《有机化学实验》教材思考题答案[1].doc

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1、实验一 常压蒸馏及沸点的测定1、解：当液体混合物受热时，其蒸汽压随之升高。当与外界大气压相等时，液体变为蒸汽，再通过冷凝使蒸汽变为液体的两个联合操作的过程叫蒸馏。从安全和效果方面考虑，蒸馏实验过程中应注意如下几点。待蒸馏液的体积约占蒸馏烧瓶体积的1/32/3。沸石应在液体未加热前加入。液体接近沸腾温度时，不能加入沸石，要待液体冷却后才能加入，用过的沸石不能再用。待蒸馏液的沸点如在140以下，可以选用直形冷凝管，若在140以上，则要选用空气冷凝管。蒸馏低沸点易燃液体时，不能明火加热，应改用水浴加热。蒸馏烧瓶不能蒸干，以防意外。2、解：（1）温度控制不好，蒸出速度太快，此时温度计的显示会超过79，

2、同时馏液中将会含有高沸点液体有机物而至产品不纯，达不到蒸馏的目的。（2）如果温度计水银球位于支管口之上，蒸气还未达到温度计水银球就已从支管流出，测定沸点时，将使数值偏低。若按规定的温度范围集取馏份，则按此温度计位置收集的馏份比规定的温度偏高，并且将有少量的馏份误作前馏份而损失，使收集量偏少。 如果温度计的水银球位于支管口之下，测定沸点时，数值将偏高。但若按规定的温度范围收集馏份时，则按此温度计位置收集的馏份比要求的温度偏低，并且将有少量的馏份误认为后馏份而损失。3、解：(1)沸石的作用：沸石为多孔性物质，它在溶液中受热时会产生一股稳定而细小的空气泡流，这一气泡流以及随之而产生的湍动，能使液体中

3、的大气泡破裂，成为液体分子的气化中心，从而使液体平稳地沸腾，防止了液体因过热而产生的暴沸。简而言之，是为了防止暴沸！ (2)如果加热后才发现没加沸石，应立即停止加热，待液体冷却后再补加，切忌在加热过程中补加，否则会引起剧烈的暴沸，甚至使部分液体冲出瓶外而引起着火。4、解：中途停止蒸馏，再重新开始蒸馏时，因液体已被吸入沸石的空隙中，再加热已不能产生细小的空气流而失效，必须重新补加沸石。5、解：应立即停止加热。（1）冷却后补加新的沸石。用过的沸石一般不能再继续使用，因为它的微孔中已充满或留有杂质，孔径变小或堵塞，不能再起助沸作用。（2）如有馏液蒸出来，则须等到冷凝管冷却后再通水。因为冷凝管骤冷会爆

4、裂。实验二 分馏1、解：蒸馏可用于沸点相差较大或分离要求不高的液体混合物的分离。分馏主要用于相差较小或分离要求较高的液体混合物的分离。两者在原理上是相同的，分馏相当于多次蒸馏。除了应用范围不同外，它们的装置也不同，分馏装置比蒸馏装置多了一个分馏柱。它们在操作上馏出速度也不同，蒸馏操作馏出速度尾12滴/s，而分馏馏出速度为1滴/（23）s。2、解：不可以。如果把分馏柱顶上温度计的水银柱的位置向下插些，这样测定沸点时，数值将偏高。但若按规定的温度范围集取馏份时，则按此温度计位置集取的馏份比要求的温度偏低，并且将有少量的馏份误认为后馏份而损失。3、解：加热过快，馏液滴数增加，使得上升的蒸汽来不及热交

5、换就直接进入冷凝管，所以分离能力会下降。4、解：这样可以保证上面冷凝下来的液体与下面上升的气体进行充分的热交换和质交换，提高分离效果。5、解：填充物在柱中起到增加蒸汽与回流液接触的作用，填充物比表面积越大，越有利于提高分离效率。所以有填充物的柱比不装填料的效率高。实验三 重结晶1、解：一般包括：（1）选择适宜溶剂，目的在于获得最大回收率的精制品。（2）制成热的饱和溶液。目的是脱色。（2）热过滤，目的是为了除去不溶性杂质（包括活性炭）。（3）晶体的析出，目的是为了形成整齐的晶体。（4）晶体的收集和洗涤，除去易溶的杂质，除去存在于晶体表面的母液。（4）晶体的干燥，除去附着于晶体表面的母液和溶剂。2

6、、解：控制溶剂用量，利于配制饱和溶液。3、解：应注意：(1)加入活性炭要适量，加多会吸附产物，加少，颜色脱不掉；用量为固体重量的15%为合适。(2)不能在沸腾或接近沸腾的温度下加入活性炭，以免暴沸；(3)加入活性炭后应煮沸几分钟后才能热过滤。4、解：如果滤纸大于漏斗瓷孔面时，滤纸将会折边，那样滤液在抽滤时将会自滤纸边沿吸入瓶中，而造成晶体损失。所以不能大，只要盖住瓷孔即可。5、解：与第一次析出的晶体相比，纯度下降。因为母液中杂质的浓度会更高，所以结晶产品中杂质含量也相对较高。6、解：注意：（1）边加热边趁热过滤。要不时加热大烧杯。（2）热滤滤纸不能有缺口。热滤时要沉着冷静，不要让活性炭从滤纸边

7、缘掉到锥形瓶里。（3）总的溶液不能超过120ml。否则产率降低。（4）注意挤干晶体。否则产率虚高。7、以内的固体，可视为纯净。实验四 减压蒸馏1、 解：液体的沸点随外界压力的降低而降低。在低于大气压力下进行的蒸馏称为减压蒸馏。减压蒸馏主要应用于：纯化高沸点液体；分离或纯化在常压沸点温度下易于分解、氧化或发生其它化学变化的液体；分离在常压下因沸点相近二难于分离，但在减压下可有效分离的液体混合物；分离纯化低熔点固体。2、解：装配要求：系统不漏气，压力稳定，平稳沸腾。应注意：减压蒸馏时应用克氏蒸馏头，带支管的接液管或使用多头接液管。需用毛细管代替沸石，防止暴沸。要求用热浴加热，需使用厚壁耐压的玻璃仪

8、器。*3、解：必须先抽真空后加热，对于油泵，原因是：系统内充满空气，加热后部分溶液气化，再抽气时，大量气体来不及冷凝和吸收，会直接进入真空泵，损坏泵改变真空度。如先抽气再加热，可以避免或减少之。 对于水泵：防止由于“过热”引起的暴沸。必须用热浴加热：用热浴的好处是加热均匀，可防止暴沸，如果直接用火加热的话，情况正好相反。*4、解：略*5、解：蒸馏完毕移去热源，慢慢旋开螺旋夹，并慢慢打开二通活塞，（这样可以防止倒吸），平衡内外压力，使测压计的水银柱慢慢地回复原状（若放开得太快，水银柱很快上升，有冲破压力计的可能）然后关闭油泵和冷却水。实验五 仪器操作实验无作业！熔点的测定1、解：130139熔化

9、。A与C是同一物质。2、解：将样品与已知化合物按一定比例（通常取11，91，19）混合后，测定混合物的熔点。若为两种不相同的化合物，则熔点下降，熔程变宽。如果是相同化合物，则熔点不变。折光率的测定1、解：通过测定折光率可以判断有机物的纯度、鉴定未知有机物以及在分馏时配合沸点，作为切割馏分的依据。2、解：旋光度的测定1、 解：方法一：将溶液稀释一倍，如果其旋光度为+15，则证明原来溶液的旋光度为+30。 方法二：采用20cm的试管，如果其旋光度为+60，则证明原来溶液的旋光度为+30。2、解：3、解：应注意：（1）注意看看试管中有无气泡。（2）试管安放时应注意标记试管的位置和方向。（3）仪器使用

10、时间不宜过长。一般不超过4小时，但实验中间不需关闭电源。（4）所有镜片不得用手擦拭，应用擦镜纸擦拭。实验六 水蒸气蒸馏1、解：插入容器底部的目的是使瓶内液体充分加热和搅拌，有利于更有效地进行水蒸汽蒸馏。2、解：经常要检查安全管中水位是否正常，若安全管中水位上升很高，说明系统有堵塞现象，这时应立即打开止水夹，让水蒸汽发生器和大气相通，排除故障后方可继续进行蒸馏。3、解：在分液漏斗中加入一些水，体积增大的那一层是水层，另一层是有机层。实验七 乙酸乙酯的制备1、解：催化剂和脱水剂。说明：硫酸的用量为醇用量的3%时即起催化作用。当硫酸用量较多时，它又起脱水作用而增加酯的产率。但当硫酸用量过多时，由于它

11、在高温时会起氧化作用，结果对反应反而不利。本实验用了5ml硫酸，硫酸已经过量了。2、解：可逆反应，需酸催化。方法有：(1)提高反应物之一的用量；(2)减少生成物的量(移去水或酯)；(3)催化剂浓硫酸的用量要适当(太少，反应速度慢，太多，会使副产物增多，但不影响产率)。3、解：饱和氯化钙溶液可以除去未反应的乙醇。当酯层用碳酸钠洗过后，若紧接着就用氯化钙溶液洗涤，有可能产生絮状的碳酸钙沉淀，使进一步分离变得困难，故在这两步操作之间必须水洗一下。由于乙酸乙酯在水中有一定的溶解度，为了尽可能减少由此而造成的损失，采用“盐析效应”，所以实际上用饱和食盐水进行水洗。（参见教材P40，盐析效应）实验八 乙酸

12、正丁酯的制备1、解：可能的副反应：提高产率的方法有：(1)提高反应物之一的用量；(2)减少生成物的量(移去水或酯)。2、解：不可以。因为开始加热蒸馏出来的乙醇与水互溶后，使分水器中的水倒灌进入烧瓶，导致产率大大降低。*3、解：分水器的作用就是除去反应过程中生成的水，使反应向生成物的方向进行，提高反应产率。带水剂的作用就是与水形成饱和蒸气压，将水带出来；同时也可以降低反应温度，使反应平稳进行。*4、解：方法有：沸点、折光率、气相色谱等的测定。*5、解：见实验报告。实验九 1-溴丁烷的制备1、解：副反应有：减少副反应的方法：（1）注意加料顺序。切不可颠倒！（2）加热溶解过程中，要不断摇动。这样可以

13、扩大固液接触面，加快反应速度。2、解：油层若呈红棕色，说明含有游离的溴。可用少量亚硫酸氢钠水溶液洗涤以除去游离溴。反应方程式为：Br2+NaHSO3 +H2O 2HBr + NaHSO42、 解：碳酸钠溶液可以除去HBr、Br2等杂质。水洗涤是除去碳酸钠溶液。实验十 醋酸乙烯酯乳液聚合-白乳胶的制备1、解：3、解：引发剂包括油溶性和水溶性两种。本体、溶液、悬浮聚合时，选用油溶性引发剂。乳液聚合则选用水溶性引发剂。 油溶性引发剂有过氧化苯甲酰、偶氮异丁腈等。水溶性引发剂有过硫酸盐等。（英文版 ） Two regulations promulgated for implementation is

14、in the party in power for a long time and the rule of law conditions, the implementation of comprehensive strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party supervision of major initiatives. The two regulations supporting e

15、ach other, the adhere to a positive advocate, focusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; around the party discipline, disciplinary ruler requirements, listed as negative list, focusing on vertical gauge, draw the party organizations and

16、Party members do not touch the bottom line . Here, the main from four square face two party rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the interpretation of the two fundamental principles of the revision

17、 of laws and regulations in the party; the third part introduces two party regulations modified the main changes and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the party. and revised the necessity and revised history of the CPC C

18、entral Committee the amendment to the Chinese Communist Party members and leading cadres honest politics several guidelines and column 1 by 2015 to strengthen party laws and regulations focus. Two party regulations revision work lasted a Years, pooling the wisdom of the whole party, ideological cons

19、ensus, draw historical experience, respect for the wisdom of our predecessors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the partys leadership, to solve the masses of the people reflect a focus on the problem. The new rev

20、ision of the and , reflects the partys 18 and the eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech, reflects the partys eighteen years comprehensive strictly pract

21、ice. (a) revised two regulations of the party need of in based on revised, the promulgation and implementation of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the party to manage the party strictly administering the deepening, has

22、not been able to fully meet the actual needs. Content is too complicated, eight prohibition, 52 are not allowed to hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of prohibited provisions excessive, no autonomy requirements; the third

23、 is banned terms and discipline law, both with the party discipline, disciplinary regulations repeat and Criminal law and other laws and regulations repeat; the fourth is to clean the theme is not prominent, not for the existing problems, and is narrow, only needle of county-level leading cadres abo

24、ve. is in 1997 based on revision, in December 2003 the promulgation and implementation, to strengthen the construction of the party play very important role. Along with the development of the situation, which many provisions have been unable to fully meet the comprehensive strictly administering the

25、 practice needs. One is Ji law, more than half of the provisions and criminal law and other countries laws and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the party constitution, damage the authority of Party Constitution of mi

26、sconduct lack necessary and serious responsibility to pursue; third is the main discipline for the leading cadres, does not cover all Party members. Based on the above situation, need to and the two is likely to be more relevant regulations first amendment. By revising, really put the authority of P

27、arty discipline, the seriousness in the party tree and call up the majority of Party members and cadres of the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee of the Communist Party of China attaches great importance to two

28、 regulations revision . Xi Jinping, general books recorded in the Fifth Plenary Session of the eighth session of the Central Commission for Discipline Inspection, on the revised regulations made clear instructions. According to the central deployment, the Central Commission for Discipline Inspection

29、 from 2014 under six months begin study two regulations revision. The Standing Committee of the Central Commission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations revision, amendment clarifies the direction, major issues of pri

30、nciple, path and target, respectively held a forum will listen to part of the province (area) secretary of the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs Department The first party committee is mainly responsible for people, vi

31、ews of experts and scholars and grassroots party organizations and Party members. Approved by the Central Committee of the Communist Party of China, on 7 September 2015, the general office of the Central Committee of the Party issued a notice to solicit the provinces (autonomous regions, municipalit

32、ies) Party, the central ministries and commissions, state ministries and commissions of the Party (party), the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Central Commission for Discipline Inspection of extensive solicitatio

33、n of opinions, careful study, attracting, formed a revised sent reviewers. In October 8 and October 12, Central Committee Political Bureau Standing Committee and the Political Bureau of the Central Committee After consideration of the two regulations revised draft. On October 18, the Central Committ

34、ee of the Communist Party of China formally issued two regulations. Can say, two laws amendment concentrated the wisdom of the whole party, embodies the party. Second, and revision of the basic principles of two party regulations revision work and implement the partys eighteen, ten eight plenary, th

35、e spirit of the Fourth Plenary Session of the Eleventh Central Committee and General Secretary Xi Jinping important instructions on the revised and , highlighting the ruling party characteristics, serious discipline, the discipline quite in front of the law, based on the current, a long-term, advanc

36、e as a whole, with Bu Xiuding independent and . Main principle is: first, adhere to the party constitution to follow. The constitution about discipline and self-discipline required specific, awaken the party constitution of party compasses party consciousness, maintaining the authority of the consti

37、tution. General Secretary Xi Jinping pointed out that no rules, no side round. Party constitution is the fundamental law, the party must follow the general rules. In early 2015 held the eighth session of the Central Commission for Discipline Inspection Fifth Plenary Session of the 16th Central Commi

38、ttee, Xi Jinping again pointed out that constitution is the party must follow the general rules, but also the general rules. the revision of the and is Method in adhere to the regulations established for the purpose of combining rule of virtue is to adhere to the party constitution as a fundamental

39、to follow, the constitution authority set up, wake up the party constitution and party rules the sense of discipline, the party constitution about discipline and self-discipline specific requirements. 4 second is to adhere to in accordance with the regulations governing the party and the party. The

40、Party of rule of virtue de, mainly refers to the partys ideals and beliefs, excellent traditional style. The revised the closely linked to the self-discipline, insisting on the positive initiative, for all members, highlight the vital few, emphasized self-discipline, focusing on the morality, and th

41、e majority of Party members and the ideological and moral standards. The revised Ji method separately, Ji, Ji Yan to Method, as a negative list, emphasizing the heteronomy, focusing on vertical gauge. Is this one high and one low, a positive reaction, the strict party discipline and practice results

42、 transformation for the integration of the whole party to observe moral and discipline requirements, for the majority of Party members and cadres provides benchmarking and ruler. Third, insist on to. In view of the problems existing in the party at the present stage, the main problems of Party membe

43、rs and cadres in the aspect of self-discipline and abide by the discipline to make clearly defined, especially the partys eighteen years strict political discipline and political rules, organization and discipline and to implement the central eight provisions of the spirit against the four winds and

44、 other requirements into Disciplinary provisions. Not one pace reachs the designated position, focusing on in line with reality, pragmatic and effective. After the revision of major changes, major changes in the and modified and needs to grasp several key problems (a) adhere to according to regulati

45、ons governing the party and party with morals in combination, for at the present stage, the leadership of the party members and cadres and Party members in existing main problems of self-discipline, put forward principles, requirements and specifications, showing Communists noble moral pursuit, refl

46、ected at all times and in all over the world ethics from high from low 5 common requirements. One is closely linked to the self-discipline, removal and no direct relation to the provisions of . the second is adhere to a positive advocate, eight prohibition 52 are not allowed to about the content of

47、the negative list moved into synchronization amendment . Three is for all the party members, will apply object from the leadership of the party members and cadres to expand to all Party members, fully embodies the comprehensive strictly required. The fourth is prominent key minority, seize the leadership of the party members and cadre