dielec-... 

Hercosett 125 (Hercules) reactive cationic polymer formed by condensation of adipic acid and diethylenetriamine, then partially crosslinked with epichlorohydrin... 

It has been shown for many metal halides and monomers that binary mixtures of these can be prepared (usually in a solvent) without any polymerization taking place. Such a quiescent mixture can be made to react by the addition of a suitable third compound, which is called the co-catalyst. This term is preferable to the word promoter , because in certain contexts a substance is called promoter which enhances the rate or yield of a reaction that will also go in the absence of the promoter herein lies the true distinction between promoter and co-catalyst [28]. (For example, small quantities of epoxides or epichlorohydrin act as promoters in the cationic polymerization of tetrahydrofuran.) I will take it that in the above quotation the word promoter was inadvertently used in place of co-catalyst , for only thus does it become really meaningful. 

The cationic ring-opening polymerization of epichlorohydrin in conjunction with a glycol or water as a modifier produced hydroxyl-terminated epichlorohydrin (HTE) liquid polymers (1-2). Hydroxyl-terminated polyethers of other alkylene oxides (3 4), oxetane and its derivatives (5 6), and copolymers of tetrahydrofuran (7-15) have also been reported. These hydroxyl-terminated polyethers are theoretically difunctional and used as reactive prepolymers. 

HTE liquid polymers were synthesized by cationic ring-opening polymerization of epichlorohydrin (ECH) in the presence of water or ethylene glycol (EG) as a modifier (1). Cyclic oligomers were removed by extraction. After extraction, the liquid polymers were essentially free from cyclic oligomers as determined by gel permeation chromatography (GPC) (Figure 1). 

For another example of the strong dnality in the chemical behavior of distonic cation-radicals, see Moraes and Eberlin (1998). In the gaseons phase, m- and /7-dehydrobenzoyl cation-radicals ( CgH4C =0) react selectively either as free radicals or as acylium ions, depending on the choice of the reacting partner. Transacetalization with 2-methyl-l,3-dioxolane, ketalization with 2-methoxy-ethanol and epoxide ring expansion with epichlorohydrin demonstrate their acylium reactivity. 

Polyethers are prepared by the ring opening polymerization of three, four, five, seven, and higher member cyclic ethers. Polyalkylene oxides from ethylene or propylene oxide and from epichlorohydrin are the most common commercial materials. They seem to be the most reactive alkylene oxides and can be polymerized by cationic, anionic, and coordinated nucleophilic mechanisms. For example, ethylene oxide is polymerized by an alkaline catalyst to generate a living polymer in Figure 1.1. Upon addition of a second alkylene oxide monomer, it is possible to produce a block copolymer (Fig. 1.2). 

Several dyes have been found to sensitize the cationic polymerization of cyclohexene oxide, epichlorohydrin, and 2-chloroethyl vinyl ether initiated by diaryliodonium salts (109,110). Acridinium dyes such as acridine orange and acridine yellow were found to be effective sensitizers. One example of a benzothiazolium dye (setoflavin T) was also reported, but no other class of dye nor any other example of a dye absorbing at longer wavelengths were discovered. Crivello and Lam favored a sensitization mechanism in which direct energy transfer from the dye to the diaryliodonium salt occurred. Pappas (12,106) provided evidence that both energy transfer and electron transfer sensitization were feasible in this system. 

Polyamine/EPIDMA (epichlorohydrin-dimethylamine) Cationic coagulants, usually supplied as solution liquids of 50% activity or emulsions of 40%. They have 100% charge and MW in the 100,000 to... 

Bates noted that cationic sites in the resins are formed by conversion of the secondary amine groups to quaternary nitrogen by alkylation with the epichlorohydrin. On addition of the resin to a fiber slurry, ion exchange reactions occur that bind the resin firmly to the fiber through surface carboxyl groups. However, his work indicated that the resin... 

Cationic polymerization of the unsubstituted oxirane (ethylene oxide) leads to the mixture of relatively low molecular weight (M < 103) linear polymer and up to >90% of cyclic oligomers, predominantly cyclic dimer (1,4-dioxane) 191,102]. The same behavior was observed for polymerization of substituted oxiranes, propylene oxide [103], epichlorohydrin [104], and other oxiranes having one or more substituents in the ring, although the distribution of cyclic fraction varied, depending on the structure of monomer. 

HERCOSETT 1 25 is a cationic, fiber-reactive, aqueous solution of a polyamide-epichlorohydrin resin. It is used by the textile industry for preventing felting shrinkage of wool, improving abrasion resistance of natural fibers, and as an antistat for synthetic fibers. 

In principle, the knowledge of the momentary concentrations of the active species is not necessary to determine the rate constants (cf. Fig. 14) because both kp and kj can be simultaneously determined by solving equations describing the non-stationary kinetics, as was shown for the cationic polymerization of sts rene by Peppra (partial solution) and for the polymerization of a-epichlorohydrin (complete kinetic solution). 

There have been some extensive studies of the cationic polymerization of EO [1] and of epichlorohydrin (ECH) [26]. Neither of these efforts has resulted in a clear kinetic picture. The reason seems to be that a very complex series of reactions occurs and a sensible kinetic analysis just has not emerged. 

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