TPD of ammonia from H-ZSM-5 zeolites deactivated during coupled methanol hydrocarbon cracking (CMHC)

The deactivation of H-ZSM-5 zeolite samples during coupled methanol/hydrocarbon cracking (CMHC) with n-butane as feed has been investigated in two different reaction modes (with intermediate regeneration and without regeneration). TPDA was used to characterize strong Brönsted acidity of fresh, regenerated and steamed H-ZSM-5 zeolite. The prevention of dealumination by blocking the acid centers with carbonaceous products could be proved, but the conversion rate of n-butane and the olefin selectivity declined drastically with increasing coking rate. H-ZSM-5 - / - - ( -). , - H-ZSM-5. - , , - - .     

Synthesis of Water-Soluble “Molecular Tweezers” on the Basis of 4,4'-Diaminodiphenyl Sulfone and Monosaccharides

Novel water-soluble acyclic host molecules with a molecular tweezer topology were synthesized on the basis of 4,4'-diaminodiphenyl sulfone by the Schiff reaction with monosaccharides: D-()glucose, D-glucuronic acid -lactone, and D-gluconic acid -lactone. Optimal conditions for preparing each type of the receptor molecules were chosen.     

Abnormally high fractal dimension of silica surfaces measured by adsorption of aliphatic alcohols

Factors leading to abnormally high fractal dimension D of silica surfaces measured by adsorption of aliphatic alcohols have been analyzed. , D .     

Investigations of 2,3′-biquinolyl. 7. Thiolation of 1-alkyl-3-(2-quinolyl)quinolinium halides

Thiolation of 1-alkyl-3-(2-quinolyl)quinolinium halides by a mixture of sulfur with KOH in DMF leads to formation of 1-alkyl-1,4-dihydro-2,3-biquinolyl-4-thiones, rearrangement of which in boiling ethylene glycol makes it possible to obtain 4-alkylthio-2,3-biquinolyls.     

Oscillatory reactions of sakhalin oil oxidation

After light irradiation of oil films on water surface the autoxidation process has been found to be of nonsteady auto-oscillatory character, which can be observed in rate oscillations of O₂ absorption. Also recorded have been intensity oscillations of the EPR signal from the radical counter added into an oil sample. Complex dynamics of autoxidation can be due to an autocatalytic process involving the participation of peroxides accumulated in oil during photooxidation., , , , O₂. , , . , , .     

The feedback controlled chemical reactor, I. General theoretical description

Some general dependences of the injection volumes of reaction components on time have been derived for the feedback controlled chemical reactor. .     

Alkylation of p-substituted phenols by heteropoly acids

Liquid-phase alkylation of p-tert-butylphenol (TBP) and p-cresol by olefins and benzyl chloride in the presence of solid heteropoly acids (HPA) H₃PW₁₂O₄₀ and 25% H₃PW₁₂O₄₀/SiO₂ at 100–150°C provides high yields of mono- and disubstituted products. HPAs are more active than H₂SO₄, easily separated from the reaction mixture and can be used repeatedly. -- () - () H₃PW₁₂O₄₀ 25% H₃PW₁₂O₄₀/SiO₂ 100–150°C - - . , H₂SO₄, - - .     

Transformation of batridene

Transformations of 1,1,6,6,7,7-hexahydroxy-3,3-dimethyl-5,5-diisopropyl-2,2-dinaphthylidene-8,8-dibarbituric acid (batridene) in DMSO are studied.     

Some observations of HZSM-5 zeolite dehydroxylation

The dehydroxylation of 3610 cm^–1 OH groups in HZSM-5 zeolite and in two Ni and Mo modified catalysts containing the same zeolite has been studied at 673 K. The presence of water vapor is a necessary condition of dehydroxylation, the extent of which depends on the number and duration of breaks consisting in cooling to room temperature and reheating to 673 K with evacuation. OH HZSM-5, Ni Mo- , 3610 cm^–1, 673 . , 673 .     

Investigations of 2,3′-biquinolyl. 9. Reaction of 1′,4′-dihydro-2,3′-biquinolyl with organolithium compounds

The 1,4-dihydro-2,3-biquinolyl reacts with organolithium compounds to form the mixture of 4-R-1,4-dihydro-2,3-biquinolyls and 2-R-1,2-dihydro-2,3-biquinolyls in the ratio analogous to the conversion in the series of 2,3-biquinolyl. The utilization of the complex, the organolithium compound-TMEDA, in this process leads, after treatment of the reaction mixture with water, exclusively to 2-R-1,2-dihydro-2,3-biquinolyls. Treatment with methyl iodide leads to 1-methyl-2-R-1,2-dihydro-2,3-biquinolyls.     

Kinetics of C2H4 polymerization on reduced V2O5/Al2O3 catalyst

Kinetic study of C₂H₄ polymerization on reduced V₂O₅/Al₂O₃ catalysts revealed that the rate equation can be expressed as V=k exp (-Y) K_aP_E/(1+K_aP_E) in the temperature range of –20 to 70°C. The deactivation constant, , was found to have a close relation with the yield and molecular weight of the polymer. C₂H₄ V₂O₅/Al₂O₃ –20 +70°C : V_p=k·exp(-Y_p)·K_aP_e/(1+K_aP_e). .     

Study of CO and H2 sorption on supported bimetallic Pd?Pb catalysts

With increasing the lead content both CO and hydrogen sorption drop considerably. The influence of lead can be observed starting from a concentration of 0.5%. This may indicate that the surface is enriched in lead atoms.

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CO, H₂. , 0,5%. .

     

Chemisorptive characterization of Mn2+ cation effects on fused iron-catalysts

Volumetric and pulse chemisorptions of carbon monoxide (CO) have been developed to characterize effects of Mn²⁺ cations on an industrial doubly promoted fused iron catalyst. Addition of Mn²⁺ cations induces an increase in Fe dispersity, Fe electronic density and stability of the Mn²⁺-containing iron catalyst, where the same increase is observed by XPS and SEM. These effects explain why the activity of Mn²⁺-containing iron catalysts is improved. Mn²⁺ , . Mn²⁺ Fe, Fe , XPS SEM. . Mn²⁺ .