【作者】 龙海平；

【导师】 黎学明；

【作者基本信息】 重庆大学 ， 物理化学， 2009， 硕士

【摘要】 甲烷是易燃易爆气体,是矿井瓦斯主要成分,瓦斯爆炸易引起重大经济损失和安全事故。因此,对矿井中甲烷进行监测十分必要。目前,矿井甲烷监测主要有热催化燃烧型、气敏半导体型、红外吸收型和光干涉型瓦斯传感器,但它们有检测周期长、精度差、易中毒、维护不便等明显不足。因此,研究一种安全、可靠、高灵敏度的甲烷传感系统具有重大现实意义。笼形超分子材料是一类重要的新材料,其在生命科学、材料科学、分子电子学、传感器等领域具有重要作用。近年来研究发现,笼形超分子材料Cryptophane A和E对甲烷敏感,有望将它们用于新一代甲烷传感器。采用三步法合成Cryptophane A和E;通过核磁共振、紫外吸收和荧光光谱等技术表征其结构和理化性质;设计制作纤芯失配型光纤甲烷传感器,评价传感性能;探讨Cryptophane A和E对甲烷敏感机理。取得如下结论:（1）综述国内外甲烷气体监测技术应用现状,新型矿井瓦斯监测技术研究情况,Cryptophanes A和E合成方法及其甲烷敏感特性研究进展。（2）以香草醛为原料采用三步法合成Cryptophane A和E,得到最终合成产率分别为3.08%和9.79%。最优合成和分离工艺为:第一步,香草醛过量,80℃下回流22h;1,2-二（4-甲酰-2-甲氧基苯氧基）乙烷分离先用溶剂溶解固体,然后抽滤、真空干燥,1,3-二（4-甲酰-2-甲氧基苯氧基）丙烷分离经重结晶、抽滤、真空干燥;第二步,缓慢多次加入NaBH₄(M_NaBH4 /M_compound2=6:1),60℃下回流25h,反应完全后用稀HCl和甲醇/水溶液（体积比为1:1）充分洗涤抽滤;第三步,甲酸（90%）中70℃下回流4h,并蒸干,经CH₂Cl₂萃取,最后硅胶色谱柱过柱(V_二氯甲烷/V_丙酮=10:1)。（3）核磁表征中4.41（d, 6H, CH_a）、3.41（d, 6H, CH_e）及36.78(C_a,e)的存在证明成功合成了Cryptophane A;而4.65（d, 6H, CH_a）、3.43（d, 6H, CH_e）及36.13(C_a,e)则证明成功合成了Cryptophane E。Cryptophane A和E最大荧光发射波长分别在440nm和435nm。在CH₂Cl₂溶剂中,Cryptophane A和E紫外吸收峰分别在λ₁=236nm,λ₂=284nm和λ₁=234nm,λ₂=286nm。（4）甲烷光纤传感器敏感实验结果表明,最佳入射角为15°,对Cryptophane A长度为3mm的传感器其响应灵敏度好,而对Cryptophane E,长度为8mm的效果好;敏感膜的吸附和解吸时间约80s。更多还原

【Abstract】 Methane is an inflammable and explosive gas, it’s the main constituent of the mine gas. Fire damp explosion usually lead to magnitude economic losses and safety accidents. And therefore it’s necessary to monitor the content of methane in mine gas. At present, sensors used to detect methane in mine gas mainly based on thermo catalytic, gas sensory semiconductor, infrared absorption and light-interference types. But these kind of sensors have long testing period, poor accuracy, prone to be poisoned, inconvenient maintenance and other shortages. Thus, develop a safe, reliable and high sensitivity methane sensory system is of great practical meaning. Cryptophanes are an important new type material, they play an important role in life sciences, material sciences, molecular electronics, sensors and other fields. It’s detected in recent years that Cryptophane A and Cryptophane E are sensitive to methane, and they are promising to be used in next new generation methane sensors.Cryptophane A and E were prepared from vanillin via a three-step method. Their structures were characterized by means of ¹H NMR, ¹³C NMR, UV, fluorescence spectra etc. A fiber-core mismatch fiber methane sensor was designed and built, and methane sensing mechanisms of Cryptophane A and E were discussed. Main results of the thesis are as follows:（1） The application of methane monitoring technologies, development of new type mine gas monitoring technologies, synthesis of Cryptophane A and E and their sensing characteristics to methane both internal and abroad were reviewed respectively.（2） Cryptophane A and E were prepared from vanillin via a three-step method, and the yields were 3.08% and 9.79% at the optimal synthesis and isolation technology. The optimal synthesis and isolation technology was as follows: firstly, 1,2-bis（4-formyl-2-methoxyphenoxy） ethane, 1,3-bis（4-formyl-2-methoxyphenoxy） propane were prepared with excess vanillin and refluxed for 22h at 80℃, and they were used respectively to dissolve and recrystal the yields, filtered and vacuum dried. Secondly, NaBH₄(M_NaBH4 /M_Compound2=6:1)was added slowly, and refluxed for 25h at 60℃, dilute HCl and methanol/H₂O（volume ratio,1:1） were used to rinse and filter the yields respectively after fully reacted. And thirdly, refluxed in 90% formic acid for 4h at 70℃, and evaporate to dryness, then CH₂Cl₂ was taken to extract, and isolated by chromatographic column on silica gel （CH₂Cl₂/acetone=10:1）. （3） 4.41（d, 6H, CH_a）, 3.41（d, 6H, CH_e）, 36.78(C_a,e) and 4.65（d, 6H, CH_a）, 3.43（d, 6H, CH_e）, 36.13(C_a,e) observed in the NMR test proved respectively that Cryptophane A and Cryptophane E were successfully synthesized. The maximum fluorescence emission wavelengths were 440nm and 435nm. Cryptophane A and E. In CH₂Cl₂ solvent, UV absorption peaks wereλ₁=236nm,λ₂=284nm for Cryptophane A,λ₁=234nm,λ₂=286nm for Cryptophane E.（4） The sensing experiment for methane showed that the best incidence angle for the methane fiber sensor was 15°, the suitable sensitive length are 3mm to Cryptophane A and 8mm to Cryptophane E. The adsorption and desorption time of the sensitive film to N₂/CH₄ when the velocity of the gas mixture was 100ml·min^-1 both 80s.更多还原