Phenolic estimation

ISO 6843 1988, Surface active agents Sulfated ethoxylated alcohols and alkyl-phenols—Estimation of the mean relative molecular mass. 

FIGURE 8. Tentative deactivation scheme of HB and similar compounds S] (phenol) estimated from absorption maximum of HB (solid arrow) AH from MSA ... 

W12. Weame, J. T., Nonspecificity of hypochlorite-phenol estimation of ammonium in biological material. Anal. Chem. 36, 327-328 (1963). 

A last point is the limit of the use of the second derivative for real samples with interferences (suspended solids, other solutes, etc.). The basic assumption is that the derivative value resulting from interferences is close to zero inside the peak or shoulder wavelength range. This is possible when the corresponding spectra part can be considered to be linear (Fig. 4). The only case where the second derivative can be used for phenol estimation is for sample 2, around 290 nm where the initial spectra is linear (and close to zero). Notice that in the 240-nm region, the interferences influence (very strong on initial spectra) leads to the impossibility of considering the second derivative for use other than qualitative information. 

Clove oil, distilled from the unripe blossoms of Eugenia caryo-phyllata, the chief source of which is blast Africa (Zanzibar and Pemba), Specific gravity at 15 C., 1 045-1 061 optical rotation, slightly lavo-rotatory up to 1 30 phenols, estimated by absorp-... 

Pimento oil (allspice), distilled from the fruit of Pimenta officinalis, which is found in the West Indies and Central America. Specific gravity at 15° C., 1 040-1 060 optical rotation, slightly laevo-rotatory up to-4° refractive index at 20° C., 1 529-1 536 phenols, estimated... 

Based on known ocpcrimontal AG values, and Q, were estimated. The system phenol-HMPA in CCI4. was chosen as the reference standard the H-boud free energy factors C, and Q were set at -2.50 (phenol) and 4,00 (HMPA) respectively. 

Estimation of the Number of Hydroxyl Groups in a given Polyhydric Alcohol or Phenol. 

The method is based on the conversion of urea to amnionium carbonate and the estimation of the latter by titration with standard acid. For this purpose, two equal quantities of urea (or urine) are measured out into two flasks A and B. A is treated with 10 ml. of a strong urease preparation and some phenol-phthalein, warm water is added and the mixture is adjusted by the addition of V/io HCl from a burette A until the red colour is just discharged. This brings the mixture to about pH 8 (the optimum for urease) and also prevents loss of ammonia. 

Krypton clathrates have been prepared with hydroquinone and phenol. 85Kr has found recent application in chemical analysis. By imbedding the isotope in various solids, kryptonates are formed. The activity of these kryptonates is sensitive to chemical reactions at the surface. Estimates of the concentration of reactants are therefore made possible. Krypton is used in certain photographic flash lamps for high-speed photography. Uses thus far have been limited because of its high cost. Krypton gas presently costs about 30/1. 

The polymers dissolve in l,l,l,3,3,3-hexafluoro-2-propanol [920-66-1/, hot phenols, and /V, /V- dim ethyl form am i de [68-12-2] near its boiling point. The excellent solvent resistance notwithstanding, solvents suitable for measurement of intrinsic viscosity, useflil for estimation of molecular weight, are known (13,15). 

The cumene oxidation route is the lea ding commercial process of synthetic phenol production, accounting for more than 95% of phenol produced in the world. The remainder of synthetic phenol is produced by the toluene oxidation route via benzoic acid. Other processes including benzene via cyclohexane, benzene sulfonation, benzene chlorination, and benzene oxychl orin ation have also been used in the manufacture of phenol. A Hst of U.S. phenol production plants and their estimated capacities in 1994 are shown in Table 2, and worldwide plants and capacities are shown in Table 3. 

Table 3. Estimated World Synthetic Phenol Capacity/ 1994...

Much work on the hydroperoxidation of triisopropylbenzene to make phloroglucinol, similar to the process of phenol from cumene, has been reported (149—155). The shortest route is based on readily available 4-chlororesorcinol. World production of phloroglucinol is estimated to be in excess of 200 metric tons aimuaHy (156). 

Production of a-methylstyrene (AMS) from cumene by dehydrogenation was practiced commercially by Dow until 1977. It is now produced as a by-product in the production of phenol and acetone from cumene. Cumene is manufactured by alkylation of benzene with propylene. In the phenol—acetone process, cumene is oxidized in the Hquid phase thermally to cumene hydroperoxide. The hydroperoxide is spHt into phenol and acetone by a cleavage reaction catalyzed by sulfur dioxide. Up to 2% of the cumene is converted to a-methylstyrene. Phenol and acetone are large-volume chemicals and the supply of the by-product a-methylstyrene is weU in excess of its demand. Producers are forced to hydrogenate it back to cumene for recycle to the phenol—acetone plant. Estimated plant capacities of the U.S. producers of a-methylstyrene are Hsted in Table 13 (80). 

Cumene production follows the demand for phenol and its derivatives. In 1987, the U.S. cumene demand, estimated at 1.9 million metric tons, was supphed by about 1.8 million metric tons of domestic production imports made up the balance. Based on a trend from 1985 on, the demand is projected to increase at about 3% per year through 1995. 

Example 11 The AGy29s of phenol is estimated using Table 2-388. The molecular groups are... 

For selective estimation of phenols pollution of environment such chromatographic methods as gas chromatography with flame-ionization detector (ISO method 8165) and high performance liquid chromatography with UV-detector (EPA method 625) is recommended. For determination of phenol, cresols, chlorophenols in environmental samples application of HPLC with amperometric detector is perspective. Phenols and chlorophenols can be easy oxidized and determined with high sensitivity on carbon-glass electrode. 

It is found that observed values of Tg for the bis-phenol A polycarbonate are somewhat higher than estimated from data by the general rule-of-thumb relation ... 

Recent estimates suggest that in the early 1990s the percentage breakdown of consumption of phenolic moulding materials in Western Europe was approximately ... 

Example 4.10 A circular plate with a diameter of 0.3 m is to be compression moulded from phenol formaldehyde. If the preform is cylindrical with a diameter of 50 mm and a depth of 36 mm estimate the platen force needed to produce the plate in 10 seconds. The viscosity of the phenol may be taken as 10 Ns/m. ... 

Cost estimation and screening external MSAs To determine which external MSA should be used to remove this load, it is necessary to determine the supply and target compositions as well as unit cost data for each MSA. Towards this end, one ought to consider the various processes undergone by each MSA. For instance, activated carbon, S3, has an equilibrium relation (adsorption isotherm) for adsorbing phenol that is linear up to a lean-phase mass fraction of 0.11, after which activated carbon is quickly saturated and the adsorption isotherm levels off. Hence, JC3 is taken as 0.11. It is also necessary to check the thermodynamic feasibility of this composition. Equation (3.5a) can be used to calculate the corresponding... 

A method for the estimation of the total alkaloids and of non-phenolic alkaloids (emetine fraction) is given in the British Pharmacopoeia, 1932, Addendum VI, which requires the drug to contain not less than 2 per cent, of alkaloids, of which at least 55 per cent, must be non-phenolic bases, calculated as emetine. The British Pharmacopoeia also gives an assay process for emetine in emetine bismuth iodide, the form in which the drug is chiefly used in medicine it is required to contain not less than 25 and not more than 28 per cent, of emetine. In the United States Pharmacopoeia, XIII, both Cephcelis Ipecacuanha and C. acuminata are recognised and must contain not less than 2 per cent, of ether-soluble alkaloids. 

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