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991.
The relationship between detonation velocity and the elemental composition of components of aluminized explosives are assessed through quantitative structure-property relationship (QSPR). Here, two new reliable, simple models are proposed for estimating aluminized explosives detonation heat and velocity based on molecular structure by applying QSPR. In this methodology it is assumed that these two detonation parameters can be presented as a function of elemental composition, density and several structural parameters. This new correlation of heat detonation has determination coefficient of 0.930, root mean square deviation (RMSD) of 324.4 and average absolute deviation (AAD) of 446kJ · kg–1 for 36 aluminized explosives with different molecular structures as the training set. The predictive power of this new correlation is checked through a cross validation method. Statistical parameters reveal relatively good result for this correlation. Also, the determination coefficient of detonation velocity for the other new model is 0.960 and it has 151.1 (RMSD) and 107.9 m · s–1 (AAD) for 42 aluminized explosives with different molecular structures as training set. Reliability and validity of new correlation investigated (Q2Ext = 0.948, Q2LOO = 0.938, and Q2LMO = 0.937). The good ability of this new model for prediction detonation velocity of aluminized explosives are confirmed. 相似文献
992.
A convenient synthesis of some pyranocoumarins was described via a one‐pot, three‐component reaction of 4‐hydroxyxoumarin, malononitrile and different aromatic aldehydes in the presence of sodium tungstate. This is the first application of sodium tungstate as non‐oxidative catalyst in organic reactions. Simple operation, use of readily available starting materials, good to excellent yields and short reaction times are the advantages of this method for the synthesis of these biologically important products. 相似文献
993.
Vaezeh Fathi Sorour Ramezanpour Saeed Balalaie Frank Rominger Hamid Reza Bijanzadeh 《Helvetica chimica acta》2014,97(12):1630-1637
New hydrazinyl pseudo‐peptides have been obtained from Ugi four‐component reaction (4CR). The 5‐hydrazinyl‐5‐oxopentanoic acids used as starting materials were prepared by the reaction of hydrazides with anhydrides. Mild reaction conditions, high atom economy, bond‐forming efficiency, and easy workup are advantages of this approach. The products have four amide bonds and high potential for H‐bonding. 相似文献
994.
Majid Rafipoor Farhad Salimi Khosrow Jarrahian Seyyed Saeed Ghorashi 《Journal of Dispersion Science and Technology》2014,35(1):56-63
In this research, polyacrylamide-based gels were made at 25°C and aged in an oven at 90°C for 24 hours. The bottle testing results indicated that gel composed of 15000 ppm partially hydrolyzed polyacrylamide (PHPA) and 2500 ppm chromium(III) acetate exhibited an acceptable strength. The strain sweep test results showed that elastic modulus is fixed on 6 Pa below strain of 100%. According to frequency test results, linear viscoelasticity region was observed at the frequency limits from 0.1 to 10 s?1. Moreover, elastic modulus decreased from 8 Pa at 25°C to 4 Pa at 90°C. Furthermore, gelation time for gelant with the same composition was obtained (14, 13, and 20 minutes) in sequence. 相似文献
995.
A solvent‐free reaction between urea/thiourea, dimedone and aromatic aldehydes in the presence of catalytic amounts of zirconium (IV) oxychloride octahydrate (ZrOCl2.8H2O) as a powerfull Lewis acid leads to octahydroquinazolinone/thione derivatives in good yields. This method has advantages such as avoidance of the organic solvents, production of pure products without any by‐product, short reaction times and simple operation. 相似文献
996.
In this study, we have synthesized 1‐(4,6‐disubstitutedpyrimidin‐2‐yl)‐3‐(3,5‐dinitrobenzoyl)‐thiourea derivatives ( 1a , 1b , 1c , 1d , 1e , 1f , 1g , 1h ) and N‐[(2Z)‐3‐(4,6‐disubstitutedpyrimidin‐2‐yl)‐4‐phenyl‐1,3‐thiazol‐2(3H)‐ylidene]‐3, 5‐dinitrobenzamide ( 2a‐2h ) analogues and characterized by IR spectroscopy, NMR spectroscopy, elemental analysis, and single crystal X‐ray diffraction data. The compounds ( 2a‐2h ) were screened for antimicrobial activity against Gram positive, Gram negative, and fungal species. The results of antimicrobial study indicated that compounds showed most potential and appreciable antibacterial and antifungal activities. 相似文献
997.
The article describes ionic liquids [bmim][NO3] in the presence of 30% mol CuI as efficient media for the domino Knoevenagel–hetero–Diels–Alder reaction of o-propargyloxy benzaldehydes as unactivated terminal alkynes with some active methylene compounds. Short reaction time, easy workup, good to excellent yields, and mild conditions are advantages of this new media. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
998.
A series of 2-, 3-, and 4-substituted (fluorobenzoylimino)-3-aryl-4-methyl-1,3-thiazolines (2a–j) were synthesized in good yields by the base-catalyzed cyclization of corresponding 1-(fluorobenzoyl)-3-(fluorophenyl)thioureas (1a–j) with α-bromoacetone in water. Compared to the reactions in conventional nonaqueous solvents under inert anhydrous conditions, the aqueous medium provides a much cleaner, more efficient, and simpler method for synthesis. 相似文献
999.
An efficient synthesis of some novel 2-aroylimino-3-aryl-4-phenyl-1,3-thiazolines was carried out by base-catalyzed cyclization of 1-aroyl-3-arylthioureas with acetophenone in the presence of bromine. The structures were confirmed by spectroscopic data, elemental analyses, and in one case (2t) by single-crystal X-ray diffraction data. 相似文献
1000.
M. Saeed Abaee Mohammad M. Mojtahedi M. Mehdi Zahedi S. Mohammad Bolourtchian 《合成通讯》2013,43(2):199-206
A remarkably efficient double‐crossed aldol condensation of tetrahydropyran‐4‐one with a variety of aromatic aldehydes is described at room temperature in the presence of (trimethylsilyl)diethylamine and lithium perchlorate under solvent‐free conditions. Excellent yields of 3,5‐bis(arylmethylidene)pyranones are achieved in a facile one‐pot general procedure. 相似文献