• Elastomers and Composites
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• v.35 no.4
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• pp.288-295
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• 2000

It has been tried to decrease the crosslink density of vulcanized EPDM (ethylone-propylene-diene terpolymer) rubber through a chemical devulcanization treatment. Phase transfer catalyst, alkali metal (i.e., sodium), and triphenylphosphine have been used as a chemical agent ul the devulcanization treatment. Also it has been estimated the effect of the devulcanization treatment in the case of utilization of 2-butanol as a devulcanization reaction solvent. In the devulcanization treatment using quaternary ammonium salt as a phase transfer catalyst. the devulcanization effect has been studied with the variation of catalyst molecular weight and the choice of bromide or chloride cation. In the devulcanization treatment using sodium, it has been estimated the devulcanization treatment effect depending upon the variation of reaction variables such as amount of sodium used, reaction temperature, pressure of hydrogen gas, which is used as a reaction environment. The $M_c$ value (number average molecular weight between two crosslink points) has been experimentally estimated by the equilibrium swelling method and it is quantitatively related to the crosslink density. The estimation of devulcanization effect for vulcanized EPDM rubber has been carried out by the comparison of the $M_c$ values between the untreated and the treated specimens.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.585-590
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• 2003

Cobalt oxygen carrier complex N,N'-ethylenebis(3-methoxysalycylideneiminato)cobalt(II), Co(3MeOsalen) was prepared at $25{\circ}C$. UV and visible absorption spectra of the complex and hydrazobenzene were studied in non-aqueous solvent methanol in the range of wavelength 200-600 nm. The oxidation of hydrazobenzene by oxygen in non-aqueous solvent is catalysed by Co(3MeOsalen). In the presence of triphenylphosphine($PPh_3$), the rate decreases in methanol. This is presumably attributable to the coordination of $PPh_3$ to the Co(3MeOsalen), resulting in the catallytically inactive compound. The initial rates of the oxidation of hydrazobenzene with the ligand triphenylphosphine were measured by the theoretical values of the rates, Rate=$k_1+k_2K_1[P]/1+K_1[P]+K_1K_2[P]^2$. This fact would be a poorer σ-donor ligand than methanol.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.615-626
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• 2016

In the paper, mild solvent soluble alkyl group modified epoxy resins were prepared via a three-step method; (1) the condensation reaction of dodecyl phenol (DP) and formaldehyde, (2) the crosslinking reaction of dodecyl phnol novolac compound (DPC) and bisphenol A diglycidyl ether, (3) the dodecyl phenol novolac epoxy resins containing fatty acid (DPFA) was prepared by introducing fatty acid to DPC. Equivalent ratios of DP and formaldehyde were 1.25~1.333/1.0. Equivalent ratio of DPC and bisphenol A diglycidyl ether (YD-128) was 1.0/2.0. Reactivity, viscosity, molecular weight, solvent solubility, and physical properties of DPFA were investigated. The result show that as the number of aromatic ring of DPFA increased, viscosity increased and solvent solubility improved. When we test the properties of coatings by blending the synthesized DPFA with a white pigment, DPFAC-5 using triphenylphosphine (TPP) as a ring-open catalyst showed optical performance for drying time, adhesion, hardness, impact resistance, acid resistance and storage stability.

• Journal of the Korean Chemical Society
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• v.24 no.1
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• pp.34-43
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• 1980

The reaction of thianthrene cation radical perchlorate with thioxanthene in acetonitrile gave thianthrene and dark reddish thioxanthylium ion instead of thioxanthene cation radical. Addition of aromatic nucleophiles such as anisole, aniline, N,N-diethylaniline, catechol, ethylbenzene, to the above mixture yielded the corresponding thioxanthenes with substituent at 9 position. Reactions with dibenzo-18-crown-6-ether, diphenylmercury, and triphenylphosphine gave similar products. However, reactions with aromatics with electron-withdrawing group were either too slow or inert to such a reaction.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1542-1548
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• 2006

Maleimide modified epoxy compounds were prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with diglycidylether of bisphenol-A. Triphenylphosphine was used as catalyst and methylethylketone as solvent. The resulting compound possessed both the oxirane ring and maleimide group. The curing reaction of the maleimide epoxy compound with amine curing agents such as 1-(2-aminoethyl) piperazine (AEP) and 5-amino-1,3,3-trimethylcyclohexane methylamine isophorone diamine, IPDA) were studied. Incorporation of maleimide groups in the epoxy resin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples were found to have good thermal stability, chemical resistance (acid/alkali/solvent) and water absorption resistance.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2066-2070
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• 2009

$Cl_3CCONH_2$ coupled with $PPh_3$ was determined to be an effective reagent for the conversion of carboxylic acids to their corresponding acid chlorides. Subsequently, these acid chlorides were successfully trapped with amines in the presence of 4-picoline, yielding amides. This practical and efficient protocol can be utilized for the synthesis of biological amides in excellent yields.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.194-199
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• 2000

The chemical behavior for Mo(0) and W(0) complexes, [M(CO)$_2$(PPh$_3$)$_4$] (M=Mo and W),has been investigated by UV-vis spectroscopic, magnetic, and electrochemical methods. Three absorption bands are observed in the UV-spectra. The crystal-field-splitti ng energy, spin-pairing energy, and bond strengths were deduced from the spectra. The metal d electrons in both complexes seemed to be delocalized in low-spin state.Metal ligand correlation appeared to strongly depend on bond strengths and diamagnetic properties. In electrochemical processes, both complexes exhibit an irreversible reduction wave.

• YAKHAK HOEJI
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• v.52 no.4
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• pp.311-315
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• 2008

The synthesis of 7-arylidene cephalosporanates for ${\beta}-lactamase$ inhibitor was described. The reactions of substituted benzyl halides $[1]{\sim}[3]$ with triphenylphosphine gave triphenylphcsphonium chlorides $[4]{\sim}[6]$. These phosphonium salts were treated with n-butyllithium to give ylides, which were reated with 7-oxocephalosporanate [7] by Wittig reaction to afford the 7-exomethylene cephalosporanates $[8]{\sim}[10]$. These cephalosporanates were oxidized to cephalosporanate sulfones $[11]{\sim}[13]$ with mCPBA. The deprotection of benzhydryl cephalosporanate $[8]{\sim}[13]$ with $AlCl_3$ and $NaHCO_{3}$ gave sodium salts of 7-arylidene cephalosporanates $[14]{\sim}[19]$.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.820-822
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• 2013

N,N,N',N'-Tetrabromobenzene-1,3-disulfonamide (TBBDA)/$PPh_3$ and N,N,N',N'-tetrachlorobenzene-1,3-disulfonamide (TCBDA)/$PPh_3$ are two highly reactive reagent systems for the conversion of alcohols corresponding into alkyl chlorides and bromides in moderate to excellent yields in dichloromethane at room temperature under mild and neutral conditions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.96-99
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• 2004

Silica fillers were coated by plasma polymer coatings of 1,3-diaminopropane, allylamine, pyrrole, 1,2-epoxy-5-hexene, allyl mercaptan and allyl alcohol using RF plasma (13.56 MHz). The coated fillers were then mixed with biphenyl epoxy, phenol novolac (curing agent) and/or triphenylphosphine (catalyst), and subjected to DSC analyses in order to elucidate the chemical reaction between functional moieties in the plasma polymer coatings and the epoxy resin. Only the samples with 1,3-diaminopropane and allylamine plasma polymer coated silica fillers showed heat of reaction peaks when they were mixed with biphenyl epoxy resin only, while these samples as well as the samples with 1,3-diaminopropane, allylamine and pyrrole plasma polymer coated silica fillers exhibited heat of reaction peaks when mixed with both biphenyl epoxy and phenol novolac (curing agent).