mechanism for the formation of 1,4-dioxane
In one study, 1,4-dioxane was not removed from effluent treated using ozone and activated carbon  , and thus, additional treatments are required, such as advanced oxidation processes (AOPs) [11,12] .
O O 14 dioxane Page 6 of 9 4 16 points The following ..
In summary, we developed a concise and highly enantioselective synthesis of colchicine (>99% ) in eight steps in 9.3% overall yield without the need for protecting groups. An unusual Wacker oxidation was used for enabling the regioselective construction of the highly oxidized tropolone C-ring. β-Lumicolchicine was prepared through a 4π-electrocyclization reaction with a much-improved yield compared with existing procedures, and the allocolchicinoid NCME was synthesized from β-lumicolchicine through a novel decarbonylation/electrocyclic ring-opening cascade reaction.
AB - Three novel partially fluorinated monomers, bis(2,2-difluorovinyl)formal (I), bis(2,2-difluorovinyl)difluoroformal (II), and bis(1-deuterio-2,2-difluorovinyl)difluoroformal (III), were prepared. These monomers were polymerized in bulk via free radical mechanism. Monomer I produced a cross-linked polymer, but monomers II and III yielded amorphous polymers (II-P and III-P) having five- and six-membered rings along the backbone. Polymers II-P and III-P were soluble not only in fluorinated solvents but also in nonfluorinated solvents such as THF, 1, 4-dioxane, DMF, and DMSO. They have good thermal stability (onset of decomposition >400°C), high glass transition temperatures (105°C), and low dielectric constant (1.98-1.82 at frequency ranging from 0.1 to 3 × 10 6 Hz). Furthermore, these polymers are completely amorphous and possess outstanding optical clarity extending from visible to near-IR regions. The refractive indices of both polymers were measured at various wavelengths to evaluate material dispersion. The material dispersions of II-P and III-P were similar and had low values, which are comparable to perfluorinated polymers and much lower than perdeuterioPMMA. The unique optical properties of these polymers make them attractive for use as optical materials.
acetonitrile, dimethylformamide, or 1,4-dioxane ..
1,4-Dioxane is an EPA priority pollutant often found in contaminated groundwaters and industrial effluents. The common techniques used for water purification are not applicable to 1,4-dioxane, and the currently used method (distillation) is laborious and expensive. This study aims to understand the degradation mechanism of 1,4-dioxane and its byproducts in dilute aqueous solution toward complete mineralization, by using the UV/H2O2 process in a UV semibatch reactor. The decay of 1,4-dioxane generated several intermediates identified and quantified as aldehydes (formaldehyde, acetaldehyde, and glyoxal), organic acids (formic, methoxyacetic, acetic, glycolic, glyoxylic, and oxalic) and the mono- and diformate esters of 1,2-ethanediol. Measurement of the total organic carbon (TOC) during the treatment indicated a good agreement between the experimentally determined TOC values and those calculated from the quantified reaction intermediates, ending in complete mineralization. A reaction mechanism, which accounts for the observed intermediate products and their time profiles during the treatment, is proposed. Considering the efficacy of the 1,4-dioxane removal from dilute aqueous solutions, as shown in this work, the present study can be regarded as a model for industrially affordable Advanced Oxidation Technologies.
Asymmetric synthesis using 4,4,6-trimethyl-1,3-dioxanes
A concise and highly enantioselective synthesis of colchicine (>99% ) in eight steps and 9.3% overall yield, without the need for protecting groups, was developed. A unique Wacker oxidation was used for enabling regioselective construction of the highly oxidized and synthetic challenging tropolone C-ring. Furthermore, asymmetric syntheses of β-lumicolchicine and -acetylcolchinol--methyl ether (NCME) were achieved. Notably, NCME was synthesized from β-lumicolchicine by an unusual decarbonylation and electrocyclic ring-opening cascade reaction.
that 4,4,6-trimethyl-1,3- dioxanes have little ..
The World Health Organization guideline for 1,4-dioxane is 50 μg/L in potable water  .Several methods have been employed to remove 1,4-dioxane from water, but it appeared to be difficult to remove by carbon adsorption or by air stripping due to its hydrophilic character [6–9] .