The synthesis of aromatic dinitroderivatives of chloral effectively used in production of soluble, heat and fire resistant polyester and polyhetero arylenes using in the reaction of aromatic nucleophilic replacement was studied. The groups of new aromatic dinitroderivatives containing chloral as central groups between the phenyl nuclei: dichlorethelyne, carbonyl, acetylene and methylene groups were considered. The synthesis conditions were improved for polyester polyesterketones, polyesteretherketones, poliftalimides and polynaphtalamids without substantially affecting the thermal and solid characteristics achieved under relatively mild conditions using nucleophilic polynitro substitution. The search of new functional groups used in the condensation reactions, is an urgent task of polymer chemistry. Such groups must be determined by enough high reactivity of the monomers, without reducing their availability and without increasing their toxicity. It has decisive importance in the structure of initial monomers, which would be determined by the properties of polymers and the solubility of the target. In this aspect, dinitro compounds containing diphenyl, phthalimide and naftalimidnye cycles are presented their unique structures. It is known that improvement in meltability and solubility of the polymers without significant effect on the thermal and strength properties achieved by the introduction of these "carded" groups bulky substituents or phenyl phenoxide, flexible "bridge" fragments and introduced into the aromatic nuclei of the starting compounds bulk chlorine atoms. As part of this review it was made an attempt to describe methods of synthesis and properties of aromatic dinitropro- derivatives containing combinations of bulky substituents and flexible "bridged" groups using as initial compounds the simplest derivatives of chloral. The mostly known polyimides and polyetherimides prepared by reacting dianhydrides of aromatic tetracarboxylic acids with aromatic diamines with two-staged process where the first stage, a poly (o-carboxy) imides, and the second, due to thermal or catalytic imidization of polyamides with low solubility in organic solvents. It should be noted that the second stage -thermal or catalytic imidization not always results in a totally cycling polyamides that reduces the possibility of a relatively high molecular weight of polymers. At using aromatic dinitro- compounds containing a phthalimide and naftalimide cycles as comonomers bis-phenols, the problem of the extent of cyclization is absent. It was noted that an important determinant of obtaining high molecular weight of polymers is using nucleophilic polinitro-substitution in a process flow on the first stage under relatively mild conditions in a medium of DMSO or DMSO / toluene at 70 °C for 2 h in a completely dry environment. The review deals with some aspects of activation mechanism of nitro groups in nucleophilic polynitro-substitution. The processes of synthesis of condensation monomers of dinitro-derivatives using chloral were considered in detail. The methods of preparation and some properties of aromatic dinitroarilene, dinitroftalimide and dinitronaftalimide with dichlorethylenes, ketones, acetylene and methylene "bridged" groups between the phenyl nuclei are given. Forcitation:Kumykov R.M., Vologirov A.K. New aromatic dinitroderivatives of chloral as monomer for synthesys of polyester and polyhetero- arylene. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 2. P. 4-14
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Sep 1, 2021
A S Komolov + 6
Open Access