Perfluoro-4-methyl-1,3-dioxole: a new monomer for high-Tg amorphous fluoropolymers

A 4-Chloro-5-trifluoromethyl-2,2,4-trifluoro-1,3-dioxolane (1) was synthesised by reaction of CF₂(OF)₂ with CF₃CHCFCl; the elimination of HCl from (1) in basic conditions led to the formation of dioxole perfluoro-4-methyl-1,3-dioxole (2). Both these synthetic steps gave the corresponding product in high yield.A new synthetic route for the preparation of CF₃CHCFCl, starting from CF₂ClBr and CH₂CF₂, together with some examples of polymerisation products obtained by reaction of dioxole (2) with fluoroolefins are also reported.     

Synthesis of β-branched Morita-Baylis-Hillman-type adducts from 1,3-diaryl-2-propynyl trimethylsilyl ethers and aldehydes catalyzed by potassium tert-butoxide

1,3-Diaryl-2-propynyl trimethylsilyl ethers were easy to isomerize into the corresponding siloxyallenes using a catalytic amount of potassium tert-butoxide under very mild conditions. The siloxyallenes reacted in situ with various aldehydes to afford Z-selective β-branched Morita-Baylis-Hillman-type adducts in a one-pot reaction after acid treatment.     

Preparation and steric structure of 3(2H)-pyridazinones and 1,2-oxazin-6-ones fused with three- to six-membered saturated carbocycles or norbornane skeleton

Summary Reactions ofcis-2-(4-methylbenzoyl)-cyclopropane- (1) and-cyclobutanecarboxylic acids (2), the stereoisomeric cyclohexyl homologues (3 and4), and di-endo-3-(4-methylbenzoyl)-bi-cyclo-[2.2.1]heptane-2-carboxylic acid (5) with hydrazines yield the cycloalkane-condensed (3(2H)-pyridazinones6–9 and the norbornane di-endo-fused derivatives10. With hydroxylamine, compounds1 and3–5 were transformed to the cycloalkane- and norbornane-condensed 1,2-oxazin-6-ones11–14. Transformation of3–5 led to thetrans-hexahydroanthrone17a and its methylene-bridged analogue24. From the stereoisomeric hexahydro-1(3H)-isobenzofuranones20 and21, the partly saturated anthrones were also prepared; the products (16b and17b) contain the methyl substituent in position 6. On reduction,16b yield the 2-methyloctahydroanthracene22. The structures of the compounds were proved by¹H and¹³C NMR spectroscopy, making use of NOE, DEPT, and CH-COSY techniques.

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Synthese und räumliche Struktur von mit drei- bis sechsgliedrigen gesättigten Homocyclen oder Norbornan kondensierten 3(2H)-Pyridazinonen und 1,2-Oxazin-6-onen

Zusammenfassung Die Reaktion voncis-2-(4-methylbenzoyl)-cyclopropan-(1) und-cyclobutancarbonsäuren (2), der stereoisomeren cyclohexyl-Homologen (3 und4) und von di-endo-3-(4-methylbenzoyl)-bicyclo[2.2.1]heptan-2-carbonsäure (5) mit Hydrazinen ergibt die cycloalkankondensierten 3(2H)-Pyridazinone6–9 und das methylenüberbrückte di-endo-Derivat10. Die Verbindungen1 und3–5 wurden mit Hydroxylamin zu den cycloalkan- und norbornankondensierten 1,2-Oxazin-6-onen11–14 umgesetzt.3–6 reagierten zumtrans-Hexahydroanthron17a und seinem methylenüberbrückten Analogen24. Die teilweise gesättigten Anthrone wurden auch aus den stereoisomeren Hexahydro-1(3H)-isobenzofuranonen20 und21 hergestellt (16b und17b), wobei der Methylsubstituent jedoch in Position 6 lokalisiert ist. Reduktion von16b ergab das 2-Methyloctahydroanthracen22. Die Strukturen der Verbindungen wurden durch NMR-Spektroskopie abgesichert (¹H,¹³C, DEPT, CH-COSY, NOE).

     

FCC汽油在Ni-Mo-P/USY催化剂上的降烯烃工艺研究

制备了Ni-Mo-P/USY催化剂,采用透射电镜(TEM)及选区电子衍射(SAED)等手段对催化剂进行表征,证实了Ni、Mo活性组分可以较好聚合于USY载体中,并以抚顺石油二厂FCC汽油为原料,考察在该催化剂上进行的烯烃异构化及芳构化反应,探讨了工艺条件对催化性能的影响,结果表明,P改性后的Ni-Mo-P/USY催化剂比改性前性能大为提高,在反应温度320℃、反应压力2.0MPa、质量空速(WHSV)4.0h-1、氢油比(VH2/VOil)400∶1的条件下,汽油烯烃转化率、液体收率、产品异构化选择性和芳构化选择性分别可以达到62.1%、78.4%、47.2%和14.1%.     

Isomerization of n-Hexane over Chlorinated Pt/γ-Al2O3 Catalysts

Chlorided 0.57 wt. % Pt/γ-Al₂O₃ is a moderately active and highly selective catalyst for the isomerization of n-hexane at 300 °C when an excess of H₂ is present. Chlorine, which is continuously lost from the catalyst, may be replaced by adding a small amount of chloroform to the reactant stream. The catalyst exhibits activity and high isomerization selectivity even at 150 °C. Under the conditions of these lower temperature experiments, the equilibrium concentration of C₆ alkenes would be only 8 × 10^?7 Torr. This suggests that the classical mechanism, which involves the formation of n-hexene on the Pt, is not applicable. Rather, it is proposed that isomerization of the alkane occurs at acid sites on the catalyst, and the role of Pt is to catalyze the hydrogenation of any alkenes that might be formed as a result of cracking reactions. At temperatures ≤ 300 °C Brönsted acid sites are present in the catalyst, and presumably are responsible for the isomerization and cracking activity, but at higher temperatures Lewis acid sites play a dominant role.     

不饱和类硅烯H2C=SiNaF的DFT研究

用密度泛函理论方法, 在B3LYP/6-31+G(d, p)水平上研究了不饱和类硅烯H2C=SiNaF的结构. 结果表明, 不饱和类硅烯H2C=SiNaF共有四种平衡构型, 其中非平面的p-配合物型构型能量最低, 是不饱和类硅烯H2C=SiNaF存在的主要构型. 对平衡构型间异构化反应的过渡态进行了计算, 求得了转化势垒. 计算预言了最稳定构型的振动频率和红外强度.     

纳米介孔Ru-PPh2-SBA-16催化水相中高烯丙醇异构化反应的研究

以2-(二苯基膦)乙基三乙氧基硅烷和正硅酸乙酯为混合硅源, 采用延时共缩聚法经表面活性剂F127自组装合成了二苯基膦(PPh2)修饰的SBA-16纳米介孔分子筛(PPh2-SBA-16), 通过PPh2配体络合Ru(Ⅱ)化合物制备出固载化的Ru(Ⅱ)非均相催化剂(Ru-PPh2-SBA-16), 样品仍然保持了SBA-16的规整孔道结构. 以水相中高烯丙醇异构化反应为探针, 考察了所制备催化剂的催化性能, 发现其对目标产物具有高选择性, 虽然其催化活性略低于对应的均相Ru(Ⅱ)催化剂, 但该催化剂易与产物分离, 且重复使用三次后催化效率基本不变, 活性相与载体结合牢固, 不存在明显的脱落和流失, 因此更适合于工业化应用.     

Syntheses and optical properties of stable 8-alkylidene-bacteriochlorins mimicking the molecular structures of natural bacteriochlorophylls-b and g

We prepared bacteriochlorophyll(BChl)-b and g models by Diels-Alder reactions of 8-vinyl-chlorophylls with tetracyanoethylene. The resulting 8-alkylidene-bacteriochlorins with various substituent groups at the 3-position had the same π-conjugate as BChls-b/g. While the natural pigments isomerized by addition of an acid to afford the corresponding chlorins, the synthetic models were stable under the acidic conditions due to dialkylation at the 7-position. These BChl-b/g models are useful for investigating the optical properties of relatively unstable BChls-b/g.     

取代苯乙烯基吡嗪光物理行为的研究

合成了一系列带有不同推、拉电子能力的取代苯乙烯基吡嗪化合物，测定了它们在不同极性、不同粘度介质条件下的吸收光谱和发射光谱．结果表明，异构化和邻近效应是导致该类化合物荧光量子产率较低的主要原因，而取代基的性质对它们的发光行为以及光异构化行为均有很大影响     

AM1方法研究二硝基重氮酚异构化及热消除反应

ＡＭ１方法研究二硝基重氮酚异构化及热消除反应李永红，王，洪三国肖鹤鸣（江西师范大学化学系，南昌，３３００２７）（南京理工大学化学系）关键词二硝基重氮酚，异构化，热消除，过渡态二硝基重氮酚（ＤＤＮＰ）具有良好的性能，是重要的起爆炸药［１］．迄今为止，对...