- Identification of 1,3-dioxanes and 1,3-dioxolanes as malodorous compounds at trace levels in river water, groundwater, and tap water
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A study of organic compounds imparting odor problems in river waters and groundwaters has been conducted. The Tordera aquifer located in Barcelona and Girona (NE Spain) is the water supply reserve for many seasonally crowded villages on the coast. Closed loop stripping analysis (CLSA) and flavor profile analysis (FPA) have been employed as analytical tools to identify the compounds responsible for the odor complaints. The feasibility of purge-and- trap (P and T) has also been evaluated. The 2-alkyl-5,5-dimethyl-1,3-dioxanes and 2-alkyl-4-methyl-1,3-dioxolanes were the most significant compounds identified in river water and groundwater with a threshold odor of 10 ng/L for 2-ethyl-5,5-dimethyl-1,3-dioxane (2EDD), the most malodorous compound. The analyses were carried out by HRGC/MS, and the synthesized 1,3-dioxanes and dioxolanes were characterized by CI-MS and EI-MS/MS techniques. A company, currently manufacturing saturated and unsaturated polyester resins, located in the upper course of the river, produced these compounds as byproducts during the synthesis of resins. The pollution by dioxanes and dioxolanes affected all the aquifer and slowly diminished to the ppt levels when the company was forced to correctly treat their wastewaters. Additional examples of the presence of dioxanes and dioxolanes in wastewaters of other resin plants and also tap water of Barcelona are shown. A study of organic compounds imparting odor problems in river waters and groundwaters has been conducted. The Tordera aquifer located in Barcelona and Girona (NE Spain) is the water supply reserve for many seasonally crowded villages on the coast. Closed loop stripping analysis (CLSA) and flavor profile analysis (FPA) have been employed as analytical tools to identify the compounds responsible for the odor complaints. The feasibility of purge-and-trap (P&T) has also been evaluated. The 2-alkyl-5,5-dimethyl-1,3-dioxanes and 2-alkyl-4-methyl-1,3-dioxolanes were the most significant compounds identified in river water and groundwater with a threshold odor of 10 ng/L for 2-ethyl-5,5-dimethyl-1,3-dioxane (2EDD), the most malodorous compound. The analyses were carried out by HRGC/MS, and the synthesized 1,3-dioxanes and dioxolanes were characterized by CI-MS and EI-MS/MS techniques. A company, currently manufacturing saturated and unsaturated polyester resins, located in the upper course of the river, produced these compounds as byproducts during the synthesis of resins. The pollution by dioxanes and dioxolanes affected all the aquifer and slowly diminished to the ppt levels when the company was forced to correctly treat their wastewaters. Additional examples of the presence of dioxanes and dioxolanes in wastewaters of other resin plants and also tap water of Barcelona are shown.
- Romero, Jordi,Ventura, Francesc,Caixach, Josep,Rivera, Josep,Gode, Llui Xavier,Ninerola, Josep Ma.
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p. 206 - 216
(2007/10/03)
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- Reaction of 5,5-, 2,5,5-, and 2,2,5,5-Substituted 1,3-Dioxanes with an Ester of Isobutylboronic Acid
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GLC study showed that the reaction of substituted 1,3-dioxanes with diisobutyl isobutylboronate results in the corresponding 1,3,2-dioxaborinanes. The reactivity of the 1,3-dioxanes increases with increasing alkyl substitution in the 2 position, the nitro group at the C5 atom also markedly enhances the reactivity. With the example of the reaction of 2-isobutyl-5,5-dimethyl-1,3,2-dioxaborinane with acetaldehyde diethylacetal the reaction was shown to be reversible; however, the equilibrium is almost completely shifted to the cyclic ester of boric acid.
- Kuznetsov,Tereschenko,Gren'
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p. 263 - 265
(2007/10/03)
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- REACTION OF CYCLIC ACETALS WITH 1,3-DIOXANIUM SALTS
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The products from reaction of 1,3-dioxacycloalkanes with 1,3-dioxanium tetrafluoroborates are a new pair of compounds, i.e., 1,3-dioxacycloalkanium tetrafluoroborate and 1,3-dioxane.The reaction is reversible and takes place by a transacetalization mechanism.
- Chalova, O. B.,Kurmaeva, E. S.,Kantor, E. A.,Kiladze, T. K.,Rakhmankulov, D. L.
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p. 1434 - 1437
(2007/10/02)
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