Who can provide a paper on the preparation of benzylidene acetophenone? I need to do my homework ~ The principle is that benzaldehyde and acetophenone are synthesized under alkaline conditions. Thank you~ Chalcone is widely used in medicine and daily chemicals. The classical synthesis method of chalcone is to catalyze the condensation of benzaldehyde and acetophenone aldol with strong alkali sodium hydroxide or potassium hydroxide in ethanol aqueous solution and dehydrate it. In recent years, solvent-free solid-state organic reactions have attracted much attention because of their high reaction efficiency, simple operation and environmental friendliness. In 1990, the aldol condensation of substituted benzaldehyde and acetophenone catalyzed by sodium hydroxide in the absence of solvent was reported for the first time, and the corresponding chalcone was obtained in high yield. In 1997, ball milling technology is used to further improve the efficiency of organic solid-state reaction and overcome the shortcoming that reaction substrates can not be fully contacted. In the absence of solvent, the solid-phase aldol condensation reaction of substituted benzaldehyde and acetophenone was promoted with the mixed alkali of sodium hydroxide and potassium carbonate as catalyst. The results show that the reaction time is obviously shortened and the yield can reach 90% ~ 98%. Ar1CHO1Ar2coch32NaOH/K2CO3 ball milling Ar1CHCHCHCOAR 23A ~ 3G, 76g (0.05mol) of p-nitrobenzaldehyde, 60g (0.05mol) of acetophenone, 0.2g (0.005mol) were mixed. After sodium hydroxide and 3 5g potassium carbonate (0.025mol) are fully mixed, start the ball mill, react for 8min, and then pour 50mL distilled water into the ball mill. See table 1 for other filtration results.

Table 1 Synthesis Results of Compounds 3a ~ 3g

This kind of instrument needs special blowing, but the blowing is not very difficult, and it can be done by ordinary glass instrument factories. Need to be reminded that when blowing, the channel of the branch pipe must be larger to make the steam smoother. At the same time, if the upper and lower interfaces of the instrument can be polished into standard grinding ports in the production process to match the grinding devices commonly used in the laboratory, such as distillation bottles and condensation tubes, the instrument will be quite convenient to use in the laboratory.

(School of Chemistry and Environmental Sciences, Hebei University, Baoding, Hebei 07 1002)

Under ultrasonic irradiation, benzaldehyde and acetophenone reacted at 25 ~ 30℃ for 30 ~ 35 min under the catalysis of sodium hydroxide, and the yield of benzylidene acetophenone was 87%. This is a sonochemical experiment suitable for undergraduates. Keywords: benzylidene acetophenone; Synthesis; Classification number of pictures in sonochemical experiment: Q787 Document ID: B ArticleNo.:1006-7167 (2003) 01-0050-02 Improvement of ultrasonic synthesis of benzoacetophenone Hua, Tai *, Yang Wenzhi, Wen (Chemistry and Environment, Hebei University Abstract: The condensation reaction of benzaldehyde and acetophenone took 30 ~ 35 minutes at 25 ~ 30℃, and the yield was 87%. This is an organic synthesis and chemical experiment for undergraduates. Keywords: benzylidene acetophenone, synthesis, sonochemical experiment

Since 1980s, with the development of sonochemistry, the application of ultrasonic radiation (U.S) in organic synthesis has developed vigorously, which is widely used in oxidation, reduction, substitution, condensation and hydrolysis, involving almost all fields of organic reactions. According to the characteristics of ultrasonic radiation, we try to introduce ultrasonic radiation technology into the undergraduate organic chemistry experiment, and improve the synthesis of benzylidene acetophenone (1), so that students can understand the background of this interdisciplinary subject, master the specific operation of using ultrasonic to carry out organic reactions, and have a deeper understanding of the changes brought by ultrasonic radiation technology to the synthesis of fine chemicals such as pesticides and drugs based on organic synthesis. C6H5CHO+CH3CC6H5NaOH (10%), Etohu S.25 ~ 30CCHC6H5CC6H5h (1) In reference [7], benzylidene acetophenone was synthesized by the condensation of benzaldehyde and acetophenone catalyzed by10% sodium hydroxide solution. In order to make the reaction smoothly and control the dropping speed of benzaldehyde, it is usually carried out in a three-necked bottle equipped with a stirrer, a thermometer and a dropping funnel. The reaction time from dropping benzaldehyde to adding seed crystal and continuously stirring the reaction flask was 65438±0.5 ~ 2.0h, and the yield was 67 ~ 72%. Under ultrasonic radiation, as long as the medicine and the catalyst are added into the conical flask in turn, they are put into an ultrasonic cleaner for ultrasonic radiation for 35 minutes. And the crystals were precipitated in the reaction flask. After washing with cold ethanol, better crystals can be obtained, the melting point is 56 ~ 57℃, and the average yield in students' experiments is 87%. When arranging experiments, in order to enable students to compare the effects of classical method and ultrasonic method in time, we asked a group of two students to operate equipment and instruments according to the classical method, add drugs, and start the experiment of ultrasonic method after all the required benzaldehyde was dropped into a three-necked bottle and stirred for 0.5h The actual effect is that after the reaction under ultrasonic radiation, the classical reaction continues. Students obviously feel that ultrasonic radiation accelerates the reaction speed and shortens the reaction time, and the operation and device are simple. Under the action of ultrasonic wave, the dosage of catalyst sodium hydroxide is reduced by 1/2 compared with the classical method. The same effect can be obtained when potassium hydroxide is used instead of sodium hydroxide for catalysis. It should be mentioned that if the amount of alkali is too large, a large number of polymers will be formed in the reaction, and the yield of the corresponding condensate will be reduced. Through the synthesis of benzylidene acetophenone, comparing the classical method with ultrasonic radiation method, it can be clearly observed that ultrasonic radiation method not only has simple equipment, simple operation, fast reaction speed and high yield, but also reduces the amount of catalyst.