In this paper, two new kinds of hydroxy aminimide were nanoscale synthesized utilizing Unsymmetrical dimethyl hydrazine (UDMH) and economical carboxylic acid methyl ester was analyzed through one pot reaction. The reaction conditions were examined and the best reaction temperature was 20 °C with the reaction time of 60 h, achieving a highest yield of 83.21% for the two aminimides. Structures of the final products are characterized by GC-MS, FT-IR and NMR. Then the thermal stability of the aminimide is tested and it is found that the decomposition temperature of one aminimide is 65.20 °C, which is better than any other aminimides used for the latent curing agent of epoxide resin.
The content of AP and Al in waste propellant and waste water produced by high pressure waterjet clearing HTPB propellant were determined according to some relative standard methods. The results show that the content of AP in the waste propellant with diameter less than 3mm drops from 69.5% to 35.28%, while the loss of Al and adhesives is slight; in the waste propellant with diameter larger than 3mm, the component content is close to normal charge with the increase in radial depth; the content of AP and Al in the waste water are 8368mg/L and 0.157mg/L respectively. Based on above results, the proper treatments of the wastes were chosen: the waste propellant can be used as auxiliary fuel for boilers after leaching AP out with the waste water; the waste water should be treated with biological methods to remove ammonia nitrogen and perchlorate in it.
Basing on the complexity and uncertainty of many risk factors which were presented in the solid rocket motor waterjet clearing system, according to operating procedures of the waterjet clearing system, the analytic hierarchy process was adopted to establish its safety evaluation index system, and then the gray comprehensive evaluation was used to evaluate the solid rocket motor waterjet clearing system security. The evaluation results indicate that the solid rocket motor waterjet clearing system's comprehensive evaluation value is 3.1126 and at a higher risk situation, thus there is need to strengthen the prevention and control of the risk factors in it; the comprehensive evaluation value of the waterjet clearing platform is 3.2417, which is higher than the overall comprehensive evaluation value, therefore it should be paid attention to in risk prevention and control; the evaluation result is in good agreement with the actual situation.
Abstract Energetic materials have been widely used in both military and civilian fields. The development of new high‐energy materials with improved performance and enhanced stability is critical for promoting future military and space applications. Recently, researchers in the field of energetic materials have paid significant attention to oxadiazole‐based energetic compounds, among which 1,3,4‐oxadiazole demonstrates moderate energy levels and better stability, owing to the absence of readily cleaved N−O bonds compared with other oxadiazole isomers, such as 1,2,4‐oxadiazole and 1,2,5‐oxadiazole. Therefore, 1,3,4‐oxadiazole is an exceptional explosophoric motif with an efficient compromise between energy and stability, and several outstanding energetic materials have been achieved based on the combination of 1,3,4‐oxadiazole units with various functional groups or rings, such as polynitrobenzene, furazan, pyrazole, and 1,3,4‐oxadiazole itself. This review provides an overview of the development of 1,3,4‐oxadiazole‐based energetic materials during the past few years, outlines their synthesis and energetic performance, and contrasts them with other conventional energetic materials. Owing to the convenience of the synthetic routes and their excellent energetic properties, energetic materials based on the 1,3,4‐oxadiazole skeleton may be considered as the next‐generation of high‐performance energetic materials specifically as heat‐resistant explosives or insensitive explosives.
The article introduces the constitution, inspection principles, functions and main technical parameters of optical fiber synthetic insulation automatic inspection system。 In the practice of the project, It shows that the system is able to execute the real time monitoring and management, dynamically observe the degradation of transmission performance, timely discover and predict the potential problems, improve the quality for maintenance and guarantee the safety and reliable operation of the optical fiber line.
A short and highly efficient route to deoxy-Melodorinol analogues has been developed.The key to the overall transformation is the use of an enantioselective Sharpless asymmetric dihydroxylation of an (Z,E)-dienoate to control the regioselectivity of the dihydroxylation reaction and a Mitsunobu elimination reaction to control the E-stereochemistry of the γ,δ-double bond.The highly efficient synthesis stereoselectively prepared four analogues in 3 steps from 4-substituted crotonaldehydes.
A short and highly efficient route to both enantiomers of muricatacin as well as the C-5-epimer has been developed. The key to the overall transformation is the highly regio- and enantioselective Sharpless asymmetric dihydroxylation of an (E,Z)-dienoate. The highly efficient stereoselective synthesis prepares (−)-muricatacin in seven steps and 66% overall yield.
A basket-shaped C56H38 hydrocarbon (3) possessing a 30-carbon difluorenonaphthacenyl core that can be mapped onto the surface of C78 was synthesized from 4-bromo-1-indanone. The first stage of the synthesis involved the preparation of tetraketone 10 as a key intermediate. The use of cascade cyclization reactions of benzannulated enyne−allenes as key features in the next stage of the synthetic sequence provides an efficient route to 3 from 4-bromo-1-indanone in 12 steps. The all-cis relationship among the methyl groups and the methine hydrogens causes the two benzofluorenyl units in 3 to be in an essentially perpendicular orientation to each other. Hydrocarbon 3 and its derivatives could serve as attractive precursors leading to a geodesic C68H26 end-cap template for carbon [6,6]nanotubes.
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