建立在常温、常压条件下准确定量测定溶解乙炔含量的紫外-可见分光光度法,并对乙炔在丙酮、三乙二醇、N,N-二甲基甲酰胺和二甲基亚砜中的溶解特性进行系统考察;采用循环伏安法研究助溶剂丙酮、三乙二醇、N,N-二甲基甲酰胺和二甲基亚砜对乙炔电化学氧化过程的影响以及绿色溶剂TEG对该过程影响的作用机制。实验结果表明在常温、常压条件下,溶解乙炔的含量可采用紫外-可见分光光度法通过紫红色的乙炔铜进行准确测定,N,N-二甲基甲酰胺溶解乙炔的能力最强;在乙炔电化学氧化过程中,水分子和三乙二醇之间强烈的氢键作用是提高乙炔在Na_2SO_4溶液中溶解度的决定性因素;在含体积分数为9%TEG的0.5mol·L~(-1) Na_2SO_4溶液中,乙炔电化学氧化过程的表观活化能为13.20kJ·mol~(-1),属于受吸附控制的不可逆过程。该研究以期寻找一种乙炔的良好溶剂,为乙炔电化学氧化过程的研究、乙炔传感器(尤其是乙炔的电化学传感器)、绿色化学以及乙炔化工等的发展提供理论依据和实验指导。
A new view to determine concentration of dissolved acetylene in ambient temperature and pressure was put forward,and solubility of acetylene in different solvents was investigated by UV-Vis.(UV-Vis spectrophotometry).Influence of cosolvents such as acetone,TEG(triethylene glycol),DMSO(dimethyl sulfoxide),DMF(N,N-dimethyl formamide)especially the green cosolvent of TEG and its mechanism and volume fraction,temperature and scan rate on the process of electrochemical oxidation of acetylene at Pt electrode were examined by CV(cyclic voltammetry).The analysis results show that the concentration of dissolved acetylene can be determined accurately through claret-colored copper acetylide by UV-Vis.(at 542 nm),the solubility order of acetylene in different solvents is DMF〉DMSO〉TEG〉acetone,the hydrogen bonding interactions were identified as the main interaction controlling the mutual solubility of the H2O in Na2SO4 solution and TEG in the system,and when the supporting electrolyte is 0.5 mol·L-1 Na2SO4 with TEG(vol.9%),the dissolved acetylene can be the most easily oxidized by OH· from the electrolysis process of Na2SO4 solution and the ipa(anodic peak current)is maximum,the process of electrochemical oxidation of acetylene at Pd electrode is under adsorption control and irreversible,the Ea(apparent activation energy)of the process of electrochemical oxidation of acetylene at Pd electrode is 13.20 kJ·mol-1.This study expects to seek a kind of good solvent acetylene and provides theoretical basis and experimental guidance to the research of electrochemical oxidation acetylene process and the development of sensor for acetylene(especially electrochemical sensor for acetylene),green chemistry and acetylene chemical industry.