Meta-cresol

Musk ambrette, which is usually regarded as the finest of all the artificial musks, is a nitro-compound of the methyl ether of butyl-meta-cresol, usually described as dinitro-butyl- ieia-cresol methyl ether. It should melt at 85°. 

Into an iron or copper reaction vessel having an efficient stirring device and furnished with a refluxing column and condenser, were charged 330 lb of high quality meta-cresol and 150 lb of glycerol, together with 25 lb of sodium acetate to serve as the catalyst in the reaction. 

Alkyl-substituted phenols have different reactivities than phenol toward reaction with formaldehyde. Relative reactivities determined by monitoring the disappearance of formaldehyde in phenol-paraformaldehyde reactions (Table 7.3) show that, under basic conditions, meta-cresol reacts with formaldehyde approximately three times faster titan phenol while ortho- and para-cresols react at approximately one-third the rate of phenol.18 Similar trends were observed for the reactivities of acid-catalyzed phenolic monomers with formaldehyde. 

The oxidation of phenol, ortho/meta cresols and tyrosine with Oj over copper acetate-based catalysts at 298 K is shown in Table 3 [7]. In all the cases, the main product was the ortho hydroxylated diphenol product (and the corresponding orthoquinones). Again, the catalytic efficiency (turnover numbers) of the copper atoms are higher in the encapsulated state compared to that in the "neat" copper acetate. From a linear correlation observed [7] between the concentration of the copper acetate dimers in the molecular sieves (from ESR spectroscopic data) and the conversion of various phenols (Fig. 5), we had postulated [8] that dimeric copper atoms are the active sites in the activation of dioxygen in zeolite catalysts containing encapsulated copper acetate complexes. The high substratespecificity (for mono-... 

With an effective strategy for construction of the diazofluorene established, we set out to prepare the coupling partners required for synthesis of (—)-kinamycin F (6). The synthesis of the enone 117 began with meta-cresol (128, Scheme 3.23). Silylation formed the silyl ether 119 in nearly quantitative yield. Birch reduction of the silyl ether 119 formed the cyclohexadiene derivative 129 in excellent yield. Asymmetric dihydroxylation [52] of 129 occurred regioselectively to afford the... 

The novolac sample, which was provided by Kodak, was synthesized from pure meta-cresol and formaldehyde. It has a weight average molecular weight of 13,000 and a very broad polydispersity of 8.5. The polymer was purified by two precipitations from tetrahydrofuran into hexane. The PAC was a naphthoquinone-1,2-(diazide-2-)-5-sulfonyl ester provided by Fairmount Chemical (Positive Sensitizer 1010). A hydroxyl substituted benzophenone is attached to the sulfonyl ester. The spreading solvent was isopropyl acetate, which was obtained from Aldrich Chemicals and used as received. 

Determining the equilibrium relationships for a multicomponent mixture experimentally requires a considerable quantity of data, and one of two methods of simplification is usually adopted. For many systems, particularly those consisting of chemically similar substances, the relative volatilities of the components remain constant over a wide range of temperature and composition. This is illustrated in Table 11.2 for mixtures of phenol, ortho and meta-cresols, and xylenols, where the volatilities are shown relative to ortho-cresol. 

FIGURE 8 Analysis of the test mixture with (A) the SDS MEKC system containing 10 mM phosphate buffer (pH 7.5), 60 mM SDS, and 10% acetonitrile and (B) the CTAB MEKC system containing 25 mM phosphate buffer (pH 7.5), 10 mM CTAB, and 10% acetonitrile. Peaks I formamide 2 pyridine 3 aniline 4 meta-cresol 5 phenyl acetate 6 nitrobenzene 7 benzoic acid 8 thiamine 9 ethyl benzoate. (Reprinted from reference 270, with permission.)... 

Three types of closely related cresols exist ortho-cresol (o-cresol), meta- cresol (m-cresol), and para-cresol (p-cresol). Pure cresols are colorless chemicals, but they may be found in brown mixtures such as creosote and cresylic acids (e.g., wood preservatives). Because these three types of cresols are manufactured separately and as mixtures, they can be found both separately and together. Cresols can be either solid or liquid, depending on how pure they are pure cresols are solid, while mixtures tend to be liquid. Cresols have a medicinal smell (odor) and when dissolved in water, they give it a medicinal smell and taste. Cresols do not evaporate quickly from water, but in rivers and lakes, they can be removed quickly by bacteria. Dissolved cresols can pass through soil into underground water sources. This may be a problem at hazardous waste sites where cresols are buried. Once cresols are in the water table, they may stay there for months without changing. Cresols in air quickly change and break down into smaller chemicals, some of which irritate the eyes. Cresols can also irritate the eyes. 

Hazleton Labs. 1988d. Mutagenicity tests on meta-cresol and para-cresol inthe in vitro transformation of BALB/C-3T3 cells assay. Unpublished datasubmitted to EPA/OTS. Fiche no. OTS0517694. 

Hazleton Labs. 1989c. Mutagenicity test on cresol program panel sample 2 meta-cresol in the mouse bone marrow cytogenetic assay. HLA study no. 10002-0- 451. Unpublished data submitted to Chemical Manufacturers Association,Washington, DC. 

MBA. 1988c. Subchronic toxicity of meta-cresol in Sprague Dawley rats. Unpublished data submitted by Microbiological Associates to EPA. 

Numerous studies have probed how novolac microstructure influences resist lithographic properties. In one example, a series of resists were formulated from novolacs prepared with varying feed ratios ofpara-l/neta-ctesol. These researchers found that the dissolution rate decreased, and the resist contrast increased, as the para-/tneta-cresol feed ratio increased (33). Condensation can only occur at the ortho position ofpara-o.resol, but can occur at both the ortho- and ra-positions of meta-cresol. It is believed that increased steric factors and chain rigidity that accompany increasedpara-ctescA content modify the polymer solubility. 

Isophane insulin is a white suspension of rod-shaped crystals approximately 30- Jm long, and free from large aggregates of crystals after being subjected to moderate agitation. It contains either 1.4-1.8% glycerol, 0.15-0.17% meta-cresol, and 0.06-0.07% phenol on a wt/vol basis, or 1.4—1.8% glycerol and 0.20-0.25% phenol (wt/vol), at a pH of 7.1-7.4. It also contains 0.15-0.25% (wt/vol) of sodium phosphate, 0.01-0.04 mg of zinc, and 0.3—0.6 mg of protamine for each USP insulin unit. The insoluble matter in the suspension is crystalline and contains not more than traces of amorphous material. 

The reaction with thiols takes place in meta-cresol or in acetic acid containing DMF. The slightly acidic medium is needed to favor the protonation of the intermediate species (pathway a) and minimize the reaction with other maleimide units (pathway b) giving crosslinked polymers (Fig. 10). 

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. 

From 100 parts of commercial meta-cresol containing only 60% of the m- isomer (the rest being p- cresol) not more than 100 parts of trinitro-m-cresol can be obtained, p- Cresol is fully oxidized to oxalic acid, which then crystallizes from the spent acid. 

In the absence of any other criteria, a sample of each meta-cresol batch to be nitrated should be subjected to a laboratory nitration test. 

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