戊烯

Quinone methides, generated in situ from the reaction of 4-hydroxycoumarin with benzaldehyde, formaldehyde and pentanal, underwent the Diels-Alder reaction with silyl enol ethers to give a series of 3,4-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran derivatives in high yields.

通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应，以较高产率合成了一系列含有硅氧基的3，4-二氢-2H，5H-吡喃并[3，2-c][1]苯并吡喃-5-酮衍生物。

Accordingly, in the original reaction (formation of B from cyclopentadiene and benzoquinone) Diels and Alder found only one of the following six conceivable stereoisomers of B.

因此，在该原始反应中(即通过P-苯醌和过量的环戊二烯生成B)，Diels and Alder发现在他们推测的六个立体异构中，只有一个出现。

Furthermore, the main volatiles rom Hippophae rhamnoides included Nonane, Octane, 3-methyl-1-Butanol, Pentanal, 2-methyl- Butanal, 2-Hexen-1-ol, 2-Hexenyl benzoate in close natural state.

在近自然状态下，壬烷、辛烷、3-甲基丁醇、戊醛、2-甲基丁醛、2-壬烯醇、2-苯甲酸叶醇酯为沙棘枝叶主要挥发物组分。

Mission:"equality and mutual benefit, reputation first, unity and cooperation and friendship between the long-term" supply products: ethylenediamine; diethylamide; triethylamine; Diethylenetriamine; three ethylene diamine; three ethylene amines 40; 40 Five ethylene amines; five ethylene amines 6; caprolactam; DMF; allyl amine; N, N dimethylaniline; propylamine; are butylamine; are TOA; 3 Poly Cyanamide; 1,2 c diamine; ethanolamine; diethanolamine, triethanolamine; potassium iodide, potassium hydroxide, potassium permanganate, toluene, xylene, toluene of chlorine ; Acetone, butanone; acetylacetone; ethyl acetate, butyl acetate; Y-butyrolactone; DMC; acetyl of methyl acetate; Sanfu acetyl acid; Sanfu acetyl B Ethyl; methanol, ethanol, isopropanol; propylene glycol; glycerol; propargyl alcohol; 1.3 propylene glycol; xylitol; acetic acid; have acid; mercaptoacetic acid; vary Bitterness; adipic acid; trifluoroacetic acid; oxalic acid, the amino acid; o-amygdalin acid; DL-Acid; anhydrous piperazine; six non-piperazine, furfural, castor oil, ethylene Aldehyde; glutaraldehyde, multi-POM; isopropyl ether; anisole; tetrahydropyrrole; pure pyridine; 1.2 dichloroethane; methylene chloride, chloroform, carbon tetrachloride; hydrazine hydrate; Nonylphenol;-m-cresol; Se phenol; phenol; the tert-butyl phenol; Titanium Dioxide; iron; full Tangfen; Bisphenol A; azo two different nitrile; sodium azide; sodium carbonate ; Sodium chloride; iron oxide; cuprous chloride; thionyl chloride; D4; sodium bicarbonate; ammonia, potassium chloride; anhydrous sodium sulphite; ammonium persulfate; glycol Dingmi; B Glycol ether; calcium chloride; cyclohexanone; cyclohexane, methyl tertiary butyl ether, potassium carbonate, ferric chloride, potassium nitrate; Linsuansanna; zinc oxide; sodium nitrite; antimony oxide; Tartrate; OP-10; TX-10; tablets base; AES; sodium benzoate, sodium citrate; partial sodium silicate, sodium perborate, a sodium carbonate, sodium benzene; Asia sodium chlorate; Wuluo Care products; urea; hydrochloric acid, sulfuric acid, lactic acid; amino acid, hydrogen peroxide, ammonium bicarbonate

公司宗旨：&平等互利，信誉至上，团结合作，友谊长久&乙二胺；二乙胺；三乙胺；二乙烯三胺；三乙烯二胺；三乙烯四胺；四乙烯五胺；五乙烯六胺；己内酰胺；二甲基甲酰胺；烯丙基胺；N，N二甲基苯胺；正丙胺；正丁胺；正辛胺；三聚氰胺；1，2丙二胺；一乙醇胺；二乙醇胺；三乙醇胺；碘化钾；氢氧化钾；高锰酸钾；甲苯；二甲苯；对氯甲苯；丙酮；丁酮；乙酰丙酮；醋酸乙酯；醋酸丁酯；Y-丁内酯；碳酸二甲酯；乙酰乙酸甲酯；三伏乙酰乙酸；三伏乙酰乙酸乙酯；甲醇；无水乙醇；异丙醇；丙二醇；丙三醇；丙炔醇；1.3丙二醇；木糖醇；冰醋酸；己醛酸；巯基乙酸；异辛酸；己二酸；三氟乙酸；乙二酸；对氨基苯乙酸；邻氯苦杏仁酸；DL-扁桃酸；无水哌嗪；六无哌嗪；糠醛；蓖麻油；乙二醛；戊二醛；多聚甲醛；异丙醚；苯甲醚；四氢吡咯；纯吡啶；1.2二氯乙烷；二氯甲烷；三氯甲烷；四氯化碳；水合肼；壬基酚；纯间甲酚；硒酚；苯酚；对叔丁基苯酚；钛白粉；铁粉；全糖粉；双酚A；偶氮二异丁腈；叠氮化钠；碳酸钠；氯化钠；三氧化二铁；氯化亚铜；氯化亚砜；D4；碳酸氢钠；氨水；氯化钾；无水亚硫酸钠；过硫酸铵；乙二醇丁醚；乙二醇乙醚；氯化钙；环己酮；环己烷；甲基叔丁基醚；碳酸钾；三氯化铁；硝酸钾；磷酸三钠；氧化锌；亚硝酸钠；氧化锑；酒石酸；OP-10；TX-10；粒碱；AES；苯甲酸钠；柠檬酸钠；偏硅酸钠；过硼酸钠；过碳酸钠；苯磺酸钠；亚氯酸钠；乌洛托品；尿素；盐酸；硫酸；乳酸；氨基磺酸；双氧水；碳酸氢铵

First of all, acrylamide, pentaerythrite and ammonium ceric nitrate were mixed by some concentration in an aqueous solution.

首先将丙烯酰胺、季戊四醇和硝酸铈铵分别配制成一定浓度的水溶液。

The biomarkers such as the n-Alkanes, the isoprenoids, the terpane, and cholestane were detected through GC-MS analysis. Based on the study of the biomarkers, the biological evolution during Permian and Triassic can be divided as three stages, namely, the mixing source stage of low biota such as thallose and advanced plant in late Permian (below bed 63), the stage of low biota such as thallose in the boundary transitional layer (bed 63-69) and the mixing source stage of advanced plant and low biota such as thallose in early Triassic (above bed 69). What's more, the second stage near the boundary transitional layer can be subdivided into 4 stages. The stages of biota evolution is close related with sedimentary environment changing and the boundary transitional layer.

利用GC—MS分析技术，在陆相地层中检测出正构烷烃、类异戊二烯烷烃、萜烷和甾烷类生物标志化合物并根据生物标志化合物和特征值研究，将二叠系—三叠系生物演化划分为三个大的阶段，即晚二叠世的菌藻类低等生物与高等植物混源阶段（63层以下），界线异常层的菌藻类低等生物阶段（63-69层）和早三叠世高等植物与菌藻类低等生物混源阶段（69层以上），界线附近异常层的第二阶段又进一步细分为4个次一级阶段，生物演化阶段与沉积环境变化及界线异常层具有非常密切关系。

The emphasis was on chemical properties,application,main production methods,market,and prospects of main deriva- tives of acetaldehyde such as ethyl acetate,pentaerythritol,glyoxal,peracetic acid, crotonaldehyde and pyridine.

介绍了国内外乙醛及其主要衍生物的生产技术发展及其市场供需状况，尤其对乙醛主要衍生物乙酸乙酯、季戊四醇、乙二醛、乙醛酸、丁烯醛、吡啶的化学性质与用途、主要生产方法、市场供需状况及开发前景作详细介绍和分析。

In there compounds, the cyclopentadiene ring has only four hydrogens.

在这些化合物里，环戊二烯环只有4个氢。

I cyclopentadiene companies from the methylation of MMT to the synthesis, entirely by domestic procurement of raw materials, in the "quantity" can be fully guaranteed for production.

我公司从环戊二烯的甲基化到MMT的合成，原料完全由国内采购，在&量&上可完全保证生产所需。

The process of preparation for 2-chloro-5-chlormethylpyridine by cyclopentadiene cyclization needs to do more research by using green process and decreasing the wastes.

2-氯-5-氯甲基吡啶的合成采用环戊二烯环合法，需研发有利于环境的绿色生产工艺，减少三废，治理三废。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。