第七章氧化反應(yīng)練習(xí)題

1、第七章氧化反應(yīng)練習(xí)題1. 根據(jù)以下指定原料、試劑和反應(yīng)條件，寫出其合成反應(yīng)的主要產(chǎn)物(1)CrO3CH3CO2H, 20 COIICCH3SeO2CH(CH3)2H2CQ4 丙酮CH3pcc(6) CH3CH2CHCCH2CH3 Mn2OHCF3CO3H(7) CH3CH=CHCO 2C2H5DMSO(8) (CH 3)2CHCH=CHCH=CHCH 2OH 一ClCOCOClH(9)(12)(13)(11)2) NaOHCOOH1) HCO 2H, H2O2H3C O H H2SO4CH3 MeOHH3CH2O2, CH3CNCH3OH, KHCO 3(14)1) O3KMnO4丙酮(15)

2、2) Me2SMnO 2(16)CH3(17)CANH3CCH32. 在下列指定原料和產(chǎn)物的反應(yīng)式中分別填入必需的化學(xué)試劑（或反應(yīng)物）和反應(yīng)條件。2OHPhCH=CHCH=OCHO iCCH2CO2CH3CH2CO2CH3OO(10) H2C=CHCH(OC 2H5)2 H2C CHCH(OC2H5)2OH OHOOJIu(12) Ph 一 C -CH2CH2_C PhIIPh C CH 二CHC Ph1）此反應(yīng)的完整反應(yīng)式（原料、3. 閱讀（翻譯）以下有關(guān)反應(yīng)操作的原文，請在理解基礎(chǔ)上寫出： 試劑和主要反應(yīng)條件） ；（2）此反應(yīng)的反應(yīng)機(jī)理（歷程） 。(1) Dipyridine chromi

3、um(VI) oxide (Note 1).A dry, 1-l., three-necked flask fitted with a sealed mechanical stirrer, a thermometer, and a drying tube, is charged with 500 ml. of anhydrous pyridine (Note 2), which is stirred and cooled to approximately 15 (Note 3) with an ice bath. The drying tube is periodically removed

4、and 68 g. (0.68 mole) of anhydrous chromium(VI) oxide (Note 4) is added in portions through the neck of the flask over a 30-minute period. The chromium trioxide should be added at such a rate that the temperature does not exceed 20 and in such a manner that the oxide mixes rapidly with the pyridine

5、and does not adhere to the side of the flask (Note 5). As the chromium trioxide is added, an intensely yellow, flocculent precipitate separates from the pyridine and the viscosity of the mixture increases. When the addition is complete, the mixture is allowed to warm slowly to room temperature with

6、stirring. Within one hour the viscosity of the mixture decreases and the initially yellow product changes to a deep red, macrocrystalline form that settles to the bottom of the flask when stirring is discontinued. The supernatant pyridine is decanted from the complex and the crystals are washed seve

7、ral times by decantation with 250-ml. portions of anhydrous petroleum ether. The product is collected by filtration on a sintered glass funnel and washed with anhydrous petroleum ether, avoiding contact with the atmosphere as much as possible. The complex is dried at 10 mm. until it is free-flowing,

8、 leaving 150 -60 g. (85 -91%) of dipyridine chromium(VI) oxide3 as red crystals. The product is extremely hygroscopic; contact with moisture converts it rapidly to the yellow dipyridinium dichromate.4 It is stored at 0 ina brown bottle (Note 6).(2) General oxidation procedure for alcohols.A sufficie

9、nt quantity of a 5% solution of dipyridine chromium(VI) oxide (Note 1) in anhydrous dichloromethane (Note 7) is prepared to provide a sixfold molar ratio of complex to alcohol, an excess usually required for complete oxidation to the aldehyde. The freshly prepared, pure complex dissolves completely

10、in dichloromethane at 25 at 5% concentration, giving a deep red solution, but solutions usually contain small amounts of brown, insoluble material when prepared from crude complex (Note 8). The alcohol, either pure or as a solution in anhydrous dichloromethane, is added to the red solution in one po

11、rtion with stirring at room temperature or lower. The oxidation of unhindered primary (and secondary) alcohols proceeds to completion within 5 to 15 minutes at 25with deposition of brownish-black, polymeric, reduced chromium -pyridine products (Note 9). When deposition of reduced chromium compounds

12、is complete (monitoring the reaction by GC or TLC is helpful), the supernatant liquid is decanted from the (usually tarry) precipitate, which is rinsed thoroughly with dichloromethane (Note 10). The combined dichloromethane solutions may be washed with dilute hydrochloric acid, sodium hydrogen carbo

13、nate solution, and water, or filtered directly through a filter aid, or passed through a chromatographic column to remove traces of pyridine and chromium salts. The product is obtained by removal of dichloromethane; any pyridine that remains can often be removed under reduced pressure.(3) Heptanal.A

14、 dry, 1-l. three-necked round-bottomed flask is equipped with a mechanical stirrer, and 650 ml. of anhydrous dichloromethane (Note 7) is added. Stirring is begun and 77.5 g. (0.300 mole) of dipyridine chromium(VI) oxide (Note 1) is added at room temperature, followed by 5.8 g. (0.050 mole) of 1-hept

15、anol (Note 11) in one portion. After stirring for 20 minutes, the supernatant solution is decanted from the insoluble brown gum, which is washed with three 100-ml. portions of ether. The ether and dichloromethane solutions are combined and washed successively with 300 ml. of aqueous 5% sodium hydroxide, 100 ml. of 5% hydrochloric acid (Note 12), two 100-ml. portions of saturated aqueous sodium hydrogen carbonate, and, finally, with 100 ml. of saturated aqueous sodium chloride. The organic layer is dried