Synthesis of esters of oxathiinecarboxylic and dithiinecarboxylic acids and their derivatives

Conclusions The reaction of the methyl ester of 3-phenyl-3-chloro-2-ketopropionic acid with mercaptoethanol and 1,2-dithioglycol gives derivatives of oxathiine and dithiine. The oxidation of these products gives the corresponding sulfones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1670–1672, July, 1988.     

μSR study of intermediate heavy fermion system CeRuSi2

We have studied the magnetic spinel (Zn)[Fe₂]O₄ (T_ N\approx10.5\ K) and the non‐magnetic spinels (Zn)[Al₂]O₄, (Zn)[Ga₂]O₄, (Zn)[ZnTi]O₄ and (Zn)[ZnSn]O₄ , both with surface and decay channel muons. In (Zn)[Fe₂]O₄ the relaxation rate increases monotonically from room temperature down, typical for a paramagnet. Around 30 K, an additional, stronger damped signal appears which is the signature of short‐range ordered (SRO) regions. Their total volume fraction increases drastically towards T_ N (reaching 75%) and astonishingly, continues to be present also below T_ N where the rest of the material has become long‐range ordered. Longitudinal field μSR proves the SRO to be dynamic. In (Zn)[Al₂]O₄ and (Zn)[Ga₂]O₄ muon depolarization is caused solely by ²⁷Al or ^69,71Ga nuclear dipoles. In the inverse spinel (Zn)[ZnTi]O₄, half of the implanted muons depolarize rapidly (\lambda\approx 3μs^-1 at room temperature). This, together with repolarization behavior in longitudinal fields indicates that the muon in (Zn)[ZnTi]O₄ undergoes a chemical reaction after implantation forming muonium. The fact that no such muonium formation occurred in another inverse spinel ( (Zn)[ZnSn]O₄) means that the presence of muonium is not connected to the inverse structure but rather due to the presence of Ti which offers two d‐electrons to participate in the chemical bonding. Additional evidence for d‐electron participation is provided by ⁶⁷Zn‐Mössbauer data which indicate unusual electron densities at the ⁶⁷Zn nuclei only in (Zn)[ZnTi]O₄.     

A numerical scheme for the solution of axisymmetric radiative transfer problems in irregular domains filled by media with opaque and transparent diffuse and specular boundaries

This paper presents a new numerical scheme of the discrete ordinates method for the solution of axisymmetric radiative transfer problems in irregular domains filled by media with opaque and transparent diffuse and specular (Fresnel) boundaries and interfaces. New test problems of radiative transfer, which describe radiative transfer in domains with Fresnel interfaces, are proposed in this paper. These problems admit analytic solutions and can be used as benchmark ones. The proposed scheme is applied to the solution of the problems. Numerical results show that the presence of Fresnel interfaces leads to an appreciably larger error in numerical solution. This is connected with the “discontinuity” of the Fresnel reflectivity, which, through numerical diffusion, leads to the distortion of numerical solution. Modification of the scheme allows to reduce the numerical error.     

Synthesis of Tricyclic Diesters from 8-Acetoxytricyclodec-3-ene Monoester

Tricyclic diesters were synthesized in yields of 70.4–90.8% by the addition of С₂–С₅ monobasic carboxylic acids to tricyclo[5.2.1.0^2,6]dec-3-еn-8-yl acetate in the presence of a BF₃·OEt₂ catalyst. One of the synthesized diesters, tricyclodec-3,8-diyl diacetate, has a pleasant smell with a citrus scent and can be used in different perfume compositions as a flavoring.     

Intermediate oxygen-containing compounds in oxidative condensation of methane over sodium-manganese catalysts

CH₂O conversion over sodium-manganese oxide and oxychloride catalysts in methane dehydrodimerization have been studied under unsteady-state conditions at high temperatures (600–750 °C). It has been established that formaldehyde conversions produce deep oxidation (CO, CO₂), condensation (C₂H₄, C₂H₆) and methanation products through CH₃O^– formation and decomposition.

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(600–750°C) CH₂O - . , (CO, CO₂) (C₂H₄, C₂H₆), , CH₃O^–.

     

Dichloromethyl tert-butyl ketone in the Darzens reaction

The condensation of dichloromethyl tert-butyl ketone (1) with benzaldehyde, para-bromobenzaldehyde, and 2,4-dichlorobenzaldehyde under conditions for the Darzens reaction gives 1-aryl-1-chloro-4,4-dimethyl-2,3-pentanediones (2–4). In the case of nitrobenzaldehydes, the reaction products are 1-aryl-2-chloro-1,2-epoxy-4,4-dimethylpentanones (5 and 6), which isomerize to -chloroketones (7 and 8) upon prolonged storage or heating at reflux in benzene.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 438–441, February, 1992.