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1.
研究了二叔丁基羟胺(DTBHA),二叔丁基氮氧自由基(DTBNO),2,2,6,6-四甲基-4-羟基哌啶羟胺(TMHPHA)和2,2,6,6-四甲基-4-羟基哌啶-1-氧自由基(TMHPO)对过氧化苯甲酰(BPO)60℃引发的苯乙烯(M1)-丙烯腈(M2)共聚合的阻聚物行为。结果表明,这些阻聚剂对St-AN共聚均表现良好的阻聚行为,其中氮氧自由基优于相应羟胺。同时观察到St-AN竞聚率的改变,羟胺  相似文献   

2.
茵陈挥发油的超临界CO2萃取法与水蒸气蒸馏法提取的比较   总被引:10,自引:0,他引:10  
采用超临界CO2萃取法与水蒸气蒸馏法从菌陈中提取挥发油,用GC-MS法测定其化学成分和相对含量,对两种提取方法所得的挥发油进行比较,水蒸气蒸馏法提取菌陈挥发油的产率为0.03%(w),主要成分为匙叶桉油烯醇、吉玛烯D、反式-石竹烯、2,4-戊二炔苯、β-金石欢烯等;超临界CO2萃取法提取的产率为0.15%(w),主要成分为百里酚、β-红没药烯、2-异丙基-4-甲基-1-甲氧基苯、异百里酚、2-特丁基-4-(2,4,4-三甲基戊基)苯酚、β-杜松烯等。  相似文献   

3.
啤酒花酊挥发性香味成分的GC-MS分析   总被引:4,自引:0,他引:4  
利用连续液-液提取技术分离啤酒花酊的香味成分,用GC-MS和双柱复检法对啤酒花酊的挥发性化学成分进行了定性分析,质谱共鉴定出44种化合物,其主成分为4,4-dimithy1-3,5-dioxahexaldoxin-2,6-dione和3-甲基丁酸。对主要成分进行定量和重现性比较,结果令人满意。该法简便、快速,为食品工业添加剂的质量监控和常规分析提供参考。  相似文献   

4.
紫玉兰叶油化学成分的气相色谱/质谱法分析   总被引:10,自引:0,他引:10  
李峰  田来进  邵晶  朱果逸 《分析化学》2000,28(7):829-832
采用常规水蒸汽蒸馏法提取出紫玉兰叶油,经气相色谱-质谱联机分析,分离出40多个峰,鉴定出32种化合物,主要是大根香叶烯、檀紫三烯,石竹烯3,7二甲基-1,3,7-辛三烯、莰烯等,占总峰面积的95%。  相似文献   

5.
超临界CO2萃取石菖蒲有效成分的GC-MS分析   总被引:7,自引:1,他引:7  
采用超临界CO2流体萃取技术从石菖中萃取分离挥发油,用气相色谱-质谱联用技术测定其化学成分,从中鉴定出26种成分,并测定了其相对含量,主要成分为:顺-细辛脑、反-细辛脑、绿叶烯、石竹烯、蛇麻烯、甲基丁子香酚、榄香纱,顺-罗勒烯等。  相似文献   

6.
刘百战 《分析化学》2000,28(12):1489-1492
采用固相微萃取和同时蒸馏萃取技术分离芥末膏制品的挥发性成分,用GC/MS分析鉴定,对总离子流色谱的峰面积进行归一化定量。共鉴定了22种化学成分,占总峰面积的99%以上,其中含硫化合物8种,含氮化物3种,含氧化合物11种。最主要的成分是异硫氰酸烯丙酯,其次是丙二醇,其他主要成分还有对羟基二叔丁基甲苯、油酸、9-十六烯酸、棕榈酸、5-甲基甲氢噻吩-2酮、二烯丙基二硫化物,异硫氰酸苯乙酯等。比较了各种萃取技术对分析结果的影响,同时蒸馏萃取法不能分离出水溶性成分如丙二醇等,在固相微萃取方法中,聚二甲基硅氧烷纤维头对极性较强的成分的取样效果不理想,聚乙二醇-二乙烯苯纤维头顶空取样的萃取效果最好。  相似文献   

7.
γ-甲基-δ-酮己酸,γ-异丙基-δ-酮己酸在碘化N-甲基-2-氯吡啶盐存在下分别同(R)-四氢噻唑-2-硫酮-4-羧酸乙酯反应,得到光学活性的(R)-N-(γ-甲基-δ-酮己酰基)四氢噻唑-2-硫酮-4-羧酸乙酯(1a)及光学活性的(R)-N-(γ-异丙基-δ-酮己酰基)四氢噻唑-2-硫酮-4-羧酸乙酯(1b)。1a,1b分别同(R,S)-α-苯乙胺反应得到光学活性的酰胺2a,2b,同时使(R,S)-α-苯乙胺拆分,得到光学活性的α-苯乙胺。  相似文献   

8.
二(2,6-二叔丁基-4-甲基苯氧基)钐配合物催化甲基丙烯酸甲酯聚合扈晶余,齐贵中(中国科学院长春应用化学研究所稀土化学与物理开放实验室长春130022)沈琪(苏州大学化学系苏州)关键词钐配合物,甲基丙烯酸甲酯,聚合二价稀土有机化合物具有很强的还原性...  相似文献   

9.
3,5—二甲氧基苯乙醛和丙二酸单乙酯的Knoevenagel缩合   总被引:1,自引:0,他引:1  
从3,5-二甲基苯乙醛和丙二酸单乙酯的Knoevenagel缩合反应得到2个产物,其一经证实是重排生成的4-(3,5-二甲氧苯基)-3-丁烯酸乙酯,另一个是2',4',2″,4″-四甲氧基-2,3:6,7-二苯并-9-氧杂双环[3.3.1]壬-2,6-二烯。经元素分析、IR、NMR、MS、和X射线衍射证实前者不发生可逆重排为其2-烯酸酯异构体的反应。  相似文献   

10.
合成了新型的四(3,5-二叔丁基-4-个甲氧基苯基)卟啉和相应的金属(M=Ni、Cu、Co、Zn)卟啉,用 ̄1HNMR、 ̄(13)CNMR、DEPT谱鉴定了它们的结构,并用 ̄1H、 ̄(13)C谱讨论了这些卟啉化合物的中心金属离子对环流的影响。  相似文献   

11.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

12.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

13.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

14.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

15.
Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.  相似文献   

16.
17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

19.
Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.  相似文献   

20.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

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