• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.531-537
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• 1992

The approximate rates and stoichiometry of the reaction of excess potassium 2-thexyl-1,3,2-dioxaborinane hydride(KTDBNH) with 55 selected compounds containing representative functional groups under standardized conditions (tetrahydrofuran, TEX>$0^{\circ}C$, reagent : compound=4 : 1) was examined in order to define the characteristics of the reagent for selective reductions. Benzyl alcohol and phenol evolve hydrogen immediately. However, primary, secondary and tertiary alcohols evolve hydrogen slowly, and the rate of hydrogen evolution is in order of $1^{\circ}$> $2^{\circ}$> $3^{\circ}$. n-Hexylamine is inert toward the reagent, whereas the thiols examined evolve hydrogen rapidly. Aldehydes and ketones are reduced rapidly and quantitatively to give the corresponding alcohols. Cinnamaldehyde is rapidly reduced to cinnamyl alcohol, and further reduction is slow under these conditions. The reaction with p-benzoquinone dose not show a clean reduction, but anthraquinone is cleanly reduced to 9,10-dihydro-9,10-anthracenediol. Carboxylic acids liberate hydrogen immediately, further reduction is very slow. Cyclic anhydrides slowly consume 2 equiv of hydride, corresponding to reduction to the caboxylic acid and alcohol stages. Acid chlorides, esters, and lactones are rapidly and quantitatively reduced to the corresponding carbinols. Epoxides consume 1 equiv hydride slowly. Primary amides evolve 1 equiv of hydrogen readily, but further reduction is slow. Tertiary amides are also reduced slowly. Both aliphatic and aromatic nitriles consume 1 equiv of hydride rapidly, but further hydride uptake is slow. Analysis of the reaction mixture with 2,4-dinitrophenylhydrazine yields 64% of caproaldehyde and 87% of benzaldehyde, respectively. 1-Nitropropane utilizes 2 equiv of hydride, one for hydrogen evolution and the other for reduction. Other nitrogen compounds examined are also reduced slowly. Cyclohexanone oxime undergoes slow reduction to N-cyclohexylhydroxyamine. Pyridine ring is slowly attacked. Disulfides examined are reduced readily to the correponding thiols with rapid evolution of 1 equiv hydrogen. Dimethyl sulfoxide is reduced slowly to dimethyl sulfide, whereas the reduction of diphenyl sulfone is very slow. Sulfonic acids only liberate hydrogen quantitatively without any reduction. Finally, cyclohexyl tosylate is inert to this reagent. Consequently, potassium 2-thexyl-1,3,2-dioxaborinane hydride, a monoalkyldialkoxyborohydride, shows a unique reducing characteristics. The reducing power of this reagent exists somewhere between trialkylborohydrides and trialkoxyborohydride. Therefore, the reagent should find a useful application in organic synthesis, especially in the field of selective reduction.

• Journal of odor and indoor environment
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• v.16 no.2
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• pp.187-198
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• 2017

It is very important to treat infected livestock carcasses safely and quickly. In this study, the degradation characteristics and odor generation characteristics of carcasses were investigated during the treatment of swine carcasses using the anaerobic burial composting method. While the carcasses were decomposed, the temperature remained high, at $40{\sim}55^{\circ}C$ on average, and most of the carcasses were decomposed rapidly. The major odor-contributing substances in the buried composting method are sulfuric odor substances such as $H_2S$, $CH_3SH$, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), and the odor contribution of these substances is 93~99%. Among them, $CH_3SH$, which accounts for about 56~89% of odor contribution, was the most representative indicator substance. Despite the anaerobic digestion process, the methane concentration in the digestion process was as low as 0.5~0.8% at the burial point of the carcass. The odor and methane produced during the decomposition of the carcasses decreased considerably during the discharge to the surface layer through the buried layer consisting of compost. These results suggest that anaerobic high temperature burial composting is one of the most useful methods to treat carcasses of infected livestock.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.158-164
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• 2006

Offensive odor from CAFO(concentrated animal feeding operation) and its control have become a significant issue in Korea. Control of odors from the CAFO requires to identify major odorant and their generation mechanisms. In this study, an easy method to collect gas sample and to quantify its odorants is proposed. The method involves on-site odorant extraction with solid-phase microextraction and quantitation with GC/MSD or GC/FID. Analytes of the current study include: trimethylamine(TMA), carbon disulfide($CS_2$), dimethyl sulfide(DMS), dimethyl disulfide(DMDS), acetic acid(AA), propionic acid(PA) and n-butyric acid(BA). The resulting linearity($R^2$) of calibration curve for each analyte was good over the range from several ppbv to ppmv; 0.984 for TMA(0.056-1.437), 0.996 for $CS_2$(0.039-0.999), 0.994 for DMS(0.029-0.756), 0.995 for DMDS(0.024-0.623), 0.992 for AA(0.068-1.314), 0.955 for PA(0.047-0.940), and 0.976 for BA(0.036-0.712). Method detection limits were 5.67, 6.39, 5.78, 25.2, 0.098, 0.363 and 0.099 ppbv for AA, PA, BA, TMA, DMS, $CS_2$, and DMDS, respectively. With the developed method, odorants from poultry, swine, and cattle barns were analysed. All the compounds but DMDS were detected from the sample collected in the poultry barn, and their levels exceeded the representative published human olfactory threshold.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.646-651
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• 1998

The molecular structure of sulfur compounds and the retention relationship are studied by gas chromatography. Analyzed sulfur compounds are, hydrogen sulfide, sulfur dioxide, carbon disulfide, ethyl mercaptan, dimethyl sulfide, iso-propyl mercaptan, normal propyl mercaptan, ethyl methyl sulfide, tert-butyl mercaptan, tetrahydrothiophene, thiophene, and 2-chlorothiophene. Multiple linear regression explains the retention relationship of molecular descriptors. In GC the temperature program is 30$^{\circ}C$ held for 10.5 min, and then increased to 150$^{\circ}C$ at a rate 15$^{\circ}C$/min. Predicted equation for relative retention time (RRT) using SAS program is as follows; $RRT=0.121bp+14.39dp-8.94dp^2+0.0741sqmw-35.78\; (N=8,\; R^2=0.989, \;Variance=0.175,\;F=66.21)$. RRTs are function of boiling point, the square root of molecular weight, molecular dipole moment, and boiling point effects mostly on RRT. The RRT is maximized at the molecular dipole moment of 0.805D, when using nonpolar columns. The planar and highly symmetric compounds are eluted slowly. The square, of correlation coefficient $(R^2)$ using SAS program, is 0.989, and the variance is 0.175 in training sets. For three sulfur compounds, the variance between observed RRTs and predicted RRTs is 0.432 in testing sets.

• Journal of Life Science
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• v.22 no.8
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• pp.1071-1076
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• 2012

To investigate the antimicrobial and anti-halitosis effects of Alnus firma extracts and gallic acid (GA) isolated from A. firma, we measured their antimicrobial activities against oral pathogens and their inhibitory effects on the cell adhesiveness and acid production of oral pathogens. In addition, the levels of volatile sulfur compounds were determined by using oral chroma. The dichloromethane (DCM) fraction has broad antimicrobial activity, and the ethylacetate (EA) fraction showed a relatively high level of antimicrobial activity against Streptococcus mutans and Porphyromons gingivalis. Especially, the GA and DCM fractions had significant inhibitory effects on the attachment and acid production of S. mutans and Streptococcus salivarius, respectively. The 2% MeOH extract of A. firma showed a significant inhibitory effect on the production of volatile oral compounds, such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide, which can cause bad breath and halitosis. Two percent GA also had a significant inhibitory effect on the production of hydrogen sulfide. Our study showed that the active fractions and GA of A. firma could be suitable resources for development as a natural antibiotic agent for the treatment of infectious oral diseases.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.157-163
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• 1987

Changes in the odor components of Sergia Lucens during fermentation were studied by simultaneous distillation and extraction method. Forty seven components were identified by GC and GC-MS. Major cooked odor components of raw material were alkyl pyrazines and thialdine. Alkyl pyrazines, furfuryl alcohol, isoamyl alcohol and sulfide compounds, such as dimethylsulfide and dimethyltrisulfide increased during the period of fermentation. On the other hand, thialdine content decreased as the period of fermentation was extended. Sensory evaluation of cooked Sergia Lucens odor was carried out by GC-sniff analysis. The odors of GC effluents at the sniffing port were sniffed in order to find out the key compound of cooked Sergia Lucens odor components. The results of the GC-sniff analysis indicated that 2,5-dimethylpyrazine, 2,6-dimethylpyrazine and 2,3-dimethylpyrazine had dried or roast shrimp-like odor and thialdin had dried small sardine-like odor. The result showed that pyrazines and thialdine could play an important role in the formation of cooked Sergia Lucens odor.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E2
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• pp.107-120
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• 2002

Dimethyl sulfide (DMS) is the major sulfur gas released from the ocean. The atmospheric DMS released from the ocean is oxidized mainly by hydroxyl (OH) radical during the day and nitrate (NO$_3$) radical at night to form sulfur dioxide (SO$_2$) as well as other stable products. The oxidation mechanism of DMS via OH has been known to proceed by two channels; abstraction and addition channels. The major intermediate product of the addition channel has been known to be dimethylsulfoxide (DMSO) based on laboratory chamber studies and field experiments. However, a branching ratio for DMSO formation is still uncertain. The reaction of DMSO with OH ultimately produces SO$_2$and dimethylsulfone. The major product of the abstraction channel has known to be SO$_2$from laboratory chamber studies. But overall conversion efficiency for DMS to SO$_2$from DMS oxidation is still inconsistent in the literature. Based on laboratory and field studies, the conversion efficiency from the abstraction channel is likely to be greater than 0.5, while that from the addition channel is likely to be greater than 0.6. Overall conversion efficiency from DMS to SO$_2$might be greater than 0.5 based on the above two values in the remote marine boundary layer (MBL). This high efficiency in the remote MBL is supported by strong coupling between DMS and SO$_2$measurements with high temporal resolution.

• Journal of Korean society of Dental Hygiene
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• v.8 no.2
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• pp.13-22
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• 2008

The purpose of this study is to analyze the correlation between cause and the element of mouth odor through measurement and identification of mouth odor and is to apply to effective method for elimination of halitosis, Subjects were 150 people who visited Dong Pusan College and lived in Pusan Cross-sectional survey was used and mouth odor was measured by Oralchroma. Oral examination proceeded with status of tongue plaque distribution and calculus index, Statistical analysis was performed with SPSS version 13.0 for window Among 150 people, 67.3% subjects thought they had halitosis, 89.3% people felt that their mouth odor were the severest as soon as wake-up, Tongue was serious place for halitosis by 53.3% subjects Methylmercaptan and dimethyl sulfide showed the highest correlation by 0.549 index score, Moreover, methyl mercaptan was observed the correlation with brushing time in 0.190 index score and with food intake in 0.177(P<0.05). In conclusion, brushing time and food intake were correlated with mouth odor.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.804-807
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• 2007

The acid gas removal (AGR) system was designed and installed to remove $H_2S$ in coal syngas in the pilot-scale coal gasification system for producing chemicals like Dimethyl Ether(DME). The syngas from the coal gasification at the rate of $100{\sim120$ $Nm^3$/hr included pollutants such as fly ash. $H_2S$, COS, $NH_3$, etc. The designed temperature and pressure of the AGR system are below 50oC and 8 kg/$cm^2$. Fe-chelate was used as an absorbent. $H_2S$ was stably removed below 0.5 ppm in the AGR system when the concentration of $H_2S$ was $150{\sim}450$ ppm. The pH of Fe-chelate solution was also stably maintained between $8{\sim}9$. FeMgO absorbent was also tested to remove $H_2S$ in the lab-scale AGR system and $H_2S$ was also removed below 0.5 ppm in the initial operation.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.4
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• pp.594-598
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• 2016

We studied airborne contaminants (airborne particulates and odorous compounds) emitted from compost facilities in South Korea. There are primarily two different types of composting systems operating in Korean farms, namely mechanical aerated pile composting (MAPC) and aerated static pile composting (SAPC). In this study, we analyzed various particulate matters (PM10, PM7, PM2.5, PM1, and total suspended particles), volatile organic compounds and ammonia, and correlated these airborne contaminants with microclimatic parameters, i.e., temperature and relative humidity. Most of the analyzed airborne particulates (PM7, PM2.5, and PM1) were detected in high concentration at SAPC facilities compered to MAPC; however these differences were statistically non-significant. Similarly, most of the odorants did not vary significantly between MAPC and SAPC facilities, except for dimethyl sulfide (DMS) and skatole. DMS concentrations were significantly higher in MAPC facilities, whereas skatole concentrations were significantly higher in SAPC facilities. The microclimate variables also did not vary significantly between MAPC and SAPC facilities, and did not correlate significantly with most of the airborne particles and odorous compounds, suggesting that microclimate variables did not influence their emission from compost facilities. These findings provide insight into the airborne contaminants that are emitted from compost facilities and the two different types of composting agitation systems.