Synthesis of Novel Macrocyclic Ligands Containing Phosphoryl and Aminoacetal Fragments

Abstract

A method for the synthesis of novel phosphorylated aminoacetals was developed. The latter are involved in Mannich reaction as amine component with calix[4]resorcinol and formaldehyde to form tetrasubstituted macrocycles containing four acetal groups and four phosphonate (phosphine oxide) fragments on the “upper” rim of molecule with high yields.     

The effect of the nature of a modifying additive (Pt,Zn, Ga) on the activity of oxide and zeolite catalysts in ethane dehydrogenation and aromatization

The catalytic properties of Pt, Zn, and Ga deposited on supports of various natures (Al₂O₃, SiO₂, NaZSM, and HZSM) in the dehydrogenation and aromatization of ethane were investigated. Pt-containing catalysts are the most active in the conversion of ethane: the selectivity with respect to ethylene is 25–87 % depending on the nature of the support. In the presence of Zn- and Ga-containing catalysts the yield of ethylene is 2–3 times lower than with Pt-catalysts. With HZSM modified by Pt, Zn, or Ga aromatic hydrocarbons (ArH) and methane are the main products of ethane transformation. Ga/HZSM is the most efficient catalyst of the aromatization of ethane under the conditions studied (550 °C, 120 h^–1).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 606–609, April, 1994.     

Alkylation of benzene by propane over zeolite-containing pentasil-alumina compositions and dealuminated pentasils

The alkylation of benzene by propane over pentasil-aluminum compositions (HTsVM--Al₂O₃) has been studied for a wide range of compositions and also over dealuminated and dehydroxylated samples. It has been established that Al₂O₃ plays little if any part in this reaction. As the proportion of HTsVM in the composition is increased the yield of alkyaromatic hydrocarbon increases, reaching a maximum (36%) for pure HTsVM. Dealumination and dehydroxylation of the HTsVM led to a significant reduction in the yield of alkylation products. It was concluded the Brønsted acid centers of the zeolite are responsible for bringing about the alkylation of benzene by the lower alkanes.DeceasedN. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2708–2712, December, 1992.     

The effect of an intermetallic hydrogen acceptor on catalytic aromatization of propane

The effect of the intermetallic compound Zr₂Fe as a hydrogen acceptor in the aromatization of propane in the presence of a zeolite catalyst has been investigated. High-silica, pentasil-type zeolite ZVM was modified by Zn, Ga, or Pt. The intermetallic compound was found to remove hydrogen formed during aromatization, resulting in a 2-to 5-fold increase in the yields of aromatics and in a marked increase in selectivity for aromatization. The magnitude of this effect is shown to be dependent on the catalyst composition.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 61–63, January, 1993.     

Transformations of cyclohexane and benzene on the bimetallic Ru-Pt oxide catalysts

The bimetallic Ru-Pt/Al₂O₃ catalysts with an overall metal content of 1 wt. % and Pt: Ru weight ratios from 1: 3 to 3: 1 were studied. The catalytic activity for cyclohexane and benzene transformations, including hydrogenation, hydrogenolysis, and skeletal isomerization of the initial substrates and products of intermediate transformations, was studied at temperatures 180–350 °C and H₂ pressures from 1.0 to 5.0 MPa. The maximum yield of n-hexane from cyclohexane and benzene was obtained on the catalysts with a ruthenium content of 0.75–1.0%, being ∼29–30 wt.% at 40% selectivity. The selectivity to form n-hexane decreases with an increase in the cyclohexane conversion and is almost independent of the composition of the Ru-Pt system. On the catalysts under study, benzene is converted to the same products but at temperatures by 60 °C lower as compared to cyclohexane conversion. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 633–637, April, 2006.