Sulfur temperature effects

In this study, the dipole moments at 298 K and the corresponding temperature coefficient of PDTC are calculated in the RIS approximation. The results are compared to the values determined by experiment. The results indicate that an extra stabilization energy of about 3.8 kj mol-1 must be added to these gauche states relative to trans state. This provides evidence of a large attractive sulfur gauche effect in the polysulfides, about equal in magnitude to that found for the analogous POM. 

Treatment of 2-benzoylbenzoic acid with concentrated sulfuric acid effects cyclodehydration to anthraquinone, a pale-yellow, high-melting compound of great stability. Because anthraquinone can be sulfonated only under forcing conditions, a high temperature can be used to shorten the reaction time without loss in yield of product the conditions are so adjusted that anthraquinone separates from the hot solution in crystalline form favoring rapid drying. 

The results of leaching Illinois No. 6 coal with different alkaline solutions followed by acid treatment are shown in Table II. In each leaching experiment 15 g. of coal was leached with 120 ml. of alkaline solution at 250°C for 1 hr. In some experiments the alkali-leached coal was washed with hydrochloric acid, and in other experiments the coal was washed with sulfuric acid. When hydrochloric acid was employed, the acid washing step was conducted at the boiling point and the final water washing step at room temperature. However, when sulfuric acid was used, the washing steps were conducted at various temperatures to study the temperature effect. 

Formylation of amines and alcohols. Behai,8 discoverer of the reagent, found that it reacts unidirectionally with simple alcohols to produce alkyl formates free from acetates. Hurd et al. J found that acetic-formic anhydride (prepared from formic acid and ketene) reacts quantitatively with aniline to give formanilide. Another study10 established that acetic-formic anhydride mixes endothermally with 2-nitro-2-methyl-l-propanol, exothermally with 2-nitro-2-methyl-l,3-propanediol, and displays no appreciable temperature effect with either 2-nitro-l-butanol or tris-(hydroxymethyl)-nitromethane. Formic esters are favored by avoiding a high reaction temperature and by not using sulfuric acid as catalyst. The mixed anhydride has been used for the preparation of formyl fluoride.11... 

Add with a pipet a 0.2-mL aliquot of each of the filtrates into a clean, dry test tube, and at 30-s intervals add 1.00 mL enzyme reagent. Immediately place in a 37°C water bath. (Reactions may be run for 45 minutes at room temperature with some loss in sensitivity.) Run duplicate aliquots of the unknown filtrate. After exactly 30 minutes, remove the tubes one at a time (30-s intervals) and add 50 mL 3 M H2S04. The sulfuric acid effectively stops the enzyme reaction. 

Liquid sulfur temperature. As previously mentioned, the best temperature for sulfur spraying is approximately 310 °F. Tests have shown that as the temperature decreases, the effectiveness of the coating is reduced. Temperatures up to 317°F are acceptable but above 318°F, the sulfur viscosity is so great that good sulfur atomization is virtually impossible. 

The S—A-S mixtures should be prepared and mixed while the materials are between about 260 and 320°F. The former represents the melting (solidification) point plus a tolerance to avoid sulfur structuring effects, and the latter is the temperature above which sulfur undergoes an abrupt and very large increase in viscosity as shown in Figure 2. Although these viscosity changes are perfectly reversible (2), they do adversely affect the workability of the mix above about 325°F. However, as will be shown later, acceptable mixes were prepared at sulfur temperatures... 

Comparative study of the sulfur loss in the xerogel and aerogel sulfated zirconia calcined at different temperatures effect on n-hexane isomerization... 

Fig. 1.20 Steady-state galvanostatic polarization curves for the oxidation of 1.0 M methanol on Pt/Sn electrodes in 0.5 M sulfuric acid at room temperature. Effect of perfiuoroalkanesulfonic acid additives upon ease of methanol electrooxidation.

Sulfide stress cracking (SSCC) has special importance in the gas and oil industry, as the materials being processed there (natural gas and crude oil) often contain a considerable amount of hydrogen sulfide. SSCC is a low-temperature effect of H2S in an aqueous environment, and sulfidation is the term used for high-temperature (>250°C) sulfur corrosion. In gas pipelines, if the gas is sweet... 

Morrison, N. J., Porter, M. (1983). Temperature effects on structure and properties during vulcanization and service of sulfur-crosslinked rubbers, Plast. Rubber Proc. 

Mejri 1, Younes M K, Ghorbel A, Eloy P, Gaigneaux E M (2006) Comparative study of the sulfur loss in the xerogel and aerogel sulfated zirconia calcined at different temperatures effect on n-hexane ismnerizatimi. Stud Surf Sci Catal 162 953-960... 

Choi JS, Partridge WP, Pihl JA, Daw CS (2008) Sulfur and temperature effects on the spatial distribution of reactions inside a lean NOx trap and resulting changes in global performance. Catal. Today 136 173-182... 

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