| 摘要 |
In an example, diethyl dodecafluorosuberate was prepared by esterifying dodecafluorosuberic acid with ethanol in the presence of sulphuric acid. An ethanol/water solution of the ester was then reacted with hydrazine to give dodecafluorosuberodihydrazide which was recrystallised from ethanol. Other perfluoroacyldihydrazides are obtainable similarly.ALSO:Fluorine containing polyhydrazides have a repeating unit of formula: <FORM:0960140/C3/1> where Rf is a perfluoroalkylene radical of at least 3 carbon atoms and Ar is a bivalent aromatic hydrocarbon radical of 6 to 18 carbon atoms which may be substituted by alkyl, alkoxyl or halogen radicals. The polymers may be prepared by reacting a perfluoroacyldihydrazide, H2N-NH.CO.Rf.CO.NH.NH2, with an equimolecular proportion of an aromatic dialdehyde, OHC.Ar.CHO, where Rf and Ar are as defined above, with the elimination of water. Many suitable perfluorodihydrazides and aromatic dialdehydes are specified. In the examples polymers are prepared from dodecafluorosuberodihydrazide and terephthalaldehyde or isophthalaldehyde. The thermally stable, fusible products based on isophthalaldehyde may be used as heat transfer media. The thermally stable, infusible terephthalaldehyde based products may be used to increase the viscosity of the fusible polymers. |
