Study On The Synthesis And Crystallization Process Of 1,4-diazabicyclo(2.2.2)octane

1,4-diazabicyclo(2.2.2)octane exhibits certain unusual tertiary amine properties which are due to its bicyclic or"cage"structure. It is an important intermediate and end product in the chemical industry, which is used mainly as a catalyst in the production of polyurethane foams. The preparation of 1,4-diazabicyclo(2.2.2)octane by reaction of ethylenediamine or monoethanolaimine in the presence of catalyst were studied to get the right catalyst, which have good yield and selectivity and long catalyst life. 1,4-diazabicyclo(2.2.2)octane are easy to agglomeration. To get the good particle size of the 1,4-diazabicyclo(2.2.2)octane products which could decrease the agglomeration rate and extend the storage time, the crystallization process was studied in the manuscript.The zeolite of the MFI type is used, because of right pore diameters. In a particular embodiment, the zeolites (HZSM-5 or HTS-1) were doped by applying alkali, alkaline earth or transition metals of subgroups (such as Cu or Ni compounds) IA, IIA and IVB to VIII and a series of catalysts were get. The catalysts were characterized. The catalytic activities of catalysts were studied in the fixed-bed catalytic reactor. The right catalyst of each reaction was gain. The influences of various reaction parameters were discussed respectively.Ionic liquids have been widely utilized in the area of organic chemistry as novel solvents or catalysts. It is an object of the present invention to find an economical process for the preparation of 1,4-diazabicyclo(2.2.2)octane from readily accessible starting compounds which is improved compared with the prior art. Ionic liquids based on 1-n-butyl-3-methylimidazolium [Bmim] and 1-n-butyl-pyridine [BPy] with different anions such as Br^-, BF₄^- and PF₆^- were synthesized and chanractered. The influences of various parameters of the reactions were discussed. The ionic in the studies on conversion of ethylenediamine or Monoethanolamine over ionic liquids, 1,4-diazabicyclo(2.2.2)octane was obtained in good yield. The influences of various reaction parameters were discussed. The ionic liquids were possible to recycle and reuse.Crystallization threomdymics is the key factor in design and optimization of the crystallization process. In this thesis, the solubility and metastable zone of 1,4-diazabicyclo(2.2.2)octane in several pure solvents such as methanol, ethanol, isopropanol, n-butanol, acetone, acetic ester and n-hexane different temperatures were measured by laser monitoring method. The effects of cooling speed and mole fraction of methanol, ethanol and isopropanol on metastable zone were studied. The induction period and interfacial tension of ethanol was also measured. On the basis of thermodynamics study, the cooling crystallization process was optimized experimentally. To get the scoopable product of 1,4-diazabicyclo(2.2.2)octane, the effect of process parameters (such as cooling rate and concentration of original solution) on the product quality was studied in detail. As a result, the relative better crystallization process was brought forward. The basic data for further study and for industrial production was supplied.