Production of lactic acid esters by reactive distillation

Yalçın, Özgen
The esterification of lactic acid with ethanol over Lewatit S 100, strong cation ion exchange resin catalyst, was studied in counter current vapor-liquid contactor type differential reactor by feeding ethanol and lactic acid solution as vapor and liquid phases, respectively. The ethanol vapor phase was diluted by dry air and the water removal was achieved by the mass transfer of water from liquid to vapor phase. Effect of ethanol to lactic acid feed molar ratio and vapor flow rate on fractional conversion and water removal efficiency were tested at 40-70°C of column temperature range. It was observed that Lewatit S 100 was adequate catalyst for esterification of lactic acid with ethanol. Increase in ethanol to lactic acid feed molar ratio enhanced both lactic acid conversion and water removal by upper product stream. However, lactic acid conversion was suppressed by the increase of inlet vapor flow rate because of the decrease in ethanol concentration in gas phase which affected both esterification reaction rate and mass transfer rate. The reaction temperature is the other important parameter that affects the mass transfer of ethanol from vapor to liquid phase. Although reaction rate and equilibrium conversion values were promoted by temperature, the lower solubility of ethanol in liquid phase limited the fractional conversion while promoted the water mass transfer from liquid to vapor phase. The optimized vapor phase velocity and temperature can yield higher conversions than the equilibrium conversion at the same temperature and initial composition. Therefore, low pressure organic acids such as lactic acid can be successfully esterified by using counter current V-L contactor type reactors and by using integrated reaction and separation units.


Production of lactic acid esters catalyzed by heteropoly acid supported over ion-exchange resins
AYTURK, E; Hamamcı, Haluk; Karakaş, Gürkan (2003-01-01)
The heterogeneous liquid-phase esterification reaction of lactic acid with ethyl alcohol accompanied with lactoyllactic acid hydrolysis over heteropoly acid supported on ion exchange resin catalysts was investigated at 343 K with ethanol to lactic acid molar ratio of 1:1. The catalysts with 5-20% of tungstophosphoric (H(3)PW(12)O(40).xH(2)O) and molybdophosphoric (H(3)PMo(12)O(40).xH(2)O) acid type of heteropoly acids over Lewatit(R) S100 showed higher activities than the resin itself. DRIFTS and XRD analys...
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Ersöz, Tuğçe İrfan; Karakaş, Gürkan; Department of Chemical Engineering (2009)
Semiconductor metal oxides can be induced by light with proper wavelength resulting in oxidation and reduction reactions for the transformation of water and oxygen molecules into active radicals. With this method, it is possible to obtain self-cleaning surfaces and products having antimicrobial properties. The aim of this study is to develop semiconductor metal oxide thin films for multifunctional glass products and the characterization of photocatalytic self cleaning and antimicrobial properties. As semico...
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Tirkeş, Süha; Önal, Ahmet Muhtar (Elsevier BV, 2004-11-15)
New compounds consisting of 2- and 3-thienyl units linked by polyether bridges have been synthesized and their electrochemical polymerization was performed via constant potential electrolysis (CPE) in an electrolytic solution containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6)) dissolved in CH3CN. 2-Thienyl monomers (I and II), but not 3-thienyl monomers (III and IV), were also polymerized via chemical oxidation, which yielded broken pi-conjugated polymer products. The polymers were characteri...
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Synthesis of ferrocenyl-substituted pyrazoles via the reaction between (2-formyl-1-chlorovinyl)ferrocene and hydrazine derivatives is described. Depending upon the substitution pattern of hydrazine, the reaction affords 1-alkyl/aryl-5-ferrocenylpyrazoles and/or 1-alkyl/ aryl-3-ferrocenylpyrazoles. The reaction appears to be general for a variety of hydrazine derivatives.
Citation Formats
Ö. Yalçın, “Production of lactic acid esters by reactive distillation,” M.S. - Master of Science, Middle East Technical University, 2011.