The possibility of using unsaturated phthalates obtained by the esterification of phthalic anhydride with distillation residues of butyl alcohols as a basis for the synthesis of a bromine-containing plasticizer-fire retardant was evaluated. prene, polyvinyl chloride, and polyvinyl acetate. Instability of the content of unsaturated esters of phthalic acid in the test object was noted with the most probable range of fluctuations in iodine number, ranging from 24.4 to 44.4. A direct dependence of the indicated variation limits on the content of 2-ethylhexene-3-ol-1 in the distillation residue of butanol in the amount of 9.0-17.5% and 2-ethylhexen-2-ol in the amount of 35-43% was established. The ratio of unsaturated esters of 2-ethylhexyl-2-ethylhexene-3-phthalate and 2-ethylhexyl-2-ethylhexene-2-phthalate in an unsaturated plasticizer is 1: 2 ÷ 5. It has been shown that with a shortage in production of a brominated plasticizer with a low bromine content, its required amount can be obtained by diluting a brominated plasticizer with a high bromine content. Dioctyl phthalate and the investigated unsaturated plasticizer were proposed as diluents. It is noted that with incomplete bromination of an unsaturated base, unsaturated esters do not adversely affect the quality of the compositions, make the bromine-containing system more reactive, which leads to additional crosslinking of polymer molecules and an increase in the strength of the composition. It is shown that the modification of an unsaturated plasticizer by bromination will make it possible to obtain a triple effect of inhibition of the combustion process due to the elimination of hydrogen bromide from brominated ethers, an increase in the duration of its elimination and the ability of unsaturated ethers to react with active radicals released during thermal decomposition and combustion of polymer compositions.
The main characteristics of a complex system of unsaturated plasticizer-bromine using the main "working components" - isomers of 2-ethylhexyl-2-ethylhexene phthalate are considered. It is taken into account that the phthalate-type ester plasticizer is a polar compound with a dipole moment at the level of dioctyl phthalate included in its composition. It has been shown that in the process of bromination, molecular bromine enters into physical interaction with all components of the plasticizer. Dosed introduction of bromine into the system at high stirring speeds leads to the formation of a homogeneous thermodynamically stable system, since the solubility parameters of the components are practically the same. Using a model mixture of bromine-dioctyl phthalate-dibutyl phthalate, it was shown that mixing bromine with plasticizers in any investigated ratios does not lead to the appearance of the boundary “bromine in a plasticizer” or “plasticizer in bromine”. This established the unlimited solubility of bromine in the plasticizer under the conditions of its bromination. Using the method of UV spectroscopy on model mixtures of acetic acid-bromine-water; acetic acid-bromine-hexane, it was proved that in a real system, unsaturated plasticizer-bromine, bromination is most likely carried out only with molecular bromine without the formation of bromine dimers. The mechanism of bromination of unsaturated phthalates included in the plasticizer is shown. A system of kinetic equations in dimensionless variables is proposed. It was found that the nature of the theoretical curves significantly depends on the rate of introduction of bromine with a constant reaction mechanism. A change in the limiting stages of the bromination process was noted depending on the rate of bromine introduction into the system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.