• Journal of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.268-274
• /
• 1991

The rate constants for the nucleophilic addition reactions of thiourea to ${\beta}$-nitrostyrene derivatives(p-H, p-Cl, p-CH$_3$, p-OCH$_3$, p-NO$_2$) were determined by UV spectrophotometer and rate equations which can be applied over a wide pH ranges were obtained. On the basis of substituent effect, general base catalysis and rate equations, a reaction mechanism was proposed and revealed quantitively. Above pH 9.00, sulfide anion adds to the double bond(Michael type addition) and between pH 7.00 and 9.00, the neutral molecules and its anions add to the double bond competitively. Below pH 7.00, the addition reaction to double bond is initiated by the addition of neutral thiourea molecule.

• Journal of Adhesion and Interface
• /
• v.15 no.1
• /
• pp.22-30
• /
• 2014

Self-photoinitiating acrylate (SPIA) which can undergo self-initiation under UV irradiation was synthesized by a Michael addition in the presence of a base catalyst. The SPIA polymerizations were investigated by photo-differential scanning calorimeter (photo-DSC) and surface physical properties such as pendulum hardness and pencil hardness. The results showed that the SPIA can cure upon UV irradiation by itself without a photoinitiator. But we found out that both the curing rate and the conversion were too low for the self-curing reaction of SPIA. In order to improve the SPIA curing properties, we introduced the SPIA/cationic hybrid system and observed the effects of the addition of commercial free radical type monomer and photoinitiator on the curing behaviors. SPIA/cationic hybrid system was the best suitable to improve the SPIA curing properties. The kinetic analysis indicated that the cationic monomer and photoinitiator apparently accelerated the cure reaction and rate of the hybrid SPIA system, mostly due to the synergistic effect of cationic monomer and photoinitiator increasing the mobility of active species and the generation of reactive species (free radical, cation) during the photopolymerization process. The physical properties showed that, unlike typical free radical system, the hybrid systems did not show oxygen inhibition effect because of cationic reaction on the coating surface.

• Journal of Adhesion and Interface
• /
• v.21 no.1
• /
• pp.14-19
• /
• 2020

In this study, we synthesized a self-photocuring intermediate(SPI) by Michael addition reaction and synthesized polyurethane acrylate oligomer. Analysis and physical properties of the synthesized SPI and polyurethane acrylate oligomer were confirmed by FT-IR, NMR and UTM. As the content of the SPI increased, the tensile strength increased and the elongation decreased. In addition, since the film was hydrophobic, the surface energy tended to decrease. When the content of the SPI was 40 wt%, adhesion, processability, and pencil hardness were excellent, and solvent resistance was excellent overall.

• Journal of the Korean Chemical Society
• /
• v.40 no.8
• /
• pp.571-578
• /
• 1996

Iron alkynyl(amino)carbene complexes, (${\beta}$-aminovinyl)carbene complexes, ${\eta}^3$-(2-(alkylcarbonyl)vinyl)carbene complexes, and a 3-aminoallenylidene complex were formed in the reactions of iron alkynyl(ethoxy)carbene complexes with amines. The ratio of the products, which were formed by substitution reaction, the Michael addition of amines, rearrangements after the addition reaction, and the addition followed by the elimination of the ethoxy group, respectively, was dependent on reaction temperature, the substituent of the alkynyl moiety, and employed amines.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.4
• /
• pp.1170-1176
• /
• 2012

An efficient one-pot synthesis of acridinediones by $In(OTf)_3$-catalyzed reactions was developed starting from ${\beta}$-enaminones, aldehydes, and cyclic 1,3-diketones. The key strategies of these reactions involve domino Knoevenagel condensation/Michael addition/cyclodehydration reaction.

• Journal of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.120-126
• /
• 1989

The Kinetics of hydrolysis of styrylphenylsulfone derivatives in 50% methanol-water at 25$^{\circ}$C and ionic strength of 0.10 was investigated by UV spectrophotometry in the pH range of 0.0-14.0. The rate equations, which can be applied over a wide pH range, were obtained. The Hammett rho constants for the hydrolysis are 1.85 at pH 7.0 and 1.54 at pH 13.0, respectively. On the basis of the evidence, it is proposed that the general base-catalysis occurs in the hydrolysis of styrylphenylsulfone derivatives; above pH 11.0, Michael type nucleophilic addition take place, while below pH 9.0, the reaction is initiated by addition of water and from pH 9.0 to pH 11.0 these two reactions occur com-petitively.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.12
• /
• pp.2487-2490
• /
• 2008

• Bulletin of the Korean Chemical Society
• /
• v.3 no.4
• /
• pp.162-165
• /
• 1982

The rate constants of the nucleophilic addition of thioglycolic acid to the derivatives $(H,\;p-CH_3,\;p-CH_3O,\;p-Cl,\;p-NO_2)$ of ${\beta}$-nitrostyrene were determined by ultraviolet spectrophotometry. The rate equations which can be applied over a wide pH range were obtained. Therefrom a reaction mechanism was proposed. Above pH 8.5 sulfide anion adds to the double bond (Michael type addtion). However, below pH 8.5, the neutral molecule and $HSCH_2COO^{\theta}$ add to the double bond.

• Journal of the Korean Chemical Society
• /
• v.53 no.3
• /
• pp.308-324
• /
• 2009

The present work is devoted to study the interaction of $\beta$-aroylacrylic acid derivative (3) with malononitrile in (DMF) in the presence of piperidine and/or ammonium acetate, then using the formed compounds as starting materials for synthesizing fused and isolated heterocyclic systems. It has been established that the $\beta$-aroylacrylic acid (3) reacts with malononitrile in (DMF) in the presence of piperidine as a catalyst with the formation of 4H-pyran derivative (4). By changing the catalyst into ammonium acetate, pyridine derivative (5) has been obtained. Also the N-maleamic acid derivatives (19) and (27) have been synthesized via the interaction of (4) and (5) with maleic anhydride. The purpose of this step is to study the behavior of the formed maleamic acid derivatives – as analogies of $\beta$-aroylacrylic acids – towards different active methylene compounds under Michael addition reaction.

• Journal of the Korean Chemical Society
• /
• v.44 no.2
• /
• pp.120-126
• /
• 2000

The rate constants for the hydrolysis of 2-phenyl-4H,5H-3-methyl-3-thiazolinium perchlorate(PTP) derivatives were detemined by the use of ultraviolet visible spectrophotometer in water. The rate equations which could be applied over a wide pH ranges were obtained. On the basis of rate equation, hydrolysis product analysis, general base catalysis, and substituent effect, a plausible mechanism of the hydrolysis is proposed: Below pH 4.0, the reaction is initiated by addition of water, while above pH 9.0, Michael type nucleophilic addition takes place. In the pH range of $4.5{\sim}8.0$, these two reactions appear to occur competitively.