Mass phenol hydrogenation

In a 500 ml. conical flask place 50 ml. of glachtl acetic acid, 25 ml. of 40 per cent, formaldehyde solution (formalin) and 20 g. of phenol. Wrap a cloth or towel loosely around the neck and opening of the flask. Pass dry hydrogen chloride gas (Section 11,48,1) into the mixture. Within 5 minutes, a large mass of pink plastic is formed the reaction is sometimes very vigorous. The yield is 36 g. It is frequently necessary to break the flask in order to remove the product completely for this reason a beaker, or metal flask or beaker, is preferable. 

The reaction products from 2,4-dichlorophenol were tetrachloro-phenoxyphenols and tetrachlorodihydroxybiphenyls (Figure 5), as determined from their mass spectra and those of their methyl ethers. 4,6-Dichloro-2-(2, 4 -dichlorophenoxy)phenol (V) was the major phenoxy-phenol the mass spectral fragmentation pattern of o-hydroxyphenol ethers is quite characteristic since a hydrogen transfer occurs during the fragmentation (Figure 6). A trace of a trichlorophenoxyphenol also was detected and was formed presumably by the unsensitized reductive loss of chlorine, discussed previously. 

The mass spectrum of aniline has been known since the early days of mass spectrometry. [122] Initially, the observed [M-27] ion has been interpreted in terms of HCN loss (Fig. 6.56a). The mechanism for loss of the elements of [H, N, C] from aminoarenes is perfectly analogous to CO loss from phenols (Chap. 6.9.1). [231] More recently, it could be demonstrated that loss of hydrogen isocyanide, HNC, occurs rather than losing the more stable neutral species HCN, a behavior typical of ionized pyridine. [222]... 

Solubility of alcohols and phenols in water is due to their ability to form hydrogen bonds with water molecules as shown. The solubility decreases with increase in size of alkyl/aryl (hydro-phobic) groups. Several of the lower molecular mass alcohols are miscible with water in all proportions. 

Alcohols are higher boiling than other classes of compounds, namely hydrocarbons, ethers and haloalkanes of comparable molecular masses. The ability of alcohols, phenols and ethers to form intermolecular hydrogen bonding with water makes them soluble In it. 

The mass spectrum of a typical phenol is shown in Figure 2.10. This spectrum shows that a methyl group is lost much more readily than an a hydrogen. 

Lasiodine-A (59) (33), though not a cyclic peptide, exhibits many of the structural features common to that class and could conceivably result from subsequent scission of a cyclic precursor (4). Spectral study identified an isopropylidene, a secondary hydroxyl, a phenolic hydroxyl, and an ester function. Mass spectra fail to reveal the molecular ion but a fragment of mass M-I06 as known from some other peptide alkaloids containing phenylserine as ring bond amino acid (30,31,62). Catalytic hydrogenation generates N-methylvaline and a moiety (83) whose structure was deduced from spectral studies and from hydrolytic degradations. Reduction of the alkaloid with lithiumaluminiumhydride... 

Demethoxyabresoline (67) was obtained as a noncrystalline solid. Spectroscopic investigation revealed the presence of a phenolic OH, a 1-phenyl-quinolizidine system, and a trans-cinnamyl group. The stereochemistry at C-l, C-3, and C-5 was the same as in abresoline. The molecular formula C25H29N05 was established by mass spectrometry. The presence of fragment ions at m/e 259 (M —164) and 258 was characteristic of p-hydroxy-cinnamyl esters of the phenylquinolizidol (63a). The assigned structure 68 was confirmed by basic hydrolysis to 63a and p-hydroxycinnamic acid as well as by catalytic hydrogenation to a known dihydro derivative (52). 

Chromic acid test. This test is able to distinguish primary and secondary alcohols from tertiary alcohols. Using acidified dichromate solution, primary alcohols are oxidized to carboxylic acids secondary alcohols are oxidized to ketones tertiary alcohols are not oxidized. (Note that in those alcohols which are oxidized, the carbon that has the hydroxyl group loses a hydrogen.) In the oxidation, the brown-red color of the chromic acid changes to a blue-green solution. Phenols are oxidized to nondescript brown tarry masses. (Aldehydes are also oxidized under these conditions to carboxylic acids, but ketones remain intact see Experiment 31 for further discussion.)... 

In order to get a qualitative idea, Table 5.6 presents kinetic constants for the consecutive/parallel reaction scheme given in Figure 5.1 obtained with a Pd-type catalyst (Park et al. [15]). Hydrogen was in large excess so that first-order kinetics may be assumed. Note that kinetic constants are reported as the mass load W/Fphenoi. the phenol being produced by the evaporation of aqueous solutions. The nature of the support is the determinant for selectivity, but the activity is also affected. The most selective catalyst is Pd deposited on activated carbon (AC), but... 

Pignatello, J.J. (1992) Dark and photoassisted iron (3+)-catalyzed degradation of chlorophenoxy herbicides by hydrogen peroxide. Environ. Sci. Technol. 26, 944-951 Polcaro, A.M., Mascia, M, Palmas, S. and Vacca, A. (2002) Electrochemical oxidation of phenolic and other organic compounds at boron doped diamond electrodes for wastewater treatment Effect of mass transfer. Ann. Chim. 93, 967-976... 

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