• Korean Journal of Metals and Materials
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• v.48 no.2
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• pp.141-147
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• 2010

An Ni-Al intermetallic coating has been produced by induction heating on mild steel. The effect of the induction heating conditions on the microstructure of the coating has been investigated. The reaction synthesis of the intermetallic compounds was promoted while increasing the heating rate and the holding time at reaction temperature. Especially, an NiAl phase corresponding to the initial composition of mixed powder was predominantly formed. However, the synthesis at low reaction temperatures occurred by solid state diffusion during the holding time and an Fe-Al reaction layer was formed at the interface with the substrate, regardless of the heating rate. The combustion synthesis of the intermetallic compound occurred at a temperature higher than 1023 K and resulted in an almost single phase NiAl structure.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.981-983
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• 2010

The condensation of several aromatic/heteroaromatic aldehydes with 2-aminothiophenol catalyzed by silica sulfuric acid under microwave irradiation afforded 2-arylbenzothiazoles in high yields and short reaction times under solvent-free conditions. The major advantages of the present method are good yields, ecofriendly, reusable catalyst, mild and solvent-free reaction conditions.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2969-2972
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• 2009

A mild and efficient method has been developed for condensation of substituted phenol with ${\beta}$-ketoester in the presence of catalytic amount of ammonium metavanadate (10 mol%) at ambient temperature to afford the corresponding substituted 4-methyl-2H-chromen-2-one in high yields under mild conditions. Utilization of commercially available inexpensive catalyst makes this manipulation very interesting from an economic perspective.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.787-792
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• 2011

Under mild conditions and without any additional organic solvent, synthesis of carbamatoalkyl naphthols could be carried out in the present of two halogen-free Br${\phi}$nsted acidic ionic liquids, 3-methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate and N-(4-sulfonic acid)butylpyridinium hydrogen sulfate. A wide range of aromatic aldehydes easily undergo condensation with $\beta$-naphthol and methyl or benzyl carbamate to afford the desired products of good purity in excellent yields. The present methodology offers several advantages such as a simple procedure with an easy work-up, short reaction times, and excellent yields. The catalysts could be recycled and reused for several times without substantial reduction in their catalytic activities.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2970-2972
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• 2011

One-pot homo- and cross-coupling reactions of arenediazonium tosylate salts bearing a halogen group have been exploited for the synthesis of biaryls and polyaryls under mild conditions. $Pd(OAc)_2$ has proven to be an efficient catalyst for the successful dual transformation of diazonium salts into p-quaterphenyl (3).

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1743-1748
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• 2014

A facile and effective method has been developed for the synthesis of a novel series of benzofuran derivatives via N-acylation, O-alkylation and intramolecular condensation reactions, starting from readily available substituted o-hydroxy aryl ketone, and chloroacetyl arylamides. This metal-free transition process is characterized by mild reaction conditions, atom economy, short reaction time and a high yield with a decreased amount of by-products.

• YAKHAK HOEJI
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• v.40 no.6
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• pp.659-665
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• 1996

Zinc white is mainly used as a mild astringent, protectant. and has weak antiseptic action. It is well known that the yield of zinc white produced is greatly affected by the syn thetic conditions such as the reactant concentration, reaction temperature, washing water temperature, mole ratio of reactants, and drying temperature, calcination temperature, etc. The purpose of this study is to investigate the optimal synthesis conditions of zinc white produced. A randomized complete block design suggested by G.E.P. Box and K.B. Wilson was applied for this purpose. Basic zinc carbonate was prepared by reacting zinc sulfate and sod. carbonate solution in this study. Zinc white comes when prepared by calcination of basic zinc carbonate. The optimum synthesis conditions of zinc white obtained from this study is as follows: 1) The reacting temperature range is: 92-100$^{\circ}C$, 2) The concentration of reactant solution is 23.6-27%, 3) The optimum mole-ratio: [ZnSO4]/[Na2CO3] is 1.74~1.96, 4) The washing water temperature is 36$^{\circ}C$, 5) The drying temperature range is 68-74$^{\circ}C$, 6) The calcination temperature is 600$^{\circ}C$. The outcome of DSC indicated a desolvation of basic zinc carbonate occurred at about 133.3$^{\circ}C$. The dehydration of the compound ceased at about 267.9$^{\circ}C$ and the decarboxylation ceased at about 379.9$^{\circ}C$. The physical and chemical properties of zinc white as medicine were studied by use of Volume Test.

• Journal of the Korean Chemical Society
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• v.52 no.5
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• pp.511-514
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• 2008

• Advances in materials Research
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• v.5 no.3
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• pp.171-179
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• 2016

Fusion and characterization of bisphenol-A diglycidyl ether based thermosetting polymer mortars containing an epoxy resin, Fly ash and Rock sand are presented here for the Experimental study. The specimens have been prepared by means of an innovative process, in mild conditions, of commercial epoxy resin, Fly ash and Rock sand based paste. In this way, thermosetting based hybrid mortars characterized by a different content of normalized Fly ash and Rock sand by a homogeneous dispersion of the resin have been obtained. Once hardened, these new composite materials show improved compressive strength and toughness in respect to both the Fly ash and the Rock sand pastes since the Resin provides a more cohesive microstructure, with a reduced amount of micro cracks. The micro structural characterization allows pointing out the presence of an Interfacial Transition Zone similar to that observed in cement based mortars. A correlation between micro-structural features and mechanical properties of the mortar has also been studied.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.236-242
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• 1998

Reaction of carbonyl compounds with Al-alkoxydiisobutylalane (DIBAOR, R=H, Et, i-Pr, t-Bu) has been investigated in detail so as to establish their usefulness as selective reducing agents in organic synthesis. The reagents appear to be extremely mild and can reduce only aldehydes and ketones effectively under mild conditions. All the other common organic functional groups are not affected by these reagents. The reagents can also reduce α,β-unsaturated aldehydes and ketones to the corresponding allylic alcohols without any detectable 1,4-reduction. Furthermore, the reagents show a highly chemoselective discrimination between aldehyde and ketone, between aldehydes, and between ketones. Even more remarkable is the stereoselective reduction of cyclic ketones to the thermodynamically more stable alcohol epimers.