高纯度1,1,3-三氯丙酮的制备

丙酮经催化氯化,再通过溶剂结晶制得含量不低于99.0%的高纯度1,1,3-三氯丙酮结晶,其收率为45%。     

医药中间体糠叉丙酮合成条件的探讨

以呋喃醛 (糠醛 )为原料 ,在水 -氢氧化钠体系中合成了糠叉丙酮 ,探讨了丙酮用量 ,氢氧化钠浓度对反应的影响     

香料紫罗兰酮的合成

在45%氢氧化钠溶液和高速搅拌条件下,以柠檬醛为原料与丙酮缩合制取假性紫罗兰酮,后者在苯和60%硫酸溶液的作用下,环化得紫罗兰酮.本文还探讨了缩合反应时间和丙酮用量对反应产率的影响,得到最佳合成条件:缩合反应时间为3小时,丙酮用量为45ml,紫罗兰酮的产率为23.31%.     

乙醚与丙酮燃烧反应机理

利用公式△H=-0．1196n／A计算了乙醚和丙酮分别在氧气和空气中燃烧反应的温度,并推测了乙醚和丙酮燃烧反应的机理．乙醚在氧气中燃烧反应的火焰温度理论值为3272K,与测定温度3134K接近,误差为4．40％．丙酮在空气中燃烧反应的火焰温度理论值为1292K,与测定温度173K接近,误差为1．49％．根据乙醚和丙酮燃烧反应的火焰温度,推测乙醚和丙酮燃烧反应机理为：（1）O2＋hv→2O·;（2）（C2H5）2O→4C＋4H2＋H2O（乙醚）,CH3COCH3→3C＋2H2＋H2O（丙酮）;（3）H2＋O·→H2O＋hv;（4）C＋O·→CO＋hv;（5）2CO＋O2→2CO2．     

关于乙醇、乙醛和丙酮的区别

“怎样区别乙醇、乙醛和丙酮?”是中学化学常见的一个习题。有时把答案写成:“与钠反应能产生氢气的为乙醇;发生银镜反应的是乙醛;余下的一种为丙酮。”这与实际情况是不相符的,因为乙醛与丙酮也能与金属钠反应。     

头孢哌酮钠中有机溶剂残留量的测定

建立了采用直接进样毛细管气相色谱法测定头孢哌酮钠中丙酮和正丁醇残留量的方法.色谱柱为DB-1石英毛细管柱,柱温为150℃,载气为氮气,检测器为FID,以DMF为溶剂.在上述色谱条件下,丙酮和正丁醇的线性范围为10~90 mg/L,平均加样回收率分别为100.53%和99.28%.本方法简便、专属性强、准确度高,可用于测定原料药中丙酮和正丁醇的残留量.     

相转移催化下的交叉羟醛缩合反应

以PEG－400为相转移催化剂，用于苯甲醛与丙酮之间的交叉羟醛缩合反应，合成了二亚苄基丙酮，产率达91％。     

正交法研究虎杖白藜芦醇提取工艺

采用正交实验法,以提取物中白藜芦醇的提取率为评价指标,研究虎杖白藜芦醇的最佳提取分离工艺。结果表明：丙酮为提取剂的最佳提取工艺是100％／丙酮,液料比为1：20,温度为40℃,时间为36h,虎杖中白藜芦醇提取率可达0．950％。     

探究丙酮导致鲢鱼死亡的半致死浓度

1提出问题丙酮易挥发,而且有毒性。那么丙酮对鲢鱼究竟有多大影响呢?丙酮导致鲢鱼死亡的半致死浓度又是多少呢?2作出假设丙酮导致鲢鱼死亡的半致死浓度非常低。3设计实验3.1材料用具鲢鱼若干条(大小基本一致,身体状况良好);丙酮;长、宽、高分别为40cm、40cm、50cm的玻璃容器,量筒,移液管,洗耳球,鱼网,量杯,玻璃棒,计数器等。     

无皂高分子纳米乳胶粒子稳定性研究

采用微波法,以MMA、ST为单体,KPS为引发剂,不同配比的丙酮水溶液作为分散介质进行无皂乳液聚合,得到了稳定的高分子纳米胶乳粒子.对无皂乳液的电解质稳定性、冻融稳定性和机械稳定性进行研究,结果表明乳液中加入丙酮可以改善其各种稳定性.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…