摘要:
The aromatic hydroxyl groups of aromatic hydroxyl-containing compounds can be allylated to greater than 95% conversion by reacting the alkali metal salt of said aromatic hydroxyl-containing compounds with an allyl halide such as allyl chloride in the presence of a polar aprotic solvent such as dimethylformamide. These compounds are useful in preparing epoxy resins containing a low halogen content.
摘要:
Halogenated aromatic epoxy resins are disclosed wherein the halogen atoms are in the meta position with respect to a glycidyl ether group attached to an aromatic ring.Advanced epoxy resins are disclosed which result from the reaction of a relatively low molecular weight epoxy resin and a polyhydric phenol wherein at least one of the reactants contains at least one halogen atom which is meta with respect to a glycidyl ether group or a hydroxyl group attached to an aromatic ring. These advanced epoxy resins, when cured with a suitable curing agent, possess an improvement as compared to an advanced epoxy resin containing halogen atoms which are ortho with respect to a glycidyl ether group in at least one of thermal stability, glass transition temperature, relationship of viscosity to molecular weight and resistance to forming hydrolyzed halides in the presence of a refluxing solution of an alkali metal hydroxide.
摘要:
Unwanted halogen values are removed from liquid resin, organic or hydrocarbon material by adding particulate crystalline lithium aluminate compounds to the liquid material to act as a halogen scavenger, then separating the crystalline aluminate compound from the liquid material.
摘要:
A process for the dehydrohalogenation of a (polyhaloalkyl)benzene containing a benzylic halogen such as 1,3-dichloro-5-(2,4,4,4-tetrachlorobutyl)-benzene by contacting the (polyhaloalkyl)benzene with a Lewis acid such as AlCl.sub.3 deposited on an inert support such as silica gel or alumina under conditions sufficient to catalyze said dehydrohalogenation to form a (polyhaloalkenyl)benzene such as 3,5-dichloro-.alpha.-(2,2,2-trichloroethyl)styrene.
摘要:
2,6-dibromo-3,5-dialkyl-4-hydroxybenzyl ethers, glycidyl ethers thereof and reaction products with phenolic hydroxyl-containing compounds, and glycidyl ethers of the resulting new phenolic hydroxyl-containing compounds.
摘要:
Titled materials and their preparation. The materials contain a moiety such as, for example, 4-oxy-3,5-dimethyl-2,6-dibromobenzyl which can impart a high degree of thermal and hydrolytic stability to the materials, for example, epoxy thermosets such as in electronic encapsulations. For example, when used in electronic encapsulation formulations, these materials can provide a substantial increase in electronic device reliability. Their preparation involves an alkylation of an aromatic ring, for example, such as a Friedel-Crafts alkylation with 4-bromomethyl-3,5-dibromo-2,6-dimethylphenol or with 4-hydroxymethyl-3,5-dibromo-2,6-dimethylphenol.
摘要:
Epoxy resins are prepared by reacting an excess of an epihalohydrin with a phenolic hydroxyl-containing compound in the presence of the incremental addition of a basic catalyst while removing water by codistilling with a solvent and epihalohydrin.
摘要:
Advanced epoxy resins are disclosed which result from the reaction of a relatively low molecular weight epoxy resin and a polyhydric phenol wherein at least one of the reactants contains at least one halogen atom which is meta with respect to a glycidyl ether group or a hydroxyl group attached to an aromatic ring. These advanced epoxy resins, when cured with a suitable curing agent, possess an improvement as compared to an advanced epoxy resin containing halogen atoms which are ortho with respect to a glycidyl ether group in at least one of thermal stability, glass transition temperature, relationship of viscosity to molecular weight and resistance to forming hydrolyzed halides in the presence of a refluxing solution of an alkali metal hydroxide.
摘要:
Advanced epoxy resin products are prepared by reacting a triglycidyl ether of a trihydric phenol such as the triglycidyl ether of 1,1,1-tri(hydroxyphenyl)methane with a dihydric phenol such as bisphenol A. These advanced epoxy resins are non-sintering solid resins useful in the preparation of electrical potting or molding compositions.