Ecologically friendly and catalytic process "Research and Development of catalysts for selective synthesis of ethylenediamine"

研究了在酸性沸石催化剂上乙醇胺与氨合成乙二胺的反应。在所研究的沸石中，H-EDTA-莫尔（H_4EDTA脱铝的H型丝光沸石）是最好的催化剂。该反应证明对EDA的选择性高于H-EDTA-莫尔，副产物为少量的乙烯亚胺和哌嗪衍生物。随着NH_3分压的增加，催化剂的活性提高。反应的初始产物是E1，随后形成EDA。结果表明，EDA的形成需要在丝光沸石孔道中具有较强的酸性位，并具有过量的NH_3。丝光沸石通道可以延迟较大的哌嗪衍生物和其它多胺的形成。EA与H-EDTA-莫尔的反应是通过加入H-EDTA-MOR的质子使其与氨离子反应，然后EA的氨离子在催化剂的活性位上发生分子内缩合反应生成E1中间体。本文用红外光谱法研究了H_4EDTA和不同浓度的盐酸对脱铝丝光沸石的影响（吡啶吸附），XRD，XRF，用MAS NMR对催化剂进行了表征，并对催化剂的催化活性和产物进行了GO-MS分析（由IR光谱计算）随着脱铝的进行而增加。在Si/Al（bulk）=5左右达到最大值，然后下降。催化活性随吡啶用量的增加而增加，随结晶度和吡啶用量的减少而降低。即催化反应曲线与酸的用量密切相关，尤其是布朗斯台德酸。对脱铝过程中酸量增加的原因进行了探讨。

The synthesis of EDA (ethylenediamine) from EA (ehtanolamine) with NH_3 over acidic types of zeofite catalyst was investigated. Among the zeolites tested in this study, H-EDTA-MOR (H-type mordenite dealuminated with H_4EDTA) was the best catalyst. The reaction proved to be highly selective for EDA over H-EDTA-MOR, with small amounts of ethyleneimine and piperazine derivatives as the side products. The catalytic activity for EDA synthesis rises with increasing partial pressure of NH_3. The initial product of reaction was El, and the formation of EDA followed. The results suggest that the formation of EDA required stronger acidic sites in the mordenite channels with excess amounts of NH_3. The mordenite channels may retard the formation of bulkier piperazine derivatives and other polyamines. The reactions of EA proceed through ammonio-ions by the addition of protons of H-EDTA-MOR ; then intramolecular condensation of ammonioions of EA occurred to produce an El intermediate over the active sites of the catalyst. ethyleneimine is protonated by the stronger acidic sites with excess amounts of NH_3 to produce EDA.Dealuminated mordenites by H_4EDTA and hydrochloric acid of different concentration were investigated with IR (pyridine adsorption), XRD, XRF, MAS NMR.Each catalyst was used to test the catalytic activity and the produsts were analyzed with GO-MS.The amount of adsorbed pyridine (calculated from IR spectra) increased as the dealumination proceeds. It reached its maximum around Si/Al (bulk) =5, and then decreased. The catalytic activity increased as the amount of pyridine increased, and it decreased as the crystallinity and the pyridine amount decreased. That is, the curve of catalytic reaction strongly relates to the acid amount, especially Bronsted acid. It is under investigation the reason the acid amount increased with dealumination.