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北京石油化工學(xué)院2026年研究生招生接收調(diào)劑公告

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shuoli

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The water–NaOH–agar gels of different compositions were studied and a ternary phase diagram wasprepared (Fig. 1). The following types of gels were obtained: (1) heterogeneous solution with solid phase containing agar (phase A), (2) heterogeneous solution with solid phase containing agar and alkali (phase B), (3) viscous liquid (phase C), (4) jelly-like highly vis-cous gel (phase D), (5) hard solid gel (phase E) or (6) heterogeneous solution with solid phase containing al-kali(phase F). Some compositions were non-gelling and merely gave either a simple solid–liquid mixtures with a large quantity of water (phase B) or solid–liquid
mixtures with a very low quantity of water (phase A). Phase F denotes the compositions in which the base itself was not soluble in the corresponding quantity of water. A gel having 80–50% water: 4–24% sodium hydroxide: 16–34% agar agar could give a hard solid gel useful as the GEBC. We selected a GEBC having 60% water, 10% NaOH and 30% agar agar for the re-actions. It was a translucent dark brown solid (10% NaOH-GEBC). The GEBC pieces were about 2 mm
thick and of irregular sizes of approximately 3–4 mm.The cyanoethylation of methanol with acrylonitrile was selected as a probe reaction to find out the opti-mum quantity of the GEBC required (Fig. 2). It was found that for 10 mmol of acrylonitrile 0.1 g of GEBC gave 100% yield of 3-methoxypropionitrile in 45 min.
The quantity of GEBC corresponds to the 2.5 mole.% of NaOH with respect to acrylonitrile. When the reaction was carried out using the GEBC pieces of dif-ferent dimensions, the yield of the reaction was found to be constant within the limit of experimental error.It is interesting to observe that the cyanoethylation
of 1-propanol is not reported by the classical procedure. For the cyanoethylation of 2-propanol a procedure is reported which uses solid KOH as a catalyst;[1] using this catalyst we obtained 80% of the prod-uct from 1-propanol. On the other hand, cyanoethylation of 1-propanol can be smoothly carried out using 10% NaOH-GEBC at 50◦C to obtain 96% of the product.
Cellosolve, with benzyl alcohol could also be cyanoethylated effectively by the NaOH-GEBC (Table 1 ).For classical reactions, different catalysts have been reported [2].
2-Methylpropan-2-ol and propan-2-ol could not be cyanoethylated and hence were used as solvents for the reaction. The cyanoethylation of other alcohols was then studied in the presence of 10% NaOH-GEBC. Also, except for methanol which caused slight whiten-ing of an otherwise dark brown coloured GEBC, noother alcohol seemed to have any effect on the GEBC nature. Apart from 1-propanol, 2-methyl-1-propanol was also cyanoethylated, this is not reported in the literature.
To study the diffusion of alkali into a solvent, NaOH-GEBC was stirred in a few solvents and the amount of alkali diffusing into the solvents wasmonitored (Table 2). In 2-methylpropan-2-ol, ace-tone, toluene, and dichloroethane, the diffusion ofNaOH was practically zero; however, in alcohols with increasing polarity, the diffusion increased in he order 2-propanol < ethanol < methanol. The diffusion of NaOH into ethanol medium was also studied at three different temperatures (0, 28 and78◦C); the results showed that the diffusion was temperature-independent.
In a blank experiment, the GEBC pieces were stirred in alcohol for the same time as the reaction duration and the same pieces were recycled in the subsequent
blank reactions. The amount of NaOH in ethanol was determined after each reaction. Thus, in five successive cycles, the amount of NaOH that diffused from the
GEBC was found to be 22, 7, 2, 0.6 and 0.6% of the amount of NaOH remaining after each cycle. Thus, we may say that deactivation of the catalyst is possible but
depends to a certain extent on the solvent (maximum in the case of methanol). We may also say that it goes on decreasing in each successive cycle.

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jiangguofeng

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shuoli: 金幣+100, 翻譯EPI+1, ★★★很有幫助, THANKS FOR HELP 2013-05-28 15:39:09

FOR REFERENCE ONLY

研究了不同的配方的水-NaOH-瓊脂凝膠并作出三元相圖（圖1）。得到下列各種凝膠：(1) 帶有含瓊脂固相的不均質(zhì)溶液（A型）, (2) 帶有含瓊脂固相的不均質(zhì)溶液（B型）, (3)粘性液體（C型）,(4) 膠凍狀的高粘膠（D型），（５）硬固體凝膠（E型）或（６）帶有含堿固相的不均質(zhì)溶液（F型）。某些配方是非凝膠的并且只能得到或者一種帶有大量水的簡單固體-液體混合物（B型）或者帶有很低水量的固-液混合物（A型）。 F型表示其中的堿本身是不溶于相應(yīng)量的水的配方。含有80 - 50%水:４- 24%氫氧化鈉的凝膠：  16 - 34%凍瓊脂能得到一種作為GEBC使用的硬的固體凝膠。我們選擇含有60%水, 10% NaOH和30%凍瓊脂的GEBC用于反應(yīng)。這是一種半透明的暗褐色固體（10% NaOH- GEBC）。 GEBC塊大約２毫米厚，大約３-４毫米大小不一。選擇用丙烯腈對甲醇進(jìn)行氰乙基化作為探針反應(yīng)去查找需要的GEBC的最佳最佳存貨數(shù)量（圖２）。結(jié)果發(fā)現(xiàn)10毫摩爾的丙烯腈、0.1克的GEBC于45分鐘得到100%收率的３-甲氧基丙睛。
GEBC的用量與相對于丙烯腈2.5 摩爾%的NaOH相當(dāng)。  當(dāng)使用不同尺寸的GEBC塊進(jìn)行反應(yīng)時(shí),反應(yīng)收率在實(shí)驗(yàn)誤差范圍內(nèi)是不變的。有趣的是注意到1-丙醇的氰乙基化沒有被經(jīng)典方法所報(bào)告。  2-丙醇的氰乙基化報(bào)導(dǎo)的方法是使用固體KOH作為催化劑; [1]使用這種催化劑由1-丙醇得到80%的產(chǎn)物。  另一方面，于50℃中，使用10% NaOH - GEBC，1-丙醇的氰乙基化能夠順利地進(jìn)行并得到96%的產(chǎn)物。
溶纖劑與苯甲醇也可以用NaOH-GEBC進(jìn)行氰乙基化（表1）。使用不同催化劑的經(jīng)典反應(yīng)已經(jīng)有過報(bào)導(dǎo)[２]。
   叔丁醇和異丙醇不能被氰乙化，因此用作反應(yīng)溶劑。然后研究了在10% NaOH - GEBC存在下其他醇類的氰乙基化。并且，除甲醇會(huì)引起別的方式著色的暗褐色GEBC輕微變白外,看來任何其他的醇類都不會(huì)對GEBC性質(zhì)有影響。除1-丙醇以外,異丁醇也進(jìn)行了氰乙基化,但這不是本文報(bào)告的內(nèi)容。
為了研究堿加入一種溶劑中后的擴(kuò)散作用，NaOH-GEBC于幾種溶劑中攪拌，監(jiān)測溶劑中擴(kuò)散的堿的量（表２）。于叔丁醇、丙酮、甲苯和二氯乙烷中, NaOH的擴(kuò)散作用幾乎為零;然而于極性高的醇類中,擴(kuò)散作用增大的順序依次為2-丙醇<乙醇<甲醇。 NaOH于乙醇價(jià)質(zhì)中的擴(kuò)散作用也于三個(gè)不同溫度（0，28和78℃）下進(jìn)行了研究；結(jié)果顯示擴(kuò)散作用是與溫度無關(guān)的。于一個(gè)空白試驗(yàn)中, GEBC塊于醇類中攪拌至反應(yīng)結(jié)束，隨后的空白反應(yīng)中使用同樣的GEBC塊。每次反應(yīng)后測定于乙醇中NaOH的量。這樣于五個(gè)逐次循環(huán)中,觀察到從GEBC中擴(kuò)散的NaOH的量分別是每次循環(huán)后剩余NaOH量的22, 7, 2, 0.6和0.6%。因此我們可以說催化劑的惰性化是可能的，但是在某程度上是取決于溶劑的（在甲醇的情況下為最大）。我們也可以說于每次逐次循環(huán)中擴(kuò)散的NaOH量在減少。

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2樓2013-05-28 10:04:38