Phenol specifications

The US. Pharmacopeia (USP) specification for phenol includes (/) purity is to be no less than 98 wt %, (2) clear solubiUty of 1 part of phenol in 15 parts of water, (2) a congealing temperature to be not lower than 39°C, and (4) a content of nonvolatiles of no more than 0.05 wt %. Commercially, phenol specifications far exceed the USP requirement. Typical commercial phenol specifications are Hsted in Table 5. Higher purity material is required for some apphcations. 

Cells of Desulfomonile tiedjei induced by growth with 3-chlorobenzoate were able to partially dechlorinate polychlorinated phenols, specifically at the 3-position, whereas the monochlorophenols were apparently resistant to dechlorination (Mohn and Kennedy 1992). Details of the reductase have already been described in Part 1 of this chapter. 

Phenol-specific immunoassay has also been used as a detection system in liquid chromatographic separation system [111]. The connection between HPLC and immunoassay detection was regarded by the authors to be more labor demanding than conventional HPLC-UV, but the payoff in selectivity and sensitivity is claimed to be immense. 

Catechol is produced by coproduction with hydroquinone starting from phenol. Other techniques such as coal extraction remain marginal. The installed capacities (- 25,000 t/yr) are now sufficient to cover the demand. Catechol is mainly used for synthesis in food, pharmaceutical, or agrochemical ingredients. A specific appHcation of / fZ-butylcatechol is as a polymerisation inhibitor. 

Phosphonothioate Esters of Phenols. Phosphonates with a single P—C bond are highly toxic and persistent iasecticides but have not been used extensively because some compounds produce delayed neuropathy leading to irreversible paralysis ia higher animals, including humans. Such compounds specifically inhibit an enzyme, neurotoxic esterase, that is responsible for the growth and maintenance of long nerve axons (31,32). 

Epoxidized phenol novolak and cresol novolak are the most common curing agents. The composition of the resin and hardener system is optimized for each specific appHcation eg, incorporating phenol novolaks in the matrix resin can iacrease cure speed. 

Oxygen levels in the VGO parallel the nitrogen content. Thus, the most identified oxygen compounds are phenols and carboxyUc acids, frequendy called naphthenic acids. These may account for from ppm to neady 3% of a VGO. The presence of numerous complex naphthenic and naphtheno aromatic acid stmctures in cmde oils, especially immature forms, has been shown (34). Among the different stmctures a number of specific steroid carboxyUc acids have been identified. 

Resoles. Like the novolak processes, a typical resole process consists of reaction, dehydration, and finishing. Phenol and formaldehyde solution are added all at once to the reactor at a molar ratio of formaldehyde to phenol of 1.2—3.0 1. Catalyst is added and the pH is checked and adjusted if necessary. The catalyst concentration can range from 1—5% for NaOH, 3—6% for Ba(OH)2, and 6—12% for hexa. A reaction temperature of 80—95°C is used with vacuum-reflux control. The high concentration of water and lower enthalpy compared to novolaks allows better exotherm control. In the reaction phase, the temperature is held at 80—90°C and vacuum-refluxing lasts from 1—3 h as determined in the development phase. SoHd resins and certain hquid resins are dehydrated as quickly as possible to prevent overreacting or gelation. The end point is found by manual determination of a specific hot-plate gel time, which decreases as the polymerization advances. Automation includes on-line viscosity measurement, gc, and gpc. 

Alkylphenols can be synthesized by several approaches, including alkylation of a phenol, hydroxylation of an alkylbenzene, dehydrogenation of an alkylcyclohexanol, or ring closure of an appropriately substituted acycHc compound. The choice of approach depends on the target alkylphenol, availabihty of the starting materials, and cost of processing. The procedures discussed herein encompass commercial methods, general methods, and a few specific examples of commercial interest. 

All lation of Phenols. The approach used to synthesize commercially available alkylphenols is Friedel-Crafts alkylation. The specific procedure typically uses an alkene as the alkylating agent and an acid catalyst, generally a sulfonic acid. Alkene and catalyst interact to form a carbocation and counter ion (5) which interacts with phenol to form a 7T complex (6). This complex is held together by the overlap of the filled TT-orbital of the aromatic... 

DOT 17E phenolic-lined steel pails and dmms, respectively. Plain steel is not suitable for isopropyl alcohol containing water because msting can result. Instead, baked phenolic-lined steel tanks are used. Aluminum is also unsuitable. It is attacked by isopropyl alcohol, especially the anhydrous grade, resulting ia the formation of aluminum isopropoxide. Containers must comply with DOT specifications. Tanks, piping, and equipment can be made of similar material. 

These specifications include specific gravity, maximum water content, maximum values for toluene- or ben2ene-insoluble material, and maximum amounts distilling at 230°C, 270°C, 315°C, and 355°C. In the case of the AWPA specifications, there are minimum limits to the specific gravities of each of the distillate fractions in the case of the WEI specifications, limits for the contents of ben2o[a]pyrene and water-soluble phenols (tar acids). 

Phenolics are consumed at roughly half the volume of PVC, and all other plastics are consumed in low volume quantities, mosdy in single apphcation niches, unlike workhorse resins such as PVC, phenoHc, urea—melamine, and polyurethane. More expensive engineering resins have a very limited role in the building materials sector except where specific value-added properties for a premium are justified. Except for the potential role of recycled engineering plastics in certain appHcations, the competitive nature of this market and the emphasis placed on end use economics indicates that commodity plastics will continue to dominate in consumption. The apphcation content of each resin type is noted in Table 2. Comparative prices can be seen in Table 5. The most dynamic growth among important sector resins has been seen with phenoHc, acryUc, polyurethane, LLDPE/LDPE, PVC, and polystyrene. 

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. 

Phenol Coefficient Test. The first important attempt at standardizing testing methods was known as the phenol coefficient test (96). It has been modified several times, and is an official AO AC screening test recognized by EPA and PDA. The phenol coefficient test compares the activity of disinfectants to that of phenol, under specific conditions, to give a number that measures the activity of the chemical tested with respect to that of phenol, ie, the phenol coefficient. The AO AC method employs visual examination of bacterial growth in a nutrient medium. The Kelsey-Sykes test (1969) is a modified method popular in British circles. 

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