|
|
|
|
|  | | 为了更好的帮助您理解掌握查询词或其译词在地道英语中的实际用法,我们为您准备了出自英文原文的大量英语例句,供您参考。 | |
Both 2,5-trans and 2,5-cis disubstituted 2-tert-butyl-5-(indol-3-yl)methylimidazolidin-4-ones were synthesised and their enolates were prepared using LDA.
|
| 例句来源 | |
A convenient method for the synthesis of symmetric and asymmetric diamides of amino acids including DOPA and citric acid from 2-tert-butyl-1,3-di(N-hydroxysuccinimidyl)citrate and 1-tert-butyl-2,3-di(N-hydroxysuccinimidyl)citrate is described.
|
| 例句来源 | |
The experiment was carried out with the stereoisomeric r-2-tert-butyl-4-methyl-trans-7-methyl[2]1,3-dioxepane.
|
| 例句来源 | |
The standard (p° = 0.1 MPa) molar enthalpies of formation Δf Hmo(1) at the temperature T = 298.15 K were measured using combustion calorimetry for 2,5-dimethylfuran, 2-tert-butylfuran, and 2,5-di-tert-butylfuran.
|
| 例句来源 | |
Treatment of 2-(tert-butyl-NNO-azoxy)anilines with phosgene at 20 °C was proposed as a novel route to 1,2,4-benzotriazin-3(4H )-one 1-oxides.
|
| 例句来源 | | 更多 |
|
|
|

| | The effect of aqueous ethanol (50% v/v) on the activity of purified mushroom polyphenol oxidase has been found to be as follows: (1)The oxidation of catechol or pyrogallol is greatly stimulated,an increase in the rate of oxygen uptake of over 100% having been invariably observed with catechol as the substrate,whereas the oxidation of other substituted o-dihydric phenols is inhibited in 50% ethanol. (2)When excess ascorbic acid is added to the reaction mixture to reduce o-quinone back to catechol as soon as ... | | (一)乙醇能够使多酚氧化酶接触儿茶酚及焦性没食子酸氧化的活力提高,在50%乙醇溶液中,以儿茶酚为底料时,多酚氧化酶的活力比没有乙醇存在时的活力高出一倍以上。(二)50%的乙醇不能使多酚氧化酶接触其他双酚衍生物氧化的活力提高,相反地却有抑制作用。(三)无论有无抗坏血酸的存在,50%乙醇对多酚氧化酶活力的提高程度是一样的,在有一定量的抗坏血酸的存在下,多酚氧化酶对儿茶酚的 Michaelis 常数(25℃)在水溶液及50%乙醇溶液中各为0.072×10~(-3)M 及0.49×10~(-3)M。(四)乙醇的存在,并不影响多酚氧化酶氧化儿茶酚作用时氧气被完全还原为水的作用。无论乙醇存在与否,每一分子底料的氧化,都消耗一个氧原子。(五)其他水溶性有机溶剂对多酚氧化酶氧化儿茶酚活力的影响不同,如甲醇、异丙醇、叔丁醇、丙酮等能使酶活力提高;但1,4-二氧己圜、乙二醇、甘油等则有抑制作用。50%丙酮能使酶活力提高约3倍。 | | 文摘来源 | | The addition reactionof thiophenol and tert.-butylacetylene took Place slowly in the dark,giving a 1:1 adduct and smaller amounts of a 2:l adduct. The reaction could be accelerated by ight and benzoyl peroxide yielding the same Products.The reaction of thiophenol and tert.-butylacetylene in the presence of sodium ethoxide took Place very slowly,only a small amount of a 2:1 adduct was obtained. The 1:1 adduct interacted with mercuric chloride in aqueous solution yielding a carbonyl compound which... | | 苯硫酚与叔丁基乙炔在黑暗中的加成反应进行緩慢,得到的是1:1加成物和少量的2:1加成物。这个反应受光及苯甲酰过氧化物的作用而加速,生成同样的产物。苯硫酚与叔丁基乙炔在乙醇鈉存在下的反应进行很緩慢,只得到少量的2:1加成物。 1:1加成物藉氯化汞在水溶液中分解所得到的羰基化合物与2,4-二硝基苯肼作用生成腙。这个腙与硫代乙酸和叔丁基乙烛的加成物与2,4-二硝基苯肼作用时所得到的腙相同,表明分解产物中的羰基化合物为叔丁基乙醛。1:1加成物因此是∝-叔丁基-β-苯硫基乙烯。根据这些結果,作者建議这个加成反应为游离基历程。 | | 文摘来源 | | The telomerization of methyl acetate with ethylene, using di-tert.-butyl peroxide, benzoyl peroxide, or azo-bis-iso-butyronitrile as initiator, has been studied. Experimental results show that di-tert.-butyl peroxide is much more efficient than benzoyl peroxide and azo-bis-iso-butyronitrile. | | 利用过氧化叔丁基、过氧化苯甲酰或偶氮异丁腈为引发剂,进行乙烯与乙酸甲酯的调节聚合反应,实验结果说明其中以过氧化叔丁基效率最佳,余二者均较差。过氧化叔丁基以1.5%用量,调聚物的平均收率可达加入酯的14%。三种引发剂的用量在0.12%至4.6%的范围内改变,调聚物收率的增加与引发剂用量的增加几成直线关系。由过氧化叔丁基引发的调聚产物中,分离并鉴定月桂酸、软脂酸、硬脂酸及二十酸等四种高极脂肪酸。除调聚酯外,尚含相当量不水解的中性物。由偶氮异丁腈引发的反应液中,分离出引发剂自由基的二聚体1,1,2,2-四甲基丁二腈,其量几占加入引发剂量55%。 | | 文摘来源 | |   | | << 更多相关文摘 |
|
相关查询: | |
对查询结果不满意
|
|
|
|