Methyl phenyl silicone

The diacetate was judged to be virtually pure by the submitters on the basis of a gas chromatographic analysis carried out at 150° using a glass column packed with 3% OV 17 (1 1 methyl-phenyl silicone) supported on 70-80 mesh Chromosorb W. 

The sample thus obtained is 94-97% pure by capillary GC analysis using a 25-m 5% methyl phenyl silicone capillary column. This material gave the following elemental analysis Anal. Calcd for Ci2 15 0 C, 76.15 H, 7.99 N, 7.40. Found C, 75.49 H, 8.15 N, 7.31. 

Silicone. Silicone elastomers have a siloxy backbone with methyl, vinyl, and phenyl groups attached. The elastomers are designated by their chemical composition, as follows methyl silicone (MQ), methyl vinyl silicone (VMQ), methyl phenyl silicone (PMQ), methyl phenyl vinyl silicone (PVMQ), and fluorovinyl methyl silicone (FVMQ). 

Conventional high pressure NICI spectra were obtained using a Hewlett-Packard 5985B quadrupole GC/MS, as described previously (1). Methane was used as the Cl reagent gas and was maintained in the source at 0.2-0.4 torr as measured through the direct inlet with a thermocouple gauge. A 200 eV electron beam was used to ionize the Cl gas, and the entire source was maintained at a temperature of 200° C. Samples were introduced into the spectrometer via the gas chromatograph which was equipped with a 25 meter fused silica capillary column directly interfaced with the ion source. For all experiments, a column coated with bonded 5% methyl phenyl silicon stationary phase, (Quadrex, Inc.) was used and helium was employed as the carrier gas at a head pressure of 20 lbs. Molecular sieve/silica gel traps were used to remove water and impurities from the carrier gas. 

Ethyl phenyl silicone is another alkyl-aryl silicone which may be made either from ethylphenyldichlorosilane41 or by cocondensation of mixed ethyl and phenyl chlorosilanes. The cross-linked ethyl phenyl silicone resins have good dielectric and mechanical properties, but their maximum service temperatures in air are somewhat lower than those for methyl phenyl silicone, being limited to about 250° C. for... 

Similarly, ordinary handling of the methyl and methyl phenyl silicone polymers of all the types described and of their intermediate condensation products as well has not resulted in a single symptom of toxicity. The oils appear to be bland and to cause no skin disorders the resins are sticky but are readily washed off the skin with hydrocarbon solvents. The absorption of oil and resin through the skin seems to be inconsequential. 

Propoxyphene Hydrochloride, Aspirin and Caffeine capsules (for Propoxyphene and Caffeine 0.6 M X 3 mm I.D. 3% Methyl Phenyl Silicone liquid/80-10 mesh siliceous earth Nitrogen 175 FID n-Tricosane USP (24, p. 1423)... 

The type of analysis utilized to determine the composition of a pyrolysate is important because only a certain group of compounds can be seen in one type of analysis. The identification of more volatile compounds found in cellulose pyrolysate can be done very conveniently by on-line Py-GC/MS analysis. The TIC traces of cellulose pyrolysate obtained at 590° C and separated on a Carbowax or on a methyl-phenyl silicone type column were already given in Section 5.2 (Figures 5.2,10, 5.2.11 and 5.2.13). As indicated in Section 5.2, in these chromatograms compounds such as formaldehyde, methanol, or CO were not seen because the mass spectrometer used for the analysis had the mass range detection with a low cut-off at m/z = 32. 

In a number of investigations the methyl phenyl silicone OV-17 has successfully been used for separation and also for quantitative determinations of tropane alkaloids in pharmaceutical preparations9 10 11 12 13 14 15. 

Carbamate pesticides in environmental samples have long been determined by GC, using packed columns. Methyl silicones (SE-30, OV-101), ° methyl phenyl silicones (OV-17), and fluoropropylsilicones (QF-1) are among the stationary phases most frequently used for this... 

Chem. Descrip. Methyl phenyl silicone resin aq. emulsion Uses Binderfor highly pigmented and gloss paints, clear varnishes, low-VOC coatings food-contact coatings Features Dries to tack-free finish at R.T. rec. for blending with water-based org. resins high shear resist. 

Chem. Descrip. Methyl phenyl silicone resin sol n. in xylene (45%)/bu-... 

Chem. Descrip. Methyl phenyl silicone resin in xylene Uses Silicone for use in heat-resist, coatings for appliances, engines, mufflers, furnaces, stacks, heat exchangers food-contact coatings Features Dries soft, flexible, and tack-free at R.T. gains solv. resist, at 260 C, maintains flexibility, film integrity beyond 650 C Regulatory FDA 21 CFR 175.300... 

Fig. 5. Swelling of silicone rubber by solvents (493). A, fluorosilicones (methyl trifluoro-propyl silicones) B, dimethylsUicone C, methyl(phenyl)silicone.

It was established that catalysts present in CNTs also strongly affect thermal stability of CNTs in air. Active metal particles present in the nanotube samples catalyze carbon oxidation, so the amount of metal impurity in the sample can have a considerable influence on the thermal stability. For example, Zhou et al. (2001) found that if the oxidation of as-synthesized CNTs, which contained traces of catalyst (Fe), was quite rapid and homogeneous at 350 °C due to the catalytic effect, the purified CNTs had negligible weight loss, even after annealing at 460 °C. Furthermore, the presence of Fe obscured the dependence of oxidative stability on tube diameter as discussed earlier. After removing the Fe, all tubes were more appropriate for observing diameter-dependent oxidative stability. Li et al. (2011) have found that the presence of cobalt catalysts dramatically decreases the thermal stability of CNT/peroxide-curable methyl phenyl silicone gum composites as well. This means that the presence of uncontrolled impurities in CNTs can be one of the reasons for reduced reproducibility of sensor parameters. This conclusion is confirmed by results obtained by Boccaleri et al. (2006) and Zhou et al. (2001) (see Fig. 21.5). 

In GC, there is not much variance in the chemical composition of the mobile carrier phase, which is usually He gas. Therefore, chemical composition of liquid-phase molecules on the column and the temperature change during separation determine the effectiveness of separation. Combinations of chemical structures in the liquid-phase chains are common, such as the use of different ratios of methyl/phenyl silicons. The retention time, i.e., time necessary for a compound to pass through the column increases with the volatility of the compounds. To achieve better separation, a temperature gradient is applied that reduces peak broadening due to diffusion. 

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