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A procedure was developed for preparing a plasticizer for polyvinyl chloride compounds from the fraction of dioxane alcohols. The main physicochemical properties of the new plasticizer were determined. Items prepared from formulations containing the new plasticizer were fabricated and tested in laboratory.Since the discovery of the dioxane method for preparing isoprene, the utilization or reprocessing of dioxane alcohols has been topical problem.The world's annual production of isoprene reaches now 1000 31100 thousand tons, of which 250 thousand tons (23325% of the total amount) is produced by the dioxane method. In Russia, the annual production of isoprene is 700 3800 thousand tons, of which 190 thousand tons (24 327% of the total amount) is produced by the dioxane method. In this method, the amount of dioxane alcohols (by-products) reaches 100 3110 kg per ton of isoprene. Thus, formation of large amounts of dioxane alcohols is inevitable [1].The fraction of dioxane alcohols from the production of isoprene rubber is a colorless or light yellow mobile liquid containing 50 370 wt % dioxane alcohols; the boiling onset temperature is no less than 225oC, and the flash point, no less than 120oC. The fraction belongs to hazard class 3, recommended value of MPC (with respect to dioxane alcohol) 10 mg m !3 , LD 50 for mice 2700 mg kg !1 [2]. The fraction of dioxane alcohols contains three isomeric alcohols: C HOCH 2 CH 2 O Ä CH 2 CH 3 i ei O Ä CH 2 ÄCH 2 e ie 4-Methyl-4-hydroxyethyl-1,3-dioxane (I) C O Ä CH 2 i ei O Ä CHÄCH 2 e ie CH 3 CH 3 g g CH 2 OH 4,4-Dimethyl-5-hydroxymethyl-1,3-dioxane (II) CH 3 ÄCÄCH e CH 2 ÄO i g g g g CH 3 OH i e CH 2 CH 2 ÄO ethyl)-1,3-dioxane (III) 5-(1-Methyl-1-hydroxy-The major component (60 370% of the sum of the isomers) is 4-methyl-4-(2-hydroxyethyl)-1,3-dioxane I.A number of possible applications of dioxane alcohols have been outlined in the literature: as an efficient solvent for nitrocellulose, nitrocellulose lacquers, rosin, lac, for bakelite, epoxy, and polyvinyl chloride resins, and for insulating lacquer; as a component of epoxy hardener [3 3 8]. One of promising ways of processing of the fraction of dioxane alcohols is preparation of plasticizers for polyvinyl chloride resins and rubbers [9 313].However, proper utilization of this large-tonnage waste remains a matter of current interest.We believe that the presence of hydroxy and acetal groups in molecules of dioxane alcohols, their low toxicity, absence of odor and color, and high boiling and flash points make these compounds interesting both as objects for theoretical studies (reactivity) and as potential raw materials for chemical industry.Our goal was to examine the possibility of preparing esters from dioxane alcohols and carboxylic acids, as potential plasticizers.

Objectives.The intensification of modern large-tonnage Russian technologies requires a deep investigation into the theoretical foundations of these processes and searching for ways that would significantly reduce the time and cost of their development, as well as to ensure the access of high-quality products on the world market. The aim of the work was to study the options regarding technological changes in the process of obtaining cyclohexanone at two stages: 1) oxidate (cyclohexane oxidation product after the stage of neutralization and removal of the main amount of unreacted cyclohexane) saponification and 2) end product rectification. The changes should ensure the high quality of the product without requiring significant energy and investment costs.Methods.Studies of heterophase alkaline hydrolysis with NaOH solutions were carried out at 30–80 °C in the presence of and without a phase transfer catalyst (PTC) (saponification conditions in the industry are 70 °C). The homophase process was studied in the presence of KOH at 120 °C (industrial conditions for raw cyclohexanone rectification are 90–130 °C) on artificial mixtures based on industrial samples of the oxidate with the addition of model substances (oxygencontaining impurities with a main substance content of no less than 95%). Analysis of the initial and obtained products was carried out using gas-liquid chromatography and chromatographymass spectrometry.Results.The totality of the obtained data provides theoretical justification for the fact: 50– 70% of esters and unsaponifiable impurities can be removed by using heterophase alkaline saponification in industrial environments. The post-treatment of crude cyclohexanone by rectification in the presence of KOH decreases the ester number by a factor of 3–5, however, the number of cyclohexanone condensation products in the bottom sharply increases. The amount of these substances varies from 10 to 20 kg/t of cyclohexanone depending on compliance with the conditions. In the presence of PTC, the conversion of esters at the saponification stage is 95–100%, aldehydes 100%, and unsaturated ketones 80%.Conclusions.If the proposed technology for saponification in the presence of PTC is adopted there will be no need to use an alkali during the process of cyclohexanone rectification. This makes the process more stable, reduces the losses of cyclohexanone, reduces the amount of tars, and normalized indicators of cyclohexanone quality are attained.

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