Cresol content

To reduce cresol content in discharged wastewater sOeams, four MSAs are avaiiaUe two MS As to remove cresol from gaseous stress and two MSAs to remove cresol from liquid streams. Tables 7.4. and 7.5. provide data for the candidate MSAs. 

Table VI compares results from air, dust and slurry investigations on VFA and phenolic/indolic compounds in piggeries. Relative values are used. When comparing the results derived from investigations on dust, air or slurry it is necessary to use relative values because of the different dimensions, for experience shows that in spite of large quantitative differences between two samples within the group of carboxylic acids and within the group of phenolic/indolic compounds the proportions of the components remain rather stable (36). In the group of VFA acetic acid is the main component in air, dust, and slurry followed by propionic and butyric acid. The other three acids amount to less than 25%. In the group of phenols/ indoles p-cresol is the main component in the four cited investigations. However, it seems that straw bedding can reduce the p-cresol content in this case phenol is the main component, instead (37).

This method is capable of producing p- or m-cresol from the corresponding cymene (isopropyltoluene). Alkaline chlorotoluene hydrolysis is used to formulate a cresol mixture with a high m-cresol content. However, information pertaining to domestic use of this process was unavailable (Fiege and Bayer 1987). 

Tricresylphosphate from receptacle 9 enters flusher 11, which is a cylindrical apparatus with an agitator. First of all, tricresylphosphate is washed with 3% sodium hydroxide to neutralise residual hydrochloric acid and separate cresol (the allowable cresol content in tricresylphosphate is 0.6 g/1). It is also recommended to treat the product with diluted solution of potassium permanganate to improve the colour and oxidation stability of tricresylphosphate. 

Cresol for nitration should contain a high proportion of the m- isomer. Commercial meta-cresol usually contains about 60% of the m- isomer and 40% of p- cresol. The preparation of a much more costly raw material, containing 90% of m- cresol is also possible. It is clear that the yield of trinitro-m-cresol will correspond to the m- cresol content in the starting product. 

Under controlled (mild) sulfonation conditions and relatively mild caustic fusion, it is possible to produce cresols mixture with very small (less than 1%) meta-cresol content. 

Caustic soda is commonly used as the catalyst for the manufacture of resols for mechanical and decorative laminates. However, it is not used in electrical laminates because it adversely affects the electrical insulation properties. For electrical-grade resols ammonia is the usual catalyst, and the resins are usually dissolved in industrial methylated spirits. The use of cresylic acid (m-cresol content 50-55%) in place of phenol yields laminating resins of better electrical properties. 

Figure 2. Inter-relationships between viscosity of polyaniline doped with d,l camphor sulfonic acid in solutions of cholorform and m-cresol of increasing m-cresol content and electronic spectra, conductivity, dielectric constant and x-ray diffraction spectra of free-standing films (cast from the 3.0 wt.% solutions of the composition indicated). Viscosity studies and spun films for Vis/UV studies employed 0.33 wt.% solutlons,24 25.

It is observed that the molecular weight of copolymers increase with increase in p-cresol content. This observation is in agreement with the trend observed by earUer workers (Michel et al., 2007 Shah et al., 2006). 

A particular mode of neurotoxicity was discovered for tricresyl phosphate that correlated with the presence of the o-cresyl isomer (or certain other specific aLkylphenyl isomers) in the triaryl phosphates. Many details of the chemistry and biochemistry of the toxic process have been elucidated (139,140,143—146). The use of low ortho-content cresols has become the accepted practice in industrial production of tricresyl phosphate. Standard in vivo tests, usually conducted with chickens sensitive to this mode of toxicity, have been developed for premarket testing of new or modified triaryl phosphates. As of 1992, the EPA called for extensive new toxicity and environmental data on this group of products (147). The Vederal e ster AoQ xm. ci. calling for this... 

Laminates. Laminate manufacture involves the impregnation of a web with a Hquid phenoHc resin in a dip-coating operation. Solvent type, resin concentration, and viscosity determine the degree of fiber penetration. The treated web is dried in an oven and the resin cures, sometimes to the B-stage (semicured). Final resin content is between 30 and 70%. The dry sheet is cut and stacked, ready for lamination. In the curing step, multilayers of laminate are stacked or laid up in a press and cured at 150—175°C for several hours. The resins are generally low molecular weight resoles, which have been neutralized with the salt removed. Common carrier solvents for the varnish include acetone, alcohol, and toluene. Alkylated phenols such as cresols improve flexibiUty and moisture resistance in the fused products. 

In the case of low temperature tar, the aqueous Hquor that accompanies the cmde tar contains between 1 and 1.5% by weight of soluble tar acids, eg, phenol, cresols, and dihydroxybenzenes. Both for the sake of economics and effluent purification, it is necessary to recover these, usually by the Lurgi Phenosolvan process based on the selective extraction of the tar acids with butyl or isobutyl acetate. The recovered phenols are separated by fractional distillation into monohydroxybenzenes, mainly phenol and cresols, and dihydroxybenzenes, mainly (9-dihydroxybenzene (catechol), methyl (9-dihydtoxybenzene, (methyl catechol), and y -dihydroxybenzene (resorcinol). The monohydric phenol fraction is added to the cmde tar acids extracted from the tar for further refining, whereas the dihydric phenol fraction is incorporated in wood-preservation creosote or sold to adhesive manufacturers. Naphthalene Oils. Naphthalene is the principal component of coke-oven tats and the only component that can be concentrated to a reasonably high content on primary distillation. Naphthalene oils from coke-oven tars distilled in a modem pipe stiU generally contain 60—65% of naphthalene. They are further upgraded by a number of methods. 

Methylene chloride is one of the more stable of the chlorinated hydrocarbon solvents. Its initial thermal degradation temperature is 120°C in dry air (1). This temperature decreases as the moisture content increases. The reaction produces mainly HCl with trace amounts of phosgene. Decomposition under these conditions can be inhibited by the addition of small quantities (0.0001—1.0%) of phenoHc compounds, eg, phenol, hydroquinone, -cresol, resorcinol, thymol, and 1-naphthol (2). Stabilization may also be effected by the addition of small amounts of amines (3) or a mixture of nitromethane and 1,4-dioxane. The latter diminishes attack on aluminum and inhibits kon-catalyzed reactions of methylene chloride (4). The addition of small amounts of epoxides can also inhibit aluminum reactions catalyzed by iron (5). On prolonged contact with water, methylene chloride hydrolyzes very slowly, forming HCl as the primary product. On prolonged heating with water in a sealed vessel at 140—170°C, methylene chloride yields formaldehyde and hydrochloric acid as shown by the following equation (6). 

The (9-cresol novolaks of commercial significance possess degrees of polymerization, n, of 1.7—4.4 and the epoxide functionaUty of the resultant glycidylated resins varies from 2.7 to 5.4. Softening points (Durran s) of the products are 35—99°C. The glycidylated phenol and o-cresol—novolak resins are soluble in ketones, 2-ethoxyethyl acetate, and toluene solvents. The commercial epoxy novolak products possess a residual hydrolyzable chlorine content of <0.15 wt% and a total chlorine content of ca 0.6 wt % (Table 2). 

Pure ortho-cresol melting at 30° should be employed, and the results obtained with mixtures of known cineol content were as follows —... 

A sample of polyester (ca. 1 g, exactly weighed) is dissolved in 20 mL toluene-ethanol mixture (1/1 vol.) and titrated by a solution of KOH in ethanol (0.05 mol/L) using a potentiometric titrator. A blank titration must be performed under the same conditions. Hardly soluble polyesters (e.g., PET) must be dissolved in an o-cresol-chloroform mixture or in hot benzyl alcohol.417 The result (acid content) is normally expressed in mmol COOH/g polyester but may also be given as the acid number, defined as the number of milligrams of KOH required to neutralize 1 g of polyester. [Acid number = (number of mmol COOH/g polyester) x 56.106.]... 

This interpretation is further confirmed by the results obtained in the liquid-phase methylation of m-cresol with Mg/Fe mixed oxides having different Fe contents Mgi.xFexOi+i/2x. In these catalysts the number of Lewis acid sites was proportional to the Fe content [4], Figure 4 plots the selectivity parameters and the number of Lewis acid sites as a function of the Mg/Fe ratio in catalysts (selectivity was calculated at very low m-cresol conversion, thus in the absence of any consecutive reaction). 

The classic work of Storch and co-workers showed that essentially all coals below 89% C f can be converted in high yields to acetone soluble materials on extended reaction (12). We have investigated the behavior of coals of varying rank toward short contact time liquefaction. In one series of experiments, coals were admixed with about 5 volumes of a solvent of limited H-donor content (8.5% Tetralin) and heated to 425°C for either 3 or 90 minutes. The solvent also contained 18% p-cresol, 2% y-picolene, and 71.5% 2-methylnaphthalene and represented a synthetic SRC recycle solvent. The conversions of a variety of coals with this... 

See also Epoxy coatings Epoxy chalcone, 10 450 12,13-Epoxy-cis-9-octadecenoic (vernolic) acid, physical properties, 5 35t Epoxy coatings, 10 436 450 17 845. See also Epoxy can coatings for corrosion protection, 7 199 markets for, 10 442-449 performance of, 10 423 waterborne, 10 439 Epoxy composites, 10 450, 451 Epoxy compounds, photoinitiated polymerization of, 23 716 Epoxy content analysis, 10 385 Epoxy cresol novolac (ECN) resins, 10 367, 369... 

A series of o-cresol novolac-PDMSX materials with a range of silicon contents (3.2-16.1 wt %) were prepared to examine the O2 REE response and to determine whether a solubility limit existed as a function of wt % silicon. All copolymer preparations exhibited good solubility in dilute TMAH and an asymptotic relationship (12) between wt % silicon and film thickness loss (3,12) during an 02 plasma RIE process was found. 

The incorporation of PDMSX into conventional novolac resins has produced potential bilevel resist materials. Adequate silicon contents necessary for O2 RIE resistance can be achieved without sacrificing aqueous TMAH solubility. Positive resist formulations using an o-cresol novolac-PDMSX (510 g/mole) copolymer with a diazonaphthoquinone dissolution inhibitor have demonstrated a resolution of coded 0.5 pm L/S patterns at a dose of 156 mJ/cm2 upon deep-UV irradiation. A 1 18 O2 etching selectivity versus hard-baked photoresist allows dry pattern transfer into the bilevel structure. 

Acetylated m-cresol novolac copolymers were prepared by acetylation of m-cresol novolac with acetic anhydride in the presence of sodium hydroxide. The following acetylation procedure is typical. 3.2g of sodium hydroxide (50 mmol) was added to 4.8g of cresol novolac (40mmol) in 10 ml. of water. The reaction mixture was stirred for 10 mins, until all polymer went into solution. The required amount of acetic anhydride was then added, the reaction mixture was stirred for 10 more mins, and poured in 150 ml. of iced water. The polymer was filtered and purified by reprecipitation from a chloroform/benzene (5 2 v/v) solution by the addition of hexane. The acetylation content was determined by H and 13C NMR. 

Table V gives quantitative values of volatile fatty acids and phenolic/indolic compounds found in the aerosol phase and in settled dust of piggeries, respectively. The results from the aerosol phase coincide, particularly as far as acetic acid is concerned. For the investigations of the settled dust the coefficients of variation (CV) and the relative values (%) characterizing the percentage of the single compounds as part of the total amount are quoted. The values are corrected with the dry matter content of the dust. Main components are acetic acid andp-cresol, respectively.

Overall, dissolution in the electrolyte solutions of all studied compounds led to substantial decreases in their concentrations in the original crude oil. However, the rate of decrease was different for each compound, in accordance with the molecular properties. Bennett and Larter (1997) note that, in comparison with the original crude oil, the concentration of phenol decreased relative to cresol. The change in phenol content relative to cresol is highlighted by measuring the ratio (phenol/o- -i-m- + p- cresol), which shows that the reduction of more hydrophilic phenol relative to cresol is in accord with their relative dissolution in water. 

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