Epichlorohydrin, epoxy resins from

Enzyme-substrate complex, 1041 Ephedrine, structure of, 65 Epibatidine, molecular model of. 332 Epichlorohydrin, epoxy resins from, 673-674 Epimer, 303... 

It is possible to explain the formation of epoxy resins from bisphenol A and epichlorohydrin according to the following scheme. 

Preparation of Epoxy Resins from Bisphenol A and Epichlorohydrin... 

FIGURE 2.4 Synthesis of DGEBA epoxy resin from bisphenol A and epichlorohydrin/... 

Storage Store in cool, dry place away from ignition sources keep tightly closed Uses Chem. intermediate in mfg. of pharmaceuticals, diuretics, barbiturates, hypnotics, varnishes, polymers, epichlorohydrin, epoxy resins, adhesives, plastics, glyceryol, insecticides synthesis of allyl compds. alkylating agent formerly as chem. intermediate for allyl starch Regulatory HAP SARA 313 reportable Calif. 

Epoxy phenolic adhesives are polyepoxy compounds which possess epoxy reactivity and phenolic resin heat resistance. These are prepared by condensing epichlorohydrin and novolac phenolics (phenol/formaldehyde ratio > 1). A recent Japanese patent issued to Mitsubishi Petrochemical Co. describes the preparation of epoxy resins from epichlorohydrin condensation with phenolic resins prepared from phenol and substituted aldehydes, e.g., vanillin. These resins (23) have high epoxy contents (epoxy equivalent weights >200) and relatively high softening points (85-95°C). 

In 1936, Pierre Castan of DeTrey Freres Co. produced a low melting epoxy resin from bisphenol A and epichlorohydrin that gave a thermoset composition with phthalic anhydride. Application of the hardened composition was foreseen in dental products, but initial attempts to market the resin were imsuccessfiil. The patents were licensed to Ciba AG of Basel, Switzerland, and in 1946 the first epoxy adhesive was shown at the Swiss Industries Fair, and samples of casting resin were offered to the electrical industry. 

Figure 7.15 Synthesis of epoxy resins from bisphenols and epichlorohydrin (ECH).

A numerical simulation was developed to predict the one-dimensional transient temperature profile of the composite during both microwave and conventional heating for a glass/epoxy laminate with a thickness of 25 mm. As raw materials for the experimental investigation a bisphenol F/epichlorohydrin epoxy resin (Shell Epon 862) and an aromatic diamine (Shell Epi-Cure W) as a curing agent were used. The microwave power was varied continuously from 0 to 6 kW... 

Epoxy Resins. The chemistry of epoxy resin adhesives is quite varied. However, the most widely used is that formed from the reaction of 4,4 -isopropyhdene diphenol (bisphenol A) [80-05-7] and epichlorohydrin [106-89-8] C H CIO. This epoxy resin is more commonly known as... 

Epoxy Resins. Epoxy resins (qv) or polyether resins are thermosets used as the binder for terrazzo dooring. The epoxy resin often is made from epichlorohydrin and bisphenol A. An excess of epichlorohydrin is used to assure that the intermediate product contains terminal epoxide groups. 

Epoxy resins are widely used in high-strength adhesives, corrosion-resistant coatings, and corrosion-resistant pipes and tanks. The simplest starting material for these thermoset polymers is made from phenol, acetone (to bisphenol A), and epichlorohydrin. 

The epoxy polymers are basically poly ethers. One type of epoxy polymer (or epoxy resins) are prepared from epichlorohydrin and bisphenol-A. The reaction is carried out with excess of epichlorohydrin. The various reactions for the preparation of an epoxy polymer are given in the following discussion. 

Epoxy resins are really polyethers but are named epoxies because of the presence of epoxide groups in the starting material. They were initially synthesized from epichlorohydrin and bisphenol A in the 1940s. General properties are listed in Table 4.9. 

The DP is dependent on the ratio of reactants. Generally an excess of the epichlorohydrin is used to produce cyclic ether end groups. Epoxies are formed from the reaction of diamines with low molecular weight epoxy resins that retain their cyclic ether end groups. Figure 4.9 shows the formation of this process. These materials are often sold as two-part, or two-pot, epoxy adhesives. Most use-at-home epoxy packages contain a part A of epoxy resin and a part B of hardener (typically a diamine). These two are mixed as directed and applied. They dry fast, so they can be handled in 5 10 min. Full strength occurs after 5 7 days. 

The commercially most important epoxy resins are those prepared from 4,4 -isopropylidenediphenol (bisphenol A) and epichlorohydrin. They have molecular weights between 450 and 4000 [n in formula (II) between 1 and 12] and softening points between 30 and 155 °C. Such epoxy resins are still soluble, but become insoluble and infusible through subsequent crosslinking reactions. 

Epoxy Resins or Epoxies. The commercially available materials of this glass are usually derived from epichlorohydrin and bis phenol A (See under Epon Resins). Before curing they are viscous liquids or clear, brittle solids... 

Allyl chloride is used to make intermediates for downstream derivatives such as resins and polymers. Approximately 90% of allyl chloride production is used to synthesize epichlorohydrin, which is used as a basic building block for epoxy resins and in glycerol synthesis. Allyl chloride is also a starting material for allyl ethers of phenols, bisphenol A and phenolic resins, and for some allyl esters. Other compounds made from allyl chloride are quaternary amines used in chelating agents and quaternary ammonium salts, which are used in water clarification and sewage sludge flocculation (Kneupper Saathoff, 1993). 

Epoxy resins were first introduced by Ciba-Geigy, Ltd., in 1946 although their development began decades earlier. The most common commercial epoxy resin is formed from the reaction of bisphenol A and epichlorohydrin. This resin is known as the diglycidyl ether of bisphenol A or DGEBA (Fig. 2.4). 

Glycidyl ethers of aliphatic polyols based on polyglycol, glycerin, and other polyols are flexible epoxy resins. They are used as reactive diluents and flexibihzers for solvent-free epoxy resin formulations. Epoxy-polyglycol resins that are produced from the reaction of epichlorohydrin and polyester polyols based on ethylene or propylene oxide are the most common of these types of flexible epoxy resins. Examples of typical commercial aliphatic epoxy resins are shown in App. C. 

Epichlorohydrine Epichlorohydrine is an intermediate chemical with an annual production rate of 1.2 million tons (2007) worldwide and is used mainly for epoxy resins (80%) and elastomers [45], It is produced in a multistep process from propene using chlorine and base, releasing a major amount of chloride waste. An alternative process starting vice versa from glycerol was patented by several producers (Dow Chemical, Solvay, and Spolchemie) [46], Plants with a total capacity of approximately 100,000 tons/year are in operation, while plants with greater capacities ( 250,000 tons/year) are under construction [38], With them, approximately 25% of the worldwide production will produced from glycerol by the end of the decade. 

Epichlorohydrin (ECH) is made from propylene, the majority is via allyl chloride intermediate. Total consumption in 1999 was about 600 million lb. Uses for ECH include epoxy resins (65%), synthetic glycerin (22%), and others (paper treatment, specialty ionic exchange resin, glycerol, and glycidol derivatives). 

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