Regioselective synthesis of functional tellanes from tellurium tetrahalides and 1-octene

Proceeding from TeCl₄ and 1-octene a regioselective method was developed of the synthesis of trichloro(2-chlorooctyl)tellane. At adding methanol to this compound chlorine was easily replaced at room temperature by a methoxy group affording trichloro(2-methoxyoctyl)tellane. The reaction of TeBr₄ with 1-octene in methanol resulted in tribromo(2-methoxyoctyl)tellane. A reduction of trichloro- and tribromo(2-methoxyoctyl)tellanes occurs the most selectively in the system NaBH4–water–THF giving 1,2-bis(2-methoxyoctyl)ditellane. The reactions are characterized by a high selectivity and quantitative yields of the products.     

Production of semicokes with increased content of nitrogen by cocarbonization of various cakes with polyacrilonitrile

Pyrolysis of polyacrylonitrile mixtures with coal-tar pitch, pitch from heavy tar in ethylene production, and poly(vinyl chloride), a precursor of poly(vinyl chloride) pitch, was subjected to a comparative analysis. The content of various forms of nitrogen in the carbon materials obtained was determined.     

Incorporating ergonomic risks into assembly line balancing

In manufacturing, control of ergonomic risks at manual workplaces is a necessity commanded by legislation, care for health of workers and economic considerations. Methods for estimating ergonomic risks of workplaces are integrated into production routines at most firms that use the assembly-type of production. Assembly line re-balancing, i.e., re-assignment of tasks to workers, is an effective and, in case that no additional workstations are required, inexpensive method to reduce ergonomic risks. In our article, we show that even though most ergonomic risk estimation methods involve nonlinear functions, they can be integrated into assembly line balancing techniques at low additional computational cost. Our computational experiments indicate that re-balancing often leads to a substantial mitigation of ergonomic risks.     

Synthesis of vinylsulfonyl(halo)pyridines and their reactions with binucleophilic reagents

Oxidation of vinylthio(halo)pyridines with 30–33% hydrogen peroxide solution in acetic anhydride at 20–25°C furnished vinylsulfonyl(halo)pyridines. Nucleophilic addition reactions of 2-amino-1-ethanethio hydrochloride and thiosemicarbazide to the multiple bonds of vinylsulfonyl(halo)pyridines were performed.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1705–1708.Original Russian Text Copyright © 2004 by Amosova, Gavrilova.     

Reactions of 1,2,4,5-Tetrafluoro-3,6-bis(vinylsulfonyl)benzene with Cyclic Amines

Reactions of 1,2,4,5-tetrafluoro-3,6-bis(vinylsulfonyl)benzene with pyrrolidine, piperidine, and morpholine lead to formation of different products, depending mainly on the reactant ratio. In the presence of 2 equiv of cyclic amine, adducts at both vinylsulfonyl groups are formed, while in reactions with 4 equiv of cyclic amine, the addition at the double bonds is accompanied by nucleophilic replacement of one or two fluorine atoms in the benzene ring.     

Stereo specificity of the direct13C-1H spin-spin coupling constants of the vinylthio group in alkyl vinyl sulfides

The direct ¹³ C-¹ H coupling constants in the vinylthio group are stereospecific and depend on the conformation of the vinyl sulfide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 461–464, February, 1990.