• Elastomers and Composites
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• v.55 no.4
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• pp.263-269
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• 2020

Novel flexible terpolymers with a reactive moiety were synthesized by coordination polymerization with a metallocene catalyst and a cocatalyst system. C2-symmetric rac-Et(Ind)2ZrCl2 and tri-iso-butylaluminum/dimethylanilinium tetrakis (pentafluorophenyl) borate were employed as the catalyst and cocatalyst, respectively. We synthesized reactive terpolymers consisting of ethylene, a high α-olefin content (1-hexene, 1-octene, 1-decene, and 1-dodecene), and divinylbenzene. The structure and composition of the terpolymers were characterized by 1H-nuclear magnetic resonance analysis. The catalytic activity, polymer yield, molecular weight, and molecular weight distribution were measured as functions of the chain length and high content of α-olefins. Furthermore, the thermal properties and crystallinity of the terpolymers were determined by differential scanning calorimetry and wide-angle X-ray scattering.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.313-318
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• 1987

The approximate rate and stoichiometry of the reaction of excess Thexylbromoborane-methyl sulfide, $ThxBHBr{\cdot}SMe_2,$ with selected organic compounds containing representative functional groups under standardized conditions (methylene chloride, $0^{\circ}C)$ were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The selectivity of the reagent was also compared to the selectivity of thexylchloroborane-methyl sulfide. Thexylbromoborane appears to be a much milder and hence more selective reducing agent than thexylchloroborane. The reagent tolerates many organic functionalities. Thus, the reagent shows very little reactivity or no reactivity toward acid chlorides, esters, epoxides, amides, nitro compounds including simple olefins. However, this reagent can reduce aldehydes, ketones, carboxylic acids, nitriles, and sulfoxides. Especially the reagent reduces carboxylic acids including ${\alpha},{\beta}$ -unsaturated ones and nitriles to the corresponding aldehydes. In addition to that, thexylbromoborane shows good stereoselectivity toward cyclic ketones, much better than the chloro-derivative.

• Bulletin of the Korean Chemical Society
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• v.6 no.6
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• pp.366-369
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• 1985

The reactions of (E)-1-hexenylboronic acid (1) or (E)-${\beta}$-phenylethenylboronic acid (2) with various olefins in acetonitrile at room temperature in the presence of lithium palladium chloride and triethylamine gave the corresponding (E, E)-conjugated dienes stereospecifically in good yields. (E)-${\beta}$-Phenylethenylboronic acid (2) was more reactive than (E)-1-hexenylboronic acid (1) in these vinylations. And these vinylations were also carried out catalytically when 10 mol % of lithium palladium chloride and cupric chloride, as the reoxidant of palladium, or 10 mol % of palladium acetate and mercuric acetate were added instead of stoichiometric amount of lithium palladium chloride.

• Bulletin of the Korean Chemical Society
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• v.6 no.3
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• pp.153-157
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• 1985

A diacetylene compound, 1,4-diphenyl-1,3-butadiyne, was photolyzed with 2,3-dimethyl-2-butene, 1,4-cyclohexadiene, dimethyl fumarate, and methyl crotonate, as a model reaction of the phototoxic conjugated polyynes with DNA or RNA and [2 + 2] photocycloadducts were obtained except for 1,4-cyclohexadiene. In the photoreaction of 1,4-diphenyl-1,3-butadiyne with 2,3-dimethyl-2-butene, a [2 + 2 + 2] photoadduct was additionally obtained. The photolysis of 1,4-di-t-buyl-1,3-butadiyne with 2,3-dimethyl-2-butene also yielded a [2 + 2] photoadduct. Fluorescence was observed from all the photoadducts while the reactants did not show any fluorescence.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.138-144
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• 2015

Effects of Co/Al and Si/Al molar ratios of cobalt incorporated SAPO-34 catalysts (CoAPSO-34) on their catalytic lifetime were investigated in dimethyl to olefin (DTO) reaction. The property of CoAPSO-34 catalysts was characterized using XRD, SEM, $^{29}Si$ MAS NMR, and $NH_3$-TPD techniques. First, the lifetime of CoAPSO-34 prepared by varying Co/Al molar ratios was improved than that of using the SAPO-34 catalyst, and the optimal Co/Al molar ratio was 0.0025. The total acid site amounts increased from 0.432 to 1.111 mmol/g with increasing Si/Al molar ratios from 0.05 to 0.20 while fixing a Co/Al molar ratio of 0.0025. However, the catalysts with too high acid site amounts were deactivated rapidly with blockages of the pores due to the fast accumulation of polycyclic aromatic hydrocarbons in the cage. Therefore, the CoAPSO-34 catalyst with a proper Si/Al molar ratio of 0.10 was the most superior in terms of the lifetime, which was improved by about 87% as compared with that of the SAPO-34 catalyst.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.679-689
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• 2009

Light olefins are very important hydrocarbons widely used as the raw materials of the most petrochemicals including plastics and medicines. In addition, the nation's olefin production capacity is regarded as one of the key indicators to predict the nation's economic scale and growth. Steam cracking of naphtha (or called "NCC (Naphtha Cracking Center) technology"), the traditional process to produce light olefins, is one of the most consuming energy processes among the chemical industries. Therefore, this process causes tremendous $CO_2$ emission. To reduce the energy consumption and $CO_2$ emission from NCC process, the present paper, firstly, investigates and analyses some alternative technologies which can be potentially substituted for traditional process. Secondly, applying the alternative technologies to NCC process, their effects such as energy savings, $CO_2$ emission reduction and CER (Certified Emission Reduction) were estimated. It is found that the advanced NCC process can reduce approximately 35% of SEC (Specific Energy Consumption) of traditional NCC process. This effect can lead to the reduction of 3.3 million tons of $CO_2$ and the acquisition of the 128 billion won of CER per year. Catalytic cracking of naphtha technology, which is other alternative processes, can save up to approximately 40% of SEC of traditional NCC process. This value equates to the 3.8 million tons of $CO_2$ mitigation and 147 billion won of CER per year.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1371-1380
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• 2007

Study on the instability of waste plastic's thermal pyrolysis oil was carried out for the purpose of improving its quality. The reaction of pyrolysis oil with ozone changed double bonds into aldehydes and ketone, estimated that HDPE pyrolysis oil contained $\sim45$ wt% 1-alkene type olefins, and PP pyrolysis oil did $\sim73$ wt% olefins, which consisted of $\sim47$ wt% secondary and $\sim20$ wt% primary alkenes. The dark brown color and odor of pyrolysis oil were improved by eliminating double bonds, indicated that they were directly related to unsaturated hydrocarbons. Container test showed that metal can affected oil quality worse than the brown glass bottle. Antioxidant added into pyrolysis oil was consumed up to 90% within $2\sim3$ days and the wt. composition of unsaturated hydrocarbons in pyrolysis oil was not changed within 50 days, inferring that instability of pyrolysis oil due to unsaturated bonds can be stabilized by antioxidants. Adsorption test on silica gel, activated carbon and alumina to remove precipitates in oil produced a good result, but not enough to remove moisture. However, cheap anhydrous sodium carbonate showed the best removal efficiency of moisture as well as precipitates in oil. Therefore the pyrolysis oil quality improvement was accomplished by applying anhydrous $Na_2CO_3$ into the production plant.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.291-300
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• 2008

Catalytic cracking of n-octane was carried out over H-ZSM-5 zeolite catalysts after calcination with air and steaming with 100% steam in the temperature range of $550-750^{\circ}C$ for 24 h and compared with the results of thermal cracking. The increase of calcination and steaming temperature resulted in the decrease of surface area, pore volume, and strong acid sites, which was mainly caused by the dealumination of H-ZSM-5 framework. It was found by $^{27}Al$ and $^{29}Si$ MAS NMR that the dealumination was proceeded through the transformation process of tetrahedral framework Al${\rightarrow}$penta-cordinated Al ${\rightarrow}$ octahedral framework Al and the phenomena was much more severe in steaming conditions than that of calcination. In the catalytic cracking of n-octane, as the temperatures of calcination and steaming were increased, the conversion of n-octane, the selectivity of light olefins and ethylene to propylene ratio were decreased due to the dealumination of framework aluminum resulting the loss of acidic strengths. The conversion, selectivity of light olefins and ethylene to propylene ratio reached almost to the level of thermal cracking after steaming at $750^{\circ}C$ for 24 h.

• Journal of the Korean Chemical Society
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• v.38 no.4
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• pp.295-301
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• 1994

The Ru(Ⅲ), Ni(Ⅱ), Cu(Ⅱ), and Pd(Ⅱ) complexes of N$_4$-polydentate ligands(meso-Me$_6$-[14]-ane, rac-Me$_6$-[14]-ane, and cyclam) have been prepared and their catalytic activity and selectivity in the oxidation of olefins in the presence of oxidant such as NaOCl, H$_2$O$_2$, t-BuOOH, and PhIO studied. The oxidations of cyclohexene, 1-hexene, cyclooctene, 1-octene, and styrene as substrates have been investigated gas chromatographically. The Ru(Ⅲ)-N$_4$ complexes showed high selectivity for epoxide in the catalyzed oxidation of olefins with NaOCl. The catalytic activities of Ru(Ⅲ)-N$_4$ complexes were discussed in terms of the flexibility of N$_4$-polydentate ligands, the Ru(Ⅲ)-Cl bond interaction and the steric effect of oxidants. The oxidation of 1-octene using PhIO as oxidant was carried out to verify. The Pd(Ⅱ) complex turned out to be more active catalyst than the Ni(Ⅱ) complexes.

• Polymer(Korea)
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• v.25 no.4
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• pp.468-475
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• 2001

For copolymerization of ethylene and norbornene initiated by various metallocene catalysts such as $rac-Et(Ind)_2ZrCl_2,\;rac-Me_2Si(Ind)_2ZrCl_2,\;rac-Me_2Si(Cp)_2ZrCl_2,\;and\;(n-BuCp)_2ZrCl_2$ with modified methylaluminoxane(MMAO) cocatalyst, the ${\alpha}$-olefins such as 1-hexene(H), 1-octene and 1-decene were added as a 3rd monomer. In this situation, the effects of the polymerization condition, the catalyst structure as well as the structure and the amount of added ${\alpha}$-olefin on the catalyst activity as well as the properties and structure of polymer were examined. As results, it was found that the catalyst activity and thermal property of polymer depended on not only catalyst structure but also ${\alpha}$-olefin structure. For $rac-Et(Ind)_2ZrCl_2/MMAO$ catalyst system, it was possible to get high activity and controllable $T_g$ of polymer. Among ${\alpha}$-olefins, H as a 3rd monomer exhibited the maximum enhancement in catalyst activity.