四聚乙醛

利用该催化剂在温度-10～-15℃下，反应8h，由乙醛合成四聚乙醛的收率为14.81%，含量为98.7%。

Under the temperature between - 10 ℃ and - 15 ℃ for 8 hours metaldehyde was obtained by polymerizing with acetaldehyde in the presence of compound hydrochloric acid catalyst . The purity of the product was 98.7 % and yield was 14.81 % .

在推荐使用剂量下，四聚乙醛在干烟叶中的残留量低于最低检出浓度0.10mg/kg，不会对烟草造成残留污染。

2 ) When metaldehyde was used as the recommended dosage , the residues of metaldehyde was below ( 0.10 mg / kg ) in dry tobacco , thus no any contamination to tobacco product .

由盐酸、盐酸羟胺、溴化钠、吡啶制得盐酸复合催化剂.使用盐酸复合催化剂合成四聚乙醛，替代了使用单一盐酸催化剂的传统合成方法。

The traditional way of synthesizing metaldehyde from single hydrochloric acid catalyst was replaced by a compound hydrochloric acid catalyst , which was prepared through hydrochloric acid , hydroxylamine hydrochloride , sodium bromide , pyridine .