Applications of Cryptand/ Piezoelectric Crystal Membranes and Crown Ethers in Detection of Olefin Vapours and Catalyzed Organic Substitution

• Main Authors: Sheng, Horng-Jeng, 謝宏政
• Other Authors: Shih, Jeng-Shong
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/17099719661368733600

碩士 === 國立臺灣師範大學 === 化學學系 === 82 === 　　Macrocyclic polyethers, e. g. cryptands and crown ethers were synthesized and applied as coating materials on quartz piezoelectric crystal membranes for detection of olefin vapours and as phase transfer catalysts for substitution of aromatic halides ( ArX) with hexyne in base (NaNH2) organic solutions. 　　Piezoelectric crystal membranes sensors based on cryptand -22/Ag+/PVC/en/NH2 for olefin vapours e. g. alkene and alkyne were developed in this study. The cryptand gas sensor exhibited a high sensitivity with a frequency shift about 80Hz/(mg/L) for 1-heptene short response time with <4.0 min and good reproducibility for reusage. The cryptand 22/Ag+showed as a sensitive coating for olefin vapours but not for saturated organic vapours such as alcohols and amines. Steric effect and isomer effect on frequency shifts of the cryptand /Ag+ sensor were abso investigated. Alkenes with higher carbon number showed better sensetive than smaller alkenes and cis-type alkenes gave better response than trans-type alkenes. 　　Various crown ethers, e. g monobenzo-15-crown-5 (B15C5), dibenzo 18 crown 6 (DB18C6), 15-crown-5 (15C5) and 12-crown-4 (12C4) were synthesized and applied as phase transfer catalysts for substition of aromatic halides with hexyne. Among crown ethers B15C5 exhibited the best catalyst and can catalyze the substitution with the yields from 0.3% ( blank without crown ether ) to 60% (with crown ether ) in 4 hr at 75℃. . The catalytic abilities of these crown ethers exhibited in the order B15C5>15C5>DB18C6>12C4. The catalyzed subistitution showed higher yieds in lower polar solvents such as benzene and toluene and higher reaction temperature. In addition effects of concentiations of crown ethers and reactants, type and concentration of base were investigated and discussed.