【摘要】：ε-己內(nèi)酯是合成眾多化工產(chǎn)品的有機中間體和聚合物單體,有著極其廣泛的應(yīng)用。目前,工業(yè)上生產(chǎn)ε-己內(nèi)酯主要是以過氧酸氧化環(huán)己酮的Baeyer-Villiger氧化反應(yīng),該工藝存在高爆炸性和副產(chǎn)羧酸等缺點。因此,采用環(huán)境友好的低濃度H2O_2(30%)代替?zhèn)鹘y(tǒng)的過氧酸作為氧化劑,更符合綠色化學(xué)的發(fā)展理念,開發(fā)高效的催化劑成為環(huán)己酮Baeyer-Villiger氧化反應(yīng)制備ε-己內(nèi)酯的關(guān)鍵性技術(shù)。本論文首先以NaY分子篩為載體,以SnCl_4?5H_2O為錫源,采用離子交換法制備了Sn-NaY,考察了錫源加入量、溫度和時間對催化劑結(jié)構(gòu)及活性的影響。采用FT-IR、UV-Vis、XRD和N_2物理吸附等手段進行了表征。結(jié)果表明,隨著錫源加入量的增加,生成了更多的骨架外SnO_2,且酸度增加造成了NaY分子篩結(jié)構(gòu)的破壞。隨著交換時間的延長,形成更多四配位Sn4+,當(dāng)交換時間超過8h時,交換達到平衡,Sn的含量不會增加。通過環(huán)己酮的Baeyer-Villiger氧化反應(yīng)對催化劑活性進行評價,得出較優(yōu)的離子交換條件為:載體與錫源之比為3:1,交換溫度為80℃,交換時間為8h。其次,采用CVD法對NaY分子篩負載金屬Sn,考察了鹽酸脫鋁、水熱脫鋁和(NH_4)__2SiF_6液相同晶取代法脫鋁三種方式對NaY分子篩脫鋁改性結(jié)構(gòu)及CVD法負載金屬Sn后催化劑性能的影響。通過各種手段對催化劑樣品的比表面積、孔容和孔徑、孔骨架結(jié)構(gòu)等進行了測定,通過以H2O_2為氧源的環(huán)己酮的Baeyer-Villiger氧化反應(yīng)對催化劑的催化性能進行了評價。結(jié)果表明,水熱法脫鋁改性NaY效果最好,CVD負載金屬Sn后環(huán)己酮的轉(zhuǎn)化率為43.7%,己內(nèi)酯的選擇性為41.5%。最后,選用無定型介孔二氧化硅為載體,SnCl4為錫源,通過化學(xué)氣相沉積法制備了Sn/Si O_2。系統(tǒng)考察了CVD過程中前處理、溫度和時間及焙燒氛圍和焙燒溫度對催化劑的影響,通過FT-IR、UV-Vis、N2物理吸附、ICP和NH_3-TPD對催化劑的結(jié)構(gòu)進行了表征。結(jié)果表明,對載體進行水熱處理,可以增加Si-OH的數(shù)量,有利于CVD負載過程生成更多的骨架Sn;在N_2氛圍中進行焙燒處理,可以防止骨架外的Sn組分被氧化生成SnO_2。進一步通過以H2O_2為氧源的環(huán)己酮的Baeyer-Villiger氧化反應(yīng)評價催化劑的催化性能,得出較優(yōu)的CVD法制備Sn/SiO_2的條件為:對載體進行焙燒處理,CVD溫度540℃,時間1.5h,在N_2氛圍中焙燒,焙燒溫度為300℃。
[Abstract]:蔚-caprolactone (蔚-caprolactone) is an organic intermediate and polymer monomer for the synthesis of many chemical products. At present, the industrial production of 蔚-caprolactone is mainly due to the Baeyer-Villiger oxidation of cyclohexanone with peroxic acid, which has the disadvantages of high explosive and by-product carboxylic acid. Therefore, the use of environmentally friendly low concentration H2O_2 (30%) instead of the traditional peroxic acid as an oxidant, is more in line with the concept of green chemistry development. The development of efficient catalysts has become the key technology for the preparation of 蔚-caprolactone by Baeyer-Villiger oxidation of cyclohexanone. Firstly, using NaY as carrier and SnCl_4?5H_2O as tin source, Sn-NaY, was prepared by ion exchange method. The effects of the amount of tin source, temperature and time on the structure and activity of the catalyst were investigated. The results were characterized by FT-IR,UV-Vis,XRD and N _ (2) O _ (2) physisorption. The results show that with the increase of the amount of tin source, more extra-skeleton SnO_2, is formed and the structure of NaY molecular sieve is destroyed by the increase of acidity. With the prolongation of the exchange time, more four-coordinated Sn4 was formed. When the exchange time was longer than 8 hours, the exchange reached equilibrium, and the content of Sn did not increase. The activity of the catalyst was evaluated by Baeyer-Villiger oxidation of cyclohexanone. The optimum ion exchange conditions were as follows: the ratio of carrier to tin source was 3? 1, the exchange temperature was 80 鈩，

本文編號：2432461