化工学报
化工學報
화공학보
JOURNAL OF CHEMICAL INDUSY AND ENGINEERING (CHINA)
2014年
6期
2193-2201
,共9页
王明%徐颖华%丁旭芬%马淳安
王明%徐穎華%丁旭芬%馬淳安
왕명%서영화%정욱분%마순안
准毛细间隙反应器%茴香醚%茴香醛二甲基缩醛%电化学%氧化%电解质%工艺条件
準毛細間隙反應器%茴香醚%茴香醛二甲基縮醛%電化學%氧化%電解質%工藝條件
준모세간극반응기%회향미%회향철이갑기축철%전화학%양화%전해질%공예조건
quasi capillary gap cell%p-methoxytoluene%anisaldehyde dimethyl acetal%electrochemistry%oxidation%electrolytes%process condition
以准毛细间隙反应器为电化学合成装置,采用恒电流电解技术考察了阳极材料、支持电解质、电流密度等工艺参数对茴香醚直接电氧化合成茴香醛二甲基缩醛的影响。结果表明,收率从高到低采用的阳极材料依次为:石墨>钛基铱钽>钛基钌铱>钛基铂;支持电解质依次为:对甲基苯磺酸钠>苯磺酸钠>氟化钾>甲醇钠>高氯酸钠>间硝基苯磺酸钠;在电流密度1~9 A·dm-2范围内,反应选择性随着电流密度的增大而减小;添加适量的2,6-二甲基吡啶能抑制茴香醛二甲基缩醛的氧化从而提高反应选择性。在优化条件下,茴香醛二甲基缩醛的收率和电流效率分别达到75%和47%。
以準毛細間隙反應器為電化學閤成裝置,採用恆電流電解技術攷察瞭暘極材料、支持電解質、電流密度等工藝參數對茴香醚直接電氧化閤成茴香醛二甲基縮醛的影響。結果錶明,收率從高到低採用的暘極材料依次為:石墨>鈦基銥鐽>鈦基釕銥>鈦基鉑;支持電解質依次為:對甲基苯磺痠鈉>苯磺痠鈉>氟化鉀>甲醇鈉>高氯痠鈉>間硝基苯磺痠鈉;在電流密度1~9 A·dm-2範圍內,反應選擇性隨著電流密度的增大而減小;添加適量的2,6-二甲基吡啶能抑製茴香醛二甲基縮醛的氧化從而提高反應選擇性。在優化條件下,茴香醛二甲基縮醛的收率和電流效率分彆達到75%和47%。
이준모세간극반응기위전화학합성장치,채용항전류전해기술고찰료양겁재료、지지전해질、전류밀도등공예삼수대회향미직접전양화합성회향철이갑기축철적영향。결과표명,수솔종고도저채용적양겁재료의차위:석묵>태기의단>태기조의>태기박;지지전해질의차위:대갑기분광산납>분광산납>불화갑>갑순납>고록산납>간초기분광산납;재전류밀도1~9 A·dm-2범위내,반응선택성수착전류밀도적증대이감소;첨가괄량적2,6-이갑기필정능억제회향철이갑기축철적양화종이제고반응선택성。재우화조건하,회향철이갑기축철적수솔화전류효솔분별체도75%화47%。
The influences of anodic electrode material,supporting electrolyte and current density on the direct electrochemical oxidation synthesis of anisaldehyde dimethyl acetal (p-MBDMA) in a quasi capillary gap cell were investigated by the galvanostatic method. The electrochemical behavior of p-methoxytoluene (p-MT) and p-MBDMA in methanol was studied with linear sweep voltammetry. The experimental results showed that graphite as anodic material revealed good electrochemical catalytic activity to the oxidation of p-MT. The p-MBDMA yield of four anodic materials decreased in the following order:graphite>Ir-Ta/Ti>Ru-Ir/Ti>Pt/Ti and six supporting electrolytes followed the decreasing order:sodium p-toluenesulfonate > sodium benzenesulfonate > potassium fluoride > sodium methoxide > sodium perchlorate > sodium 3-nitrobenzenesulfonate. With current density varying from 1 to 9 A·dm-2,reaction selectivity decreased with increasing current density. Furthermore,a proper amount of addition of 2,6-lutidine could improve the selectivity by avoiding further oxidation of p-MBDMA. Under the optimized conditions of 0.8~1.0 mol·L-1 p-MT,1.0%(mass) sodium p-toluenesulfonate as supporting electrolyte and addition of 0.5%(mass) 2,6-lutidine,yield and current efficiency could reach 75% and 47% respectively. During the process of electrolysis,current density changed from 3.0 to 2.0 A·dm-2 at 0.8 Q*and the operating condition was under the electrolyte solution flow rate of 20 L · h-1 at temperature 40℃. The research provided an important basis for commercialization of electrochemical oxidation synthesis of p-MBDMA.