Phenolics Phenols

Phenol-, phenol, phenol-, phenolic (in com-bination with the name of a metal) phenoxide (or phenolate) of, as Phenolaluminium, aluminum phenoxide, aluminum phenolate, phenolartig, a. of the nature of or like a phenol, phenoloid. 

In the past, different authors had different views on the classification of alcohols in tobacco and tobacco smoke. In onr catalog, we employ a system different from those used by our forerunners. In 1954, Kosak (2170), in his smoke component compilation, listed seven alcohols four alcohols (methanol, glycerol, diethylene glycol, and ethylene glycol) and three phenols (phenol, phenols, and catechol). He did not list either levoglucosan or a phytosterol as an alcohol but listed both as miscellaneous smoke components. In 1959, Johnstone and Plimmer (1971) listed thirteen alcohols plus five phytosterols identified in tobacco and/or smoke. 

Epoxy phenolic phenolic phenolic formaldehyde formaldehyde formaldehyde formaldehyde Polyaromatic Polyester Polyurethane Anaerobic Cyanoacrylate acrylic... 

Phenolic compounds are commonplace natural products Figure 24 2 presents a sampling of some naturally occurring phenols Phenolic natural products can arise by a number of different biosynthetic pathways In animals aromatic rings are hydroxylated by way of arene oxide intermediates formed by the enzyme catalyzed reaction between an aromatic ring and molecular oxygen... 

Sta.rting from Phenol. Phenol can be selectively oxidized into -benzoquinone with oxygen. The reaction is catalyzed by cuprous chloride. At low catalyst concentration, the principal drawback of this method is the high pressure of oxygen that is required, leading to difficult safety procedures. It appears that a high concentration of the catalyst (50% of Cu(I)—phenol) allows the reaction to proceed at atmospheric pressure (58). 

Phenolics. Phenol (qv) and the chlotinated phenoHcs formerly comprised the largest class of iadustrial antimicrobials (see Chlorophenols). Table 5 shows the remaining phenoHcs of importance. Use of pentachlorophenol has been severely restricted only one manufacturer suppHes product for the wood preservation market. 

Substituted Phenols. Phenol itself is used in the largest volume, but substituted phenols are used for specialty resins (Table 2). Substituted phenols are typically alkylated phenols made from phenol and a corresponding a-olefin with acid catalysts (13). Acidic catalysis is frequendy in the form of an ion-exchange resin (lER) and the reaction proceeds preferentially in the para position. For example, in the production of /-butylphenol using isobutylene, the product is >95% para-substituted. The incorporation of alkyl phenols into the resin reduces reactivity, hardness, cross-link density, and color formation, but increases solubiHty in nonpolar solvents, dexibiHty, and compatibiHty with natural oils. 

Phenol. Phenol monomer is highly toxic and absorption by the skin can cause severe blistering. Large quantities can cause paralysis of the central nervous system and death. Ingestion of minor amounts may damage kidneys, Hver, and pancreas. Inhalation can cause headaches, dizziness, vomiting, and heart failure. The threshold limit value (TLV) for phenol is 5 ppm. The health and environmental risks of phenol and alkylated phenols, such as cresols and butylphenols, have been reviewed (66). 

Phenols. Phenols are unreactive toward chloroformates at room temperature and at elevated temperatures the yields of carbonates are relatively poor (< 10%) in the absence of catalysis. Many catalysts have been claimed in the patent Hterature that lead to high yields of carbonates from phenol and chloroformates. The use of catalyst is even more essential in the reaction of phenols and aryl chloroformates. Among the catalysts claimed are amphoteric metals or thek haUdes (16), magnesium haUdes (17), magnesium or manganese (18), secondary or tertiary amines such as imidazole (19), pyridine, quinoline, picoline (20—22), heterocycHc basic compounds (23) and carbonamides, thiocarbonamides, phosphoroamides, and sulfonamides (24). 

Reaction with Phenols. Phenols react with diphenyl carbonate in the presence of bases or organometaHic catalysts to produce diaryl carbonates. A specific example is the reaction of diphenyl carbonate with bisphenol A [80-05-7] to produce polycarbonate. 

The procedure of simultaneous extracting-spectrophotometric determination of nitrophenols in wastewater is proposed on the example of the analysis of mixtures of mono-, di-, and trinitrophenols. The procedure consists of extraction concentrating in an acid medium, and sequential back-extractions under various pH. Such procedures give possibility for isolation o-, m-, p-nitrophenols, a-, P-, y-dinitrophenols and trinitrophenol in separate groups. Simultaneous determination is carried out by summary light-absorption of nitrophenol-ions. The error of determination concentrations on maximum contaminant level in natural waters doesn t exceed 10%. The peculiarities of application of the sequential extractions under fixed pH were studied on the example of mixture of simplest phenols (phenol, o-, m-, />-cresols). The procedure of their determination is based on the extraction to carbon tetrachloride, subsequent back-extraction and spectrophotometric measurement of interaction products with diazo-p-nitroaniline. 

Phenolics. Phenol-formaldehyde (Bakelite) is one of the oldest synthetic materials available. It is a strong, hard, brittle material with good creep resistance and excellent electrical properties. Unfortunately the material is only available in dark colours and it is susceptible to attack by alkalis and oxidising agents. Typical applications are domestic electrical fittings, saucepan handles, fan blades, smoothing iron handles and pump parts. 

The process has two main sources of waste water. These are the condensate streams from the steam strippers. The principal pollutant in both wastewater streams is phenol. Phenol is of concern primarily because of its toxicity, oxygen depletion, and turbidity. In addition, phenol can cause objectionable taste and odor in fish flesh and potable water. 

Triazine 4-oxides 55 react with phenols (phenol, 2,6-dimethylphenol, resorcinol, 4-hexyh esorcinol) in trifluoroacetic acid in a similar way, yielding intermediate (T -adducts 5-hydroxyphenyl-4-hydroxy-4,5-dihydro-l,2,4-triazines 61. Subsequent oxidation leads to the corresponding 5-hydroxyphenyl-l,2,4-triazine 4-oxides 62 (97MC116). 

Phenolat, n. phenoxide, phenolate. Phenol-ather, m. phenol ether, -carbonsaure, /. phenolcarboxylic acid, -gruppe, /, phenol group,... 

Phenolic phenol formaldehydes (PFs) are the low-cost workhorse of the electrical industry (particularly in the past) low creep, excellent dimensional stability, good chemical resistance, good weatherability. Molded black or brown opaque handles for cookware are familiar applications. Also used as a caramel colored impregnating plastics for wood or cloth laminates, and (with reinforcement) for brake linings and many under-the-hood automotive electricals. There are different grades of phenolics that range from very low cost (with low performances) to high cost (with superior performances). The first of the thermosets to be injection-molded (1909). 

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