Study on Visibility level for Road Lighting

Uozumi, Takuji; Ueno, Tomoko; Kawakami, Kohji

doi:10.2150/jieij1980.85.appendix_161

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“…This is an equilibrium reaction in which the generation of the monoester is favored. Monoesterification of different aliphatic alcohols with phthalic anhydride, − maleic anhydride, or hexahydrophthalic anhydride is observed to be reasonably fast without any catalyst. Specific examples for benzyl alcohol are also observed. , The formed monoester, i.e., the modified alcohol, has one carboxylic group available that can dissociate in the presence of a basic salt, producing a charged and therefore more water-soluble carboxylate (Scheme b).…”

Section: Reactive Extraction Of Modified Alcoholmentioning

confidence: 98%

Reactive Extraction of Alcohols from Apolar Hydrocarbons with Aqueous Solutions

Kuzmanovic

Kuipers

Haan

et al. 2004

Ind. Eng. Chem. Res.

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Use of aqueous solutions as reactive extraction solvents for the recovery of monohydroxyl alcohols present in few-percent concentrations in apolar hydrocarbons is evaluated. Two approaches are considered. The first, in which an aqueous solution containing a reactive extractant is applied for the recovery of the alcohol, shows only limited potential to be used. Among several potential extractants, only hydroxypropyl cyclodextrins and silver nitrate were able to achieve a slight improvement of the distribution ratio of benzyl alcohol relative to pure water. In addition to providing moderate values of the distribution ratios of benzyl alcohol, these extractants are also found to increase the solubility of the apolar organic solvent in the aqueous phase and thereby cause a decrease in selectivity toward the alcohol. The second considered approach, in which the alcohol is chemically modified prior to the extraction into an easily extractable form, in this case a monoester, has much more potential. A benign solvent, such as an aqueous solution of sodium hydrogen carbonate, can provide a distribution ratio of benzyl alcohol of up to 200, leaving the solubility of the organic solvent in the aqueous solutions unchanged relative to that in pure water. The modification of aromatic, cycloaliphatic, and linear aliphatic alcohols can be done efficiently in an apolar organic solvent without need for a catalyst. It is found that the back-recovery of alcohol extracted in this way can be performed by back-extraction after the monoester has been hydrolyzed. The rate of hydrolysis can be controlled by temperature. Hence, an efficient and selective recovery of alcohols can be achieved by reactive extraction using aqueous solutions of a hydrogen carbonate salt by modifying the alcohol into a monoester prior to the extraction.

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