乙二胺催化合成三乙烯二胺及热力学分析
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摘要
用Aspen Plus软件对乙二胺(EDA)合成三乙烯二胺(TEDA)体系中涉及到的主要化合物的热力学参数进行估算,并对涉及到的主、副反应的焓变、吉布斯自由能变和平衡常数随温度的变化进行了计算。以氯化钾为前驱体,用离子交换法改性HZSM-5制备KZSM-5催化剂,通过XRD,吡啶吸附红外光谱(Py-IR)表征,KZSM-5没有氯化钾晶体生成,骨架B酸位消失,L酸位变丰富。在温度340℃常压下,进料浓度5. 90 mol/L,停留时间88. 06 min下,原料转化率和三乙烯二胺的选择性分别为85%和51%。对催化机理进行分析,气相主体的乙二胺分子进入KZSM-5孔道,被K~+活化生成二乙烯三胺,经分子内环合生成哌嗪。哌嗪从分子筛孔道中脱附进入气相主体在瓷环层与乙二胺反应生成三乙烯二胺。
Thermodynamic analysis of ethylenediamine to triethylenediamine reaction system was carried out. By using the Aspen Plus software,unknown parameters of thermodynamics were estimated,the enthalpy changes,Gibbs free energy changes and equilibrium constant of each reaction were calculated in detail as a function of temperature. The catalysts were prepared through modifying HZSM-5 zeolite by KCl ion exchange method and the structure and acidity of the catalysts were investigated with XRD,Py-IRtechnologies. The results showed that the KZSM-5 had no crystal formation of potassium chloride,the B acid bit disappeared,the L acid bit became enriched. The catalytic performance of KZSM-5 in synthesis of triethylenediamine( TEDA) from ethylenediamine( EDA) were investigated. The conversion rate of raw materials( EDA) and the selectivity of TEDA are 85% and51% respectively,under the normal pressure,340 ℃,and the concentration of the raw material is 5. 90 mol/L,and the stay time is 88. 06 min. Catalytic mechanism explored,the gas phase of EDA molecule into KZSM-5 channel,combined with K+by activation and the other EDA molecules to form diethylenetriamine( DETA). The DETA was combined with K+to form PA in the elliptical channel,and the PA was removed from the molecular sieve pore to enter the main body of the gas phase to synthesize TEDA directly in the ceramic ring layer.
Thermodynamic analysis of ethylenediamine to triethylenediamine reaction system was carried out. By using the Aspen Plus software,unknown parameters of thermodynamics were estimated,the enthalpy changes,Gibbs free energy changes and equilibrium constant of each reaction were calculated in detail as a function of temperature. The catalysts were prepared through modifying HZSM-5 zeolite by KCl ion exchange method and the structure and acidity of the catalysts were investigated with XRD,Py-IRtechnologies. The results showed that the KZSM-5 had no crystal formation of potassium chloride,the B acid bit disappeared,the L acid bit became enriched. The catalytic performance of KZSM-5 in synthesis of triethylenediamine( TEDA) from ethylenediamine( EDA) were investigated. The conversion rate of raw materials( EDA) and the selectivity of TEDA are 85% and51% respectively,under the normal pressure,340 ℃,and the concentration of the raw material is 5. 90 mol/L,and the stay time is 88. 06 min. Catalytic mechanism explored,the gas phase of EDA molecule into KZSM-5 channel,combined with K+by activation and the other EDA molecules to form diethylenetriamine( DETA). The DETA was combined with K+to form PA in the elliptical channel,and the PA was removed from the molecular sieve pore to enter the main body of the gas phase to synthesize TEDA directly in the ceramic ring layer.
引文
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[12]ZIMMERMAN,ROYBORT Le Roy.Method for manufacture triethylenediamine:EP,0454395A1[P].1991-10-30.
[2]王志刚,翟封振,卫慧凯,等.三乙烯二胺合成工艺研究[J].精细化工,1994(6):57-60.
[3]尚会建,王力伟,李慧,等.钛硅分子筛催化乙醇胺合成三乙烯二胺工艺研究[J].现代化工,2014,27(2):110-114.
[4]尚会建,王少杰,王丽梅,等.乙醇胺合成三乙烯二胺工艺的研究[J].聚氨酯工业,2012,27(2):23-26.
[5]赵凌雁,郭洪臣,陈黎行,等.在MFI型高硅沸石上用一乙醇胺选择性合成三乙烯二胺[J].现代化工,2003,23(Z1):193-197.
[6]ANAND RAO,RAO B S.Conversion of piperazine over acidic zeolites[J].Catalysis Communications,2002,V3(10):479-486.
[7]陈立功,古险峰,许正双,等.哌嗪乙基衍生物合成三乙烯二胺[J].化学工业与工程,2001,18(1):34-39.
[8]白国义,陈立功,李阳,等.三乙烯二胺的合成研究[J].化学推进剂与高分子材料,2000,73(1):27-28.
[8]WEITKAMP J,ERNST S.Synthesis of piperazine and triethylenediamine using ZSM-5-type zeolite catalysts[J].Studies in Surface Science and Catalysis,1991,65(8):297-304.
[10]胡晓,王苏,王玉成.使用改性沸石催化剂合成三乙烯二胺[J].化工科技,2000,8(3):45-46.
[11]韦雄雄.合成无水哌嗪催化剂的研究[D].西安:西北大学,2012.
[12]ZIMMERMAN,ROYBORT Le Roy.Method for manufacture triethylenediamine:EP,0454395A1[P].1991-10-30.