共查询到20条相似文献,搜索用时 15 毫秒
1.
Michel Farnier Michle Brost Bernard Hanquet Roger Guilard 《Journal of heterocyclic chemistry》1986,23(2):513-516
Thermal decomposition of azido-1,2-dithienylethenes 1 gave thienyl 4H-thieno[3,2-b]pyrroles 3 . For the 3,4-disubstituted thiophene derivatives 2 , the same reaction led to the amino-1,2-dithienylethenes 4 . In contrast, only azido-1,2-dithienylethanes 7 led to thienyl-5,6-dihydro-4H-thieno[3,4-b]pyrroles 8 . The structure of the obtained derivatives was established on the basis of 1H nmr, ir, and mass spectral data. 相似文献
2.
E. Montaudon M. Campagnole F. Flies B. Maillard 《Journal of heterocyclic chemistry》1991,28(2):459-463
The induced decomposition of t-butyl hex-5-enyl peroxide in good hydrogen donor solvents led to 2-substitude tetrahydropyrans and adduct peroxides. The presence of substituents on the hexenyl moinety influenced seriously the relative ratio of the heterocycle and the adduct peroxide. 相似文献
3.
Roger Spitz Jean-Loup Lacombe Michel Primet 《Journal of polymer science. Part A, Polymer chemistry》1984,22(10):2611-2624
In this article we describe a study of the reaction between triethylaluminium (TEA) and ethylbenzoate (BE) in a heptane solution by Fourier transform, infrared (IR), and ultraviolet (UV) spectroscopy. These compounds were chosen as a model of the cocatalytic solution used with a Ziegler-Natta catalyst supported on MgCl2 for the stereospecific polymerization of propene. In the polymerization concentration range a 2 TEA:1 BE yellow complex was added to the solution and no free BE could be detected at a AI/BE molar ratio above 2: the solution contained only free and complexed TEA. The complex decomposed spontaneously to a colorless aluminium alcoholate. The rate of decomposition remained slow at room temperature and the reaction was enhanced by heating or by a high AI/BE ratio or high AI concentration. The decomposition was inhibited in the presence of an olefin. 相似文献
4.
Comparison of the ‘normal’ and mass analysed ion kinetic energy spectra of 1-phenyl-1,2,3-triazole and a few D and 13C labelled derivatives indicates that the ions may follow two competing decomposition pathways: a simple rupture without rearrangement is preferred by the ions of high internal energy content (normal spectrum). On the other hand, for low internal energy metastable ions, loss of HCN is more important and occurs after a complete randomization of the H atoms. 相似文献
5.
Ewa Drożdż-Cieśla A. Małecki Barbara Jajko 《Journal of Thermal Analysis and Calorimetry》2008,92(3):939-944
Thermal decomposition of zirconyl oxalate hydrate was studied using DTA, TG, QMS and XRD techniques. It was shown that decomposition
occurs in two stages: dehydration to anhydrous oxalate and next, decomposition to zircon oxide (zirconia). These steps are
not well separated. We observed that significant amount of water are released during second stage of decomposition. Zircon
dioxide is obtained in tetragonal form. Moreover, we consider some dependences between conditions of preparations zirconyl
oxalate hydrate and some properties of solid product of its decomposition.
Although the reaction of thermal decomposition of zirconyl salts is generally utilized in technology, many aspects of this
process are still not sufficiently explained. In our work, we present some new interesting observations concerning thermal
behaviour of zirconyl oxalate. 相似文献
6.
Gaston Vernin Chhan Siv Svend Treppendahl Jacques Metzger 《Helvetica chimica acta》1976,59(5):1705-1724
The aprotic decomposition of 5-amino-3, 4-dimethyl-isoxazole with excess isoamyl nitrite in aromatic solvents (alkylbenzenes, polyalkylbenzenes, anisole etc.) and in heteroaromatic solvents (thiophene, 2, 4-dimethylthiazole, pyridine, 4-alkylpyridines, dimethyl- and trimethyl-pyridines) leads to 5-aryl- and 5-heteroaryl-isoxazoles in yields of about 40%. This method provides a new way of obtaining 5-iodo-3, 4-dimethyl-isoxazole by the aprotic decomposition of the corresponding amine in the presence of iodine (yield: 30%). The relative reactivity of the 3,4-dimethylisoxazol-5-yl radical in alkyl benzenes, in anisole and in alkylpyridines is very similar to that of other heteroaromatic radicals with the radical site next to a sulfur or an oxygen atom. The radical shows electrophilic character because of the inductive effect of the oxygen atom. In the pyridine series an abnormally high percentage of 2-substitution occurs. This may be explained by a solvatation effect. The characteristic GLC., NMR. and MS. data are reported for most of the compounds studied. 相似文献
7.
Jean-Bernard Weber Jacques Porret Andr Jacot-Guillarmod 《Helvetica chimica acta》1978,61(8):2949-2955
Studies of Organometallic Compounds. XVII Synthesis of Tetracyclohexyltitanium Tetracyclohexyltitanium is prepared by reaction of TiCl4 or Ti(OC4H9)4 with dicyclohexylmagnesium in pentane or ether at - 30°. Some aspects of its reactivity and its decomposition are described. 相似文献
8.
M. Gruselle 《Tetrahedron》1975,31(18):2283-2287
Undecyl chloride formed by decomposition of perdodecanoic acid in hexachloroacetone showed CIDNP signals. Thermal decomposition of aliphatic peracids was studied by this way. The first step is the formation of a singlet radical pair of undecyl and hydroxyl radicals which do not recombine into ROH and give exclusively transfer on the solvent. 相似文献
9.
P. Miranda
Jr M. F. Máduar J. Zukerman-Schpector J. R. Matos 《Journal of Thermal Analysis and Calorimetry》2007,87(3):793-795
Lanthanide picrates with 1,3-dithiane-1,3-dioxide ligand were synthesized
and characterized. Thermal decomposition of these compounds by TG/DTG and
DSC and structural studies were performed. It was found that the compounds
are comprised in a single isomorphous series and their thermal decomposition
occurs as exothermic events. The final products were found to be lanthanide
dioxysulfates. 相似文献
10.
Thermal decomposition of copper hydrogen orthoarsenate monohydrate has been studied by isothermal technique and X-ray diffraction method. The decomposition to the final diarsenate proceeds through the formation of an intermediate anhydrous salt. The lattice parameters for the starting monohydrate and the two dehydrated-decomposed compounds have been evaluated. 相似文献
11.
12.
Synthesis and reactivity of 3-aryl-1-(3,4-dimethyl-5-isoxazolyl)-triazenes and 4-arylazo-3,4-dimethylisoxazol-5-ones According to the experimental conditions and the nature of the substituents on the aromatic ring, aryldiazonium salts react with 5-amino-3,4-dimethylisoxazole ( 3 ) leading to either 3-aryl-1 (3,4-dimethyl-5-isoxazolyl)-triazenes ( 1A ) or 4-arylazo-3,4-dimethylisoxazol-5-ones ( 4 ). Analyses of the products resulting from thermal decomposition of these triazenes in aromatic substrates and in DMSO and their behaviour in acidic medium show that it is essentially the arylazo form 1B which is reactive. 相似文献
13.
J. M. Augl 《Journal of polymer science. Part A, Polymer chemistry》1970,8(11):3145-3153
Phenylated, ordered imide–quinoxaline copolymers of high oxidative-thermal stability were prepared by one-step solution condensation of aromatic tetraamines with N,N′-bis(4-benzilyl)pyromellitimide. Polymerization in m-cresol leads to high molecular weight polymers that remain soluble. Thermal gravimetric analysis and isothermal decomposition at 400°C shows that these polymers are as stable as polyimides or polyquinoxalines. The polymer decomposition temperatures range between 495 and 550°C, depending upon structure. Also, the rate of isothermal decomposition at 400°C in air showed a strong dependency of weight loss on structure. Tough films were cast from solution. 相似文献
14.
Bunchiro Yamada Hiroaki Kamei Takayuki Otsu 《Journal of polymer science. Part A, Polymer chemistry》1980,18(6):1917-1922
Thermal decomposition of α,α′-azobisisobutyronitrile (AIBN) and dimethyl α,α′-azobisisobutyrate (MAIB) in the presence of a large amount of tin tetrachloride was investigated to determine the effect of complex formation on the decomposition rates and yields of the recombination products. The addition of tin tetrachloride significantly increased the decomposition rates; the observed first-order rate constant increased by factors of 4.5 and 17 at molar ratios of [SnCl4]/[AIBN] = 21.65 and [SnCl4]/[MAIB] = 19.53, respectively. It was found that the decomposition of these azo compounds was also accelerated by the addition of a comparable amount of donor solvent such as ethyl acetate or propionitrile to tin tetrachloride and that the enhancement in rate was accounted for by a larger frequency factor in the Arrhenius equation. Furthermore, the addition of tin tetrachloride seemed to suppress the formation of recombination products, tetramethyl succinonitrile and dimethyl tetramethylsuccinate, of the radicals produced by decomposition. 相似文献
15.
The preparation, stability and storage of pure samples of hexamethyldilead is discussed. Thermal decomposition in hydrocarbon and carbon tetrachloride 相似文献
16.
Addition-elimination reactions from germanium heterocycles I. Germadioxolanes (X?Y?O) The reactivity of 2-germa-1,3-dioxolanes is studied with unsaturated compounds such as carbonyl compounds (aldehydes and ketones) or heterocumulenes (PhNCO, PhNCS). The formation of mono- and di-insertion derivatives is observed. The structure of these adducts is established and their decomposition process, at atmospheric pressure or at high pressure, is precised. The mechanism of these addition-elimination reactions is established from 4,5-disubstitued germadioxolanes. The reaction takes place under steric control. The consecutive elimination reaction proceeds by a mechanism of intramolecular nucleophilic substitution. 相似文献
17.
Manganese dioxide oxidation of the hydrazone derivative of tert-butyldimethylsilyl acetophenone gave 2-tert-butyldimethylsilyl-1-phenyldiazoethane (17) an isolable diazocompound. Thermal and Rh(II)-catalyzed decomposition of diazosilane 17 in cyclohexane led to 1-tert-butyldimethylsilyl-1-phenylethylene (19) as the major product. The formation of alkene 19 presumably involves (tert-butyldimethylsilyl)methylphenylcarbene (21), which undergoes preferential 1,2-silyl migration as opposed to 1,2-hydrogen migration. Thermal decomposition of 17 in cyclohexane under oxygen gave substantial amounts of tert-butyldimethylsilyl acetophenone, presumably by reaction of the intermediate carbene with oxygen. Thermal decomposition of 17 in methanol led to alkene 19 and 2-tert-butyldimethylsilyl-1-methoxy-1-phenylethane (22) as major products, along with a significant amount of trans-1-tert-butyldimethylsilyl-2-phenylethylene (20). Kinetic studies indicate that these products are not derived from acid-catalyzed decomposition of the diazocompound 17. Formation of the methyl ether product 22 suggests the involvement of a beta-silyl carbocation intermediate, and solvent isotope effect studies indicate that this cation is at least partially derived from protonation of diazocompound 17 by neutral methanol. Photochemical decomposition of 17 in methanol produced the alkene 19 (97%) along with a small amount (2.4%) of the methyl ether 22. Capture of a photochemically generated carbene 21 by methanol is the proposed origin of this minor product. Geometry optimization of trimethylsilylmethylphenylcarbene (8) and carbene 21 at the HF/6-31G computational level led to a conformation consistent with a hyperconjugative interaction between the vacant p-orbital of these carbenes and the adjacent C-Si bond. Carbenes 8 and 21 are not energy minima at the B3LYP/6-31G level, where they rearrange to alkenes without barrier via silyl migration. These theoretical findings contrast with the proposed trapping of carbene 21 by methanol and oxygen. 相似文献
18.
Lon J. Mathias Peter D. Livant Sharf U. Ahmed 《Journal of polymer science. Part A, Polymer chemistry》1987,25(10):2711-2716
Several new copolymers have been synthesized. Initial polycondensation of mixtures of aryl and arylalkyl carboxylic acids containing aromatic hydroxyl and amine substituents led to random copolyamides. Thermal cyclization of these prepolymers (inherent viscosities of about 0.2 dL/g) gave copolybenzoxazoles with inherent viscosities of about 1.4 dL/g. Thermal stability as measured by TGA was similar for the 1:1 copolymers and the homopolymers containing hydrocinnamic units; i.e., catastrophic decomposition occurred at 450°C. Copolymers with lower ratios of the hydrocinnamic units displayed greatly improved thermal stability while maintaining good molecular weight. 相似文献
19.
E. Styczeń W. K. Jóźwiak M. Gazda D. Wyrzykowski Z. Warnke 《Journal of Thermal Analysis and Calorimetry》2008,91(3):979-984
Thermal decomposition of compounds consisting of tetrahalogenocuprate(II), [CuBrnCl4−n]2− (n=0–4) anions and a tetraethylammonium cation has been studied using TG-FTIR, TG-MS, DTA and DTG techniques. The measurements
were carried out in an argon and air atmospheres over the temperature range 293-1073 K. The products of the thermal decomposition
were identified by IR and Far Infrared (FIR) spectroscopy as well as X-ray powder diffractometry. 相似文献
20.
Studies of Organometallic Compounds. XVII: Synthesis and Caracterisation of μ-oxo-bis(dicyclopentadienylmethyltitane IV) (Cp2TiCH3)2O is obtained by reacting (Cp2TiCl)2O with methyllithium. IR., NMR. and MS. spectrum are reported. Autocatalytic decomposition of the product is inferred from differential thermal analytic measurements. 相似文献