Synthesis of 4,5-Dichloroisothiazole-3-carboxylic Acid Amides and Esters

Previously unknown 4,5-dichloroisothiazole-3-carboxylic acid amides and esters were synthesized by reactions of 4,5-dichloroisothiazole-3-carbonyl chloride with ammonia, heterocyclic and aromatic amines, and functionally substituted alcohols and phenols.     

Adjustment of the burning rate of a composite propellant with regard to its temperature sensitivity

Systematic multifactor experiments aimed at studying the regularities of the adjustment of the burning rate of composite propellants, especially its temperature sensitivity, were performed. It was established that, in contrast to the pressure dependence of the burning rate, which is largely determined by the properties of the base subsystem of components, its temperature sensitivity is influenced by the flame characteristics as well, more specifically, by the properties of the filler particles dispersed into the gas phase, a slowly burning component.     

Thermal stability of the burning of the base subsystem of components of a composite propellant

The problem of the thermal stability of the base subsystem of components of a composite solid propellant with respect to the introduction of heat-absorbing agents, inhibitors, and burning rate catalysts was considered. It was demonstrated that the response of the base subsystem to the introduction in it of additives is equivalent to a change in the initial temperature of the propellant, i.e., is determined by its burning rate temperature sensitivity. The competition of the fuel components for oxidative species and the role of this phenomenon in the formation of the structure of the combustion wave were examined. Extensive experimental data on the effect of heterogeneous fillers of various natures on the burning rate of the composite system were obtained.     

Synthesis of 4,5-dichloro-3-cyanoisothiazole and its functional derivatives

By treating with phosphorus pentoxide the 4,5-dichloroisothiazole-3-carboxamide 4,5-dichloro-3-cyanoisothiazole was synthesized whose reactions with piperidine, phenyl-and benzylthiols occurred with replacement of the chlorine atom in the position 5 by the residue of the corresponding nucleophile. Reactions with sodium thiobytylate and also with sodium methylate in methanol led to the formation both of the products of chlorine substitution by BuS or MeO groups respectively and of addition products of methanol to the cyano group. The reaction of butanethiol with cyanoisothiazole in 2-propanol in the presence of sodium 2-propylate was more selective and resulted in the replacement of the chlorine atom in the position 5 by the residue of the butanethiol.     

Emission Properties of Laser Plasma Excited on Molecular-Cluster Carbon Dioxide Jets

Technical Physics - We report on the results of investigation of a gas-jet laser-plasma source of extreme ultraviolet radiation based on a conical supersonic nozzle. As a target, we used...     

Synthesis of 5-alkyl(aryl)sulfanyl-4-chloro-3-trichloromethyl-1,2-thiazoles and 5-Alkyl(aryl)sulfanyl-4-chloro-1,2-thiazole-3-carboxylic acids

Butane-, phenylmethane-, and benzenethiols reacted with 4,5-dichloro-3-trichloromethyl-1,2-thiazole in the presence of sodium ethoxide to give the corresponding 5-alkyl(aryl)sulfanyl-4-chloro-3-trichloromethyl-1,2-thiazoles. The reaction of 4,5-dichloro-1,2-thiazole-3-carboxylic acid with the same thiols under similar conditions resulted in the formation of sodium 4,5-dichloro-1,2-thiazole-3-carboxylate, while in the presence of pyridine 5-alkyl(aryl)sulfanyl-4-chloro-1,2-thiazole-3-carboxylic acids were obtained.     

Influence of Thermal Annealing on the Properties of Multilayer Mo/Be Mirrors

Technical Physics - The influence of thermal action on X-ray optics performance and structure of films and transition regions in multilayer Mo/Be mirrors optimized for a reflection maximum in the...     

Emission Spectra of Molecular Gases N2 and CO2 in the Range of 3–20 nm upon Pulsed Laser Excitation of Various Gas-Jet Targets

Optics and Spectroscopy - Results of investigation of emission spectra of N2 and CO2 upon pulsed laser excitation are presented. The spectral range between 3 and 20 nm was studied using a Nd:YAG...     

Synthesis of Some Terpene-Alcohol, Sterol, and Plant Phenol Esters of 4,5-Dichloroisothiazol-3-carboxylic Acid

Previously unknown esters 1b-14b were prepared by reaction of cetyl alcohol 1a, terpene alcohols 2a-6a, sterols 7a-11a, and plant phenols 12a-14a with 4,5-dichloroisothiazol-3-carboxylic acid chloride.     

Model of the heterogeneous catalyst of the combustion of condensed systems

A model of the heterogeneous catalysis of the combustion of condensed systems based on an analysis of local changes in the burning velocity of the condensed phase of the propellant was developed. The model expresses the catalyst efficiency through the concentration and particle size of the catalyst and the uncatalyzed propellant burning velocity. Two experimentally determined parameters were introduced to characterize the effect of the chemical properties of the propellant system. The catalysis efficiency was demonstrated to tend to finite limits at d → 0 and U ₀ → 0. This model for the first time made it possible to correctly describe a wide variety of experimentally observed regularities.