• Polymer(Korea)
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• v.39 no.3
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• pp.487-492
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• 2015

The effects of chemical structure of alkyl groups of norbornene carboxylic alkyl esters(methyl, octyl, 4-chlorobenzyl) and endo/exo ratios of norbornene monomers on activity of palladium catalyst and polymerization behavior were investigated. Norbornene ester monomers were synthesized from the reaction of 5-norborene-2-carboxylic acid and various alcohols. Polymerization catalyst, di-${\mu}$-chloro-bis(-methoxybicyclo[2,2,1]-hept-2-ene)palladium(II) (DCBMP), was synthesized according to the literature procedure and silver hexafluoroantimonate ($AgSbF_6$) was used as a conjugate anion source. Gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) were the principal techniques for polymer characterization and $^1H$ NMR spectroscopy was used for chemical structures determination of monomers and polymers. For all of the norbonene alkyl esters GPC data showed that when the amounts of endo isomers exceeded those of exo isomers decreased molecular weight polymers were obtained probably due to the decreased catalyst activity. Polymerizations were conducted by varying the monomer/catalyst mole ratios (100:1, 200:1, 300:1). When 300:1 monomer/catalyst ratio was employed it was possible to synthesize high molecular weight ($M_n=27500g/mol$), film forming polymer from exo-norbornene carboxylic acid octyl ester.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.89-94
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• 2009

The efficiency of heterogeneous catalysts has been investigated in ozonation process for organic removal. Heterogeneous catalytic ozonation was conducted for the degradation of humic acid in the presence of Granular Activated Carbon or Zeolite as a solid catalyst. And the results were compared to those of ozonation alone and adsorption alone without ozonation. The degradation characteristics of humic acid in each process were examined with the values of pH, TOC, $UV_{254}$ and $COD_{Cr}$.

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.263-266
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• 2001

Isopropylation of phenol with 2-propanol has been carried out over Na-exchanged ZSM-5 zeolites to determine the effect of catalyst acidity on phenol conversion and product selectivity. The acid type and strength of the catalyst such as Lewis, weak and strong Bronsted acid sites are measured by pyridine adsorbed XPS and the catalytic properties are interpreted in terms of the acid properties. The active site and mechanism for the reaction are suggested based on evidence of study from the reactant adsorbed FT-IR.

• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.179-185
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• 2009

The esterification of the reactants of Jatropha oil and methanol added by propyleneglycol was done using p-TSA catalyst. And then the emulsification of triglyceride and methanol was conduced by 1.0vol% GMS. The emulsified reactants were transesterified at $65^{\circ}C$ using TMAH and mixed catalyst (50wt%-TMAH+50wt%-NaOH) respectively. The esterification conversion at the 1:8 molar ratio of free fatty acid to methanol using 8.0wt% p-TSA was 94.7% within 80min. The overall conversion at the 1:8 molar ratio of mixed fat(50wt% Beef Tallow) to methanol and $65^{\circ}C$ using mixed catalyst was 95.4% The cloud point of Biodiesel decreased with the addition of petroleum diesel.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.418-421
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• 2006

Fatty acid methyl esters, also referred to as biodiesel, have been determined to have a great deal of potential as substitutes for petro-diesel. In order to enhance productivity in the biodiesel production process, feedstocks were previously recommended to be anhydrous, with a free fatty acid content of less than 0.5%. In this study, the effects of several catalysts, methanol molar ratio, catalyst amount, and reaction time on the reduction of free fatty acid level were studied with a simulated feedstock consisting of 20% oleic acid in rapeseed oil. Ferric sulfate was selected as the best catalyst. Increasing the catalyst amount and methanol molar ratio is very effective in decreasing the acid value of the simulated mixture. Our results may provide useful information with regard to the development of more economic and efficient free fatty acid removal system.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.415-421
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• 2009

Esterification reaction between succinic acid[SA] and 1,4-butanediol [BD} was kinetically investigated in the presence of organic metal catalysts (alkyl-silver oxide(ASO),CAT 100E) at $150{\sim}190^{\circ}C$. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order kinetics with respect to the concentration of reactants and catalyst, respectively. The overall reaction order was 2nd. From the examination of relationship between apparent reaction rate constants and reciprocal absolute temperature, the activation energy has been calculate as 146.70 kJ/mol with ASO catalyst and 43.04 kJ/mol with CAT 100E catalyst.

• Journal of the Korean Chemical Society
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• v.57 no.4
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• pp.425-431
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• 2013

Oxidation of glutamic acid is performed in aqueous acid media at $30^{\circ}C$ under the kinetic condition [glutamic acid]$_T{\gg}[Cr(VI)]_T$. Effect of combination of micellar catalyst (SDS, TX-100) and promoter (PA, bpy, phen) has been studied. Among the promoters phen accelerates the reaction most in aqueous media. But the rate acceleration is small in the case. Combination of promoter and catalyst produces much better result. Maximum rate enhancement occurs in presence of the combination of bpy and SDS.

• Korean Journal of Materials Research
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• v.33 no.7
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• pp.265-272
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• 2023

In this study, the synthesis of nitrobenzene was carried out using sulfated silica catalyst. The study delved into H₂SO₄/SiO₂ as a solid acid catalyst and the effect of its weight variation, as well as the use of a microwave batch reactor in the synthesis of nitrobenzene. SiO₂ was prepared using the sol-gel method from TEOS precursor. The formed gel was then refluxed with methanol and calcined at a temperature of 600 ℃. SiO₂ with a 200-mesh size was impregnated with 98 % H₂SO₄ by mixing for 1 h. The resulting 33 % (w/w) H₂SO₄/SiO₂ catalyst was separated by centrifugation, dried, and calcined at 600 ℃. The catalyst was then used as a solid acid catalyst in the synthesis of nitrobenzene. The weights of catalyst used were 0.5; 1; and 1.5 grams. The synthesis of nitrobenzene was carried out with a 1:3 ratio of benzene to nitric acid in a microwave batch reactor at 60 ℃ for 5 h. The resulting nitrobenzene liquid was analyzed using GC-MS to determine the selectivity of the catalyst. Likewise, the use of a microwave batch reactor was found to be appropriate and successful for the synthesis of nitrobenzene. The thermal energy produced by the microwave batch reactor was efficient enough to be used for the nitration reaction. Reactivity and selectivity tests demonstrated that 1 g of H₂SO₄/SiO₂ could generate an average benzene conversion of 40.33 %.

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1247-1256
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• 2010

Since biodiesel as bioenergy is defined as ester compounds formed by esterification of animal/vegetable oils, in this study three vegetable cooking oils (market, waste and refined waste ones) were esterified by reactions of alkali catalyst and immobilized enzyme. The fatty acid composition of the formed ester compounds was analyzed to investigate the feasibility of biodiesel production. By lipolysis (i.e, hydrolysis of Triglyceride (TG)), all three vegetable oils used in this study were found to produce Diglyceride (DG), Monoglyceride (MD) and Fatty acid ethylester (FAEE). However, the amount of produced FAEE (which can be used as an energy source) was in the increasing order of market cooking oil, waste one and refined waste one. With NaOH catalyst, FAEE was produced about 24.92, 17.63 and 11.31 % for the respective oils while adding Lipozyme TL produced FAEE about 43.54, 38.16 and 24.47 %, respectively. This indicates that enzyme catalyst is more effective than alkali one for transesterification. In addition, it was found that the composition of fatty acids produced by hydrolysis of TG was unchanged with alkali and immobilized enzyme reactions. Thus it can be expected that stable conditions remain in the course of mixing with gasoline whose composition is similar to that of the fatty acids.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.313-315
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• 2019

A new synthetic method for N-hydroxysuccinimide (NHS), which is widely used in fine chemical and cosmetic industries, was developed. In a conventional synthesis, NHS is obtained by reacting $NH_2OH$ with succinic anhydride in a yield of about 70% using strong acid as a catalyst, which has an advantage of obtaining NHS relatively easily. However, it is expensive because of using a high cost succinic anhydride. In order to overcome this issue, we developed a new synthetic method for NHS with a moderate yield of 80% using a low cost succinic acid instead of succinic anhydride, alongside a stable Lewis acid catalyst, Zn acetate. As a result of the economic evaluation, it was confirmed that the cost reduction effect was about 15%.