• 공업화학
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• 제5권4호
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• pp.609-615
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• 1994

기체크로마토그래프에 직접 연결한 펄스 반응장치를 이용하여 10wt% $Ag/{\alpha}-Al_2O_3$ 촉매상에서 에틸렌 부분산화반응을 수행하였다. 산소가 분자흡착상태로 존재하기 어려운 실험온도에서 산소를 주입한 후 에틸렌을 주입하였을 때 산화에틸렌이 발생하였으며, 이 결과로부터 원자상태의 흡착산소가 산화에틸렌 생성에 관여함을 알 수 있었다. 흡착산소량과 몸체산소량을 감소시키면 산화에틸렌의 선택도는 감소하였다. 생성된 산화에틸렌은 에틸렌과 흡착산소로 분해되거나 아세트알데히드로 이성질화되었으나, 아세트알데히드로의 이성질화반응은 먼저 흡착된 산소에 의해서 크게 억제되었다.

• 청정기술
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• 제22권4호
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• pp.281-285
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• 2016

난분해성 1,4-다이옥산을 분해시키기 위하여 촉매습식과산화반응에 활성적인 Cu wire촉매를 사용하였다. Cu wire 촉매를 사용함으로써 1,4-다이옥산의 완전한 분해가 가능하였으나, 분해된 1,4-다이옥산은 완전 무기화($CO_2$와 $H_2O$로 전환)되지 못하고 중간생성물인 ethylene glycol diformate, oxalic acid, formic acid, formaldehyde, acetaldehyde 등으로 전환되었다. 1,4-다이옥산이 분해되어 없어짐에 따라 formaldehyde와 oxalic acid가 점진적으로 나타나기 시작하여 증가하다가 최고농도를 보인 후 다시 감소하였다. 이들 두 중간체의 최고농도 도달시점에 acetaldehyde의 농도가 급격히 증가하여 최고농도를 보인 후 다시 감소하였다. 이들 세가지 중간물질의 감소와 함께 ethylene glycol diformate, formic acid가 생성되기 시작하여 그 농도가 점진적으로 증가하였다. 이들은 연속적인 과정을 통해 생성되었다. Cu wire 촉매는 반응이 진행되는 동안 활성이 떨어지지 않고 매우 안정적이었다.

• 원예과학기술지
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• 제29권6호
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• pp.592-599
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• 2011

Plum is a climacteric fruit and softening is a serious problem for storage and transportation. Thus $1{\mu}L{\cdot}L^{-1}$ of 1-methylcyclopropene (1-MCP) was applied to plums to prolong their shelf life and maintain quality. Japanese plums (Prunus salicina cv. Formosa) were stored at $20^{\circ}C$ and $0^{\circ}C$ for 14 days and 46 days respectively, with or without 1-MCP treatment. Fruits were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP at $10^{\circ}C$ for 24 h. Ethylene production and respiration rate were strongly inhibited in 1-MCP-treated fruits at $20^{\circ}C$. It was also observed that there was less ethanol and acetaldehyde evaporation in 1-MCP-treated fruits stored at $20^{\circ}C$ compared to those in control fruits not treated with 1-MCP. Fruit qualities, such as firmness, titratable acidity (TA), skin color, and decay, changed more slowly in 1-MCP-treated fruits stored at $20^{\circ}C$ than in untreated fruits. There were no differences in the ethylene production or respiration rate between the groups of fruits stored at $0^{\circ}C$ throughout the experiment. Chilling injury was also inhibited by the application of 1-MCP during storage at $0^{\circ}C$. When the fruits stored at $0^{\circ}C$ with or without 1-MCP were transferred to $20^{\circ}C$ after 25 days, the differences in ethylene production and respiration rate, firmness, TA, TSS, and acetaldehyde and ethanol evaporation between the initial (after being stored at $0^{\circ}C$ for 25 days) and the final measurements (after being stored at $0^{\circ}C$ for 25 days and then transferred to $20^{\circ}C$ for three days) were lower in 1-MCP treated fruits than in non-treated fruits. The postharvest application of 1-MCP in Formosa plums showed positive effects at both $0^{\circ}C$ and $20^{\circ}C$ storage conditions with regard to quality, such as low ethylene production and low respiration rates, firmness, TA, ethanol, and acetaldehyde evaporation, chilling injury, and decay.

• 대한화학회지
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• 제19권6호
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• pp.423-427
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• 1975

에탄올의 산화반응중의 칼륨을 dope 한 산화아연의 전기전도의 변화를 250${\sim}350^{\circ}C$에서 측정하였다. 산화아연 상에서는 탈수소 및 탈수반응이 일어난다. 300$^{\circ}C$ 이상에서 $CO_2$의 생성과 이에 따르는 전기전도의 증가를 보였는데 이것은 아세트알데히드의 분해에 의해 생긴 CO의 산화반응에 의한 것이 아닌가 본다. 에탄올에 산소를 가하면 아세트알데히드의 생성은 증가하나 에틸렌의 생성에는 변화가 없었다. 이것은 주로 $O^-$로서 화학흡착 되어있는 산소가 에탄올 흡착과 이에 따른 탈수소 과정에 유리하게 작용하고 있는 것이 아닌가 한다.

• 원예과학기술지
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• 제35권3호
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• pp.300-313
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• 2017

'Unicon' cherry tomato (Solanum lycopersicum) is one of the most highly perishable horticultural crops due to its high water content and respiration rate. This study was carried out to assess the effect of continuous application of $CO_2$ (control [air], 3%, and 5%) on the quality and shelf life of cherry tomato fruits stored at $10^{\circ}C$ and $85{\pm}5%$ relative humidity (RH) at two maturity stages (pink and red). Continuous application of $CO_2$ did not affect the soluble solids content (SSC) or titratable acidity (TA) of the fruit at either maturity stage during storage. However, there was a significant difference among treatments in terms of flesh firmness, cell wall thickness, pectin content, vitamin C content, skin color, lycopene content, weight loss, ethylene production rate, respiration rate, and acetaldehyde and ethanol production. Fruits treated with 5% $CO_2$ maintained their high quality with regards to vitamin C, skin color ($a^*$), lycopene content, weight loss, physiological parameters (ethylene production rate, respiration rate, and volatile compounds), flesh firmness, cell wall thickness, and pectin content at both maturity stages compared with 3% $CO_2$ treatment and the control. Continuous application of $CO_2$ (5%) reduced the ethylene production rate and the production of volatile compounds during storage. Therefore, cherry tomato 'Unicon' fruit can be stored for two weeks without losing fruit quality at both maturity stages under continuous application of 5% $CO_2$ as a postharvest treatment.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3755-3761
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• 2013

This study aims to assess the ecological risk of the hazardous air pollutants (HAPs) emitted in the semiconductor manufacturing processes in Korea by using Quantitative Structure Activity Relationship (QSAR, EPA, US, EPI $Suite^{TM}$ 4.1). Owing to the absence of environmental standards of hazardous air pollutants in the semiconductor manufacturing processes in Korea, 18 HAPs in the semiconductor field included in both the US EPA NESHAPs and the hazardous air pollutant list of Ministry of Environment in Korea were selected. As a results 8 chemicals (44.4%) of the selected 18 HAPs were VOCs. Cyanides (cyanides) and ethylene oxides (epoxy resins), and tetrachloro-ethylene (aliphatic compounds, halides) showed long half-lives. Cyanide HAPs especially had the highest half-life with the estimated value of 356.533 days. Nickel compounds (heavy metal compounds) possessed the highest water solubility followed by acetaldehyde (aldehyde compounds), ethylene oxides, and 1,4-dioxanes. The halides, including tetrachloro-ethylenes, carbon tetra-chlorides, benzene (aromatic compounds), and lead (heavy metals), are estimated to take the longest time for biodegradation. Tetrachloroethylene, with the acute toxicity end point of 3.685-7.033 mg/L, was assessed to be the most highly toxic substance among the 18 HAPs. However, considering the absence of the HAPs in the common category of log $K_{ow}{\geq}4$and $BCF{\geq}500$, which indicates the standard of bioconcentration potentials, potentials of the bioconcentration are considered to be low.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.284-284
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• 2012

In this study, $V_2O_5/TiO_2$ catalyst was measured reactivity of ethanol when vanadia ratio was increasing. First, $V_2O_5/TiO_2$ catalyst was prepared to the increasing vanadia ($VO_x$) ratio as 0.2, 1, 10 wt%. And we were used X-ray diffraction (XRD), then not appear markedly peak to pure vanadia about XRD analysis. So we were decided vanadia that was evenly dispersed on $TiO_2$. Result about temperature-programmed reduction (TPR) analysis was obtained 3 reactions that was dehydrogenationfrom obtained to acetaldehyde, dehydration from obtained to ethylene, condensation from obtained to diethyl ether. If vanadia ratio was increasing in $V_2O_5/TiO_2$, reactions temperature of ethanol was known lower. And condensation into diethyl ether is quenched away with increasing vanadia loading. In addition, competition between reductive dehydration and oxidative dehydrogenation occurs, while the selectivity toward dehydrogenation is favored with increasing vanadia loading.

• 한국식품과학회지
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• 제32권6호
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• pp.1278-1284
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• 2000

본 연구는 60일간 MA저온저장 후 $2^{\circ}C$와 $25^{\circ}C$의 다른 유통 온도 조건에서 MA포장내 에틸렌 흡착제의 처리가 단감의 선도유지에 미치는 영향에 대하여 조사하였다. 저장 후 $25^{\circ}C$에서 폐쇄계 호흡측정방법으로 단감의 호흡량을 측정한 결과 에틸렌 흡착제 처리구가 무처리구에 비해 과실의 호흡량 증가를 완화시키는 것으로 조사되었다. 또한 MA 포장내 에틸렌 흡착제 처리가 유통 중 과실 품질에 미치는 영향을 조사한 결과 $25^{\circ}C$에서 에틸렌 흡착제 처리가 무처리구에 비해 포장내 $O_2$ 농도의 감소 및 $CO_2$ 농도의 증가를 억제시키는 것으로 조사되었다. 그러나 $2^{\circ}C$에서는 과실의 에틸렌 발생량이 적으므로 에틸렌 흡착제 처리가 포장지내 $O_2$ 및 $CO_2$ 농도 변화에 큰 영향을 미치지 않는 것으로 조사되었다. 또한 $25^{\circ}C$에서 포장내 에틸렌 흡착제 처리가 과실의 연화를 억제하는 효과가 있었다. 유리당 변화는 $25^{\circ}C$에서 포장내 에틸렌 흡착제 처리가 무처리구에 비해 sucrose의 감소를 억제시키는 효과를 보였다. 그러나 glucose 및 fructose는 에틸렌 흡착제 처리 시 유통 초기에는 오히려 무처리에 비하여 낮아지는 경향을 보였다. 과육내 에탄올과 아세트알데히드의 농도는 $25^{\circ}C$ 유통시 고농도의 에탄올 및 아세트알데히드 축적이 관찰되었으며, 에틸렌 흡착제 처리시 에탄올 및 아세트알데히드 농도는 감소하였으나 그 효과는 다른 품질 지표에 비하여 크지 않은 것으로 나타났다.

• 생물환경조절학회지
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• 제14권3호
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• pp.137-143
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• 2005

저장전 고온처리($38^{\circ}$, 48시간)는 참외의 당도, 산도, 비타민 C의 함량과 ${\alpha}$-tocopherol 활성을 높였으며, $3^{\circ}C$의 MA저장중 생체중 감소 이산화탄소, 에틸렌그리고 아세트알데히드 발생량을 낮게 유지시켰다. 또한 저장후 외관상 품질, 경도, 당도, 산도, 비타민 C, ${\alpha}$-tocopherol 활성 등 내적품질이 고온처리한 참외에서 높은 수준을 유지하였는데 특히 저온장해정도를 알 수 있는 이온용 출량이 고온처리구에서 낮아 수확후 고온처리로 저온장해가 완화되었음을 알 수 있었다. 고온처리를 하지 않은 대조구는 저장 25일부터 Alternaria rot이 발견되었으나 고온처리구는 저장 종료일인 39일까지 부패가 발견되지 않았으며 외관상 품질에 대한 저장일수로 세운 회귀식에 의하면 저장수명이 고온처리구에서 8일 이상 연장되었다. 참외의 경우 저장전 $38^{\circ}C$의 낮은 고온에서 장시간 열처리를 함으로써 살균효과 저온장해 완화효과와 더불어 수명연장까지 얻을 수 있었다.

• 한국환경과학회지
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• 제21권2호
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• pp.165-179
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• 2012

Indirect $CO_2$ effect due to non-methane volatile organic compound (NMVOC) emissions from solvent and product use and fugitive NMVOC emissions from fuels in the Republic of Korea and 13 Annex I countries under United Nations Framework on Climate Change were estimated and the proportions of them to total greenhouse gas (GHG) emissions ranged from 0.092% to 0.45% in 2006. Indirect greenhouse effect ($CO_2$, $CH_4$, and $O_3$) were estimated at 13 photochemical assessment monitoring sites in the Republic of Korea using concentrations of 8 NMVOCs of which indirect global warming potential (GWP) were available. The contribution of toluene to mixing ratio was highest at 11 sites and however, the contribution of toluene to indirect greenhouse effect was highest at nine sites. In contrast to toluene, the contributions of ethane, butane, and ethylene were enhanced. The indirect greenhouse effects of ethane and propane, of which ozone formation potentials are the lowest and the third lowest respectively among targeted 10 NMVOCs, ranked first and fourth highest respectively. Acetaldehyde has relatively higher maximum incremental reactivity and is classified as probable human carcinogen however, its indirect GWP ranked second lowest.