• 한국산업보건학회지
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• 제21권2호
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• pp.82-89
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• 2011

Methylcyclohexane is frequently used in industrial sites (2,592tons/year) as rubber adhesives, ink, paint thinners, organic solvents, and so on. However, there are limited data on the toxic evaluation of methylcyclohexane. This study aims to predict the hazards and neurological effects of methylcyclohexane using SD rats in order to prevent health disorders of workers. The OECD Guideline for Testing of Chemicals (OECD, 2001) was used as a reference during the tests. For 13 weeks (once a day, five days per week) 0, 10, 100 and 1,000mg/kg/day of methylcyclohexane was injected to SD rats to observe any changes in the body or organ weight, hematology, histopathology, mobility, blood pressure, and neurotransmitter. As a result, some male and female SD rats injected with 1,000mg/kg/day of methylcyclohexane died. On the other hand, surviving rats showed significant changes such as hematological changes involving the decrease in the number of red blood corpuscles, and the decrease or increase in the weight of the lungs, kidneys, spleens, and livers (p< 0.05, p<0.01). Also histopathological lesions were observed in the hearts and kidneys. In the test for the effect on the nervous system, SD rats injected with 100mg/kg/day of methylcyclohexane had higher blood pressure levels compared to the control group. However, no abnormal effects was observed in the mobility, serotonin, neurotransmitter, and the biopsy of the brain and coronary arteries. The study results revealed that the livers, hearts, and kidneys were affected by methylcyclohexane. The absolute toxic dose of methylcyclohexane is 1,000mg/kg/day, NOAEL is 100 mg/kg/day, and it is not a toxic substance to the nervous system.

• 한국수소및신에너지학회논문집
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• 제15권2호
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• pp.152-158
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• 2004

Hydrogen has been considered as an important and essential future energy source. But the storage of the hydrogen is a difficult problem and many studies were focused on this matter. However, the MTH-system (methylcyclohexane, toluene, hydrogen) was proposed for storage of hydrogen by Taube et al. and that is the reaction of hydrogen with toluene to give methylcyclohexane. One toluene molecule can store six hydrogen atoms to form methylcyclohexane. In this form the hydrogen can be easily stored in liquid organic hydrides and transported at ambient pressure in tanks. Hence, this study is focused on the catalytic dehydrogenation of methylcyclohexane. Since supported platinum and nickel were employed as catalysts in literature, in this study, porous Pt and Ni were prepared and tested for the dehydrogenation reaction. When the porous Pt catalyst was applied to the dehydrogenation it showed higher activity in the reaction and higher selectivity to toluene. Specially at higher pressure, it showed almost 100 % conversion and 100 % selectivity and hence porous platinum could be considered as best for the given reaction.

• 한국음향학회지
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• 제17권6호
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• pp.3-7
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• 1998

Methylcyclohexane의 초음파 흡수측정을 0.1-2MHz의 주파수 범위, 온도 30-60℃에 걸쳐 1MHz이하에서 정확한 초음파 흡수측정이 가능한 광 회절 초음파 공명법을 사용하여 행하였다. 그 결과, axial과 equatorial에 의한 완화는 단일 완화현상을 보였고 그 스펙트럼 으로부터 완화 주파수와 완화강도를 결정하였다. 완화 주파수의 온도 의존성으로부터 활성 화에너지(△H*)=10.0㎉/㏖을, 완화 강도의 온도 의존성에서 엔탈피 차(△H)=1.8㎉/㏖을 각각 구하였다.

• Safety and Health at Work
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• 제2권3호
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• pp.290-300
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• 2011

Objectives: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods: Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results: In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion: When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.

• Environmental Analysis Health and Toxicology
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• 제21권2호
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• pp.173-184
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• 2006

From the harmfulness expectation test conducted through a toxicity anticipation program, methylcyclohexane turned out to be harmful and simulative, but no carcinogenicity was anticipated. In a four-hour acute inhalation toxicity test, the result showed that lethal concentration ($LC_{50}$) was 3,750 ppm (15,054 mg/L), which was identified as a harmful substance on the basis of the harmful substance classification standard $2 of the Industrial safety and health law. methylcyclohexane fell under the category $4(2,500 substance from the GHS standard acute toxicity harmfulness classification. Also, from subchronic inhalation toxicity test that included 6 hours a day, five days a week, and for 13 weeks, we could observe weight, activity, long term weight, blood and blood biochemical influence from the exposure of test substance. No-observed effect level (NOEL) was determined below $100{\sim}400ppm$ inboth male and female. This material falls under the Category 2 ($50{\sim}250ppm/6hours/90days$) in the GHS (Globally Harmonized System) standard trace long-term whole body toxicity repeated exposure, and can be classified as a harmful substance in accordance with the Industrial Safety and Health Law harmful substance standard $NOEL{\leq}0.5mg/L/6hr/90day$ (rat).

• 한국산업보건학회지
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• 제21권1호
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• pp.33-39
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• 2011

The present study was carried out to investigate the potential acute toxicity of methylcyclohexane (MCH) by a single oral dose in female rats. The test chemical was administered once by gavage to female rats at dose levels 0, 1,250, 2,500, and 5,000 mg/kg. Mortalities, clinical findings, and body weight changes were monitored for the 14-day period following the administration. At the end of 14-day observation period, all animals were sacrificed and complete gross postmortem and histopathological examinations were performed. Treatment-related clinical signs, as evidenced by depression, soft feces, decreased locomotion activity, solid perineal region, crouching position, and anorexia were observed in all treatment groups in a dose-dependent manner. At the dose level of 5,000 mg/kg, decreased or suppressed body weight gain was found during the study period. At the scheduled necropsy, one case of congestion of the intestine and an increase in the weights of liver and kidney were observed in the 5,000 mg/kg group. Histopathological examinations exhibited an increased incidence of glomerular atrophy, congestion/hemorrhage, and focal degeneration/necrosis in the liver and an increased incidence of congestion, and inflammatory cell infiltration in the kidney. On the basis of the results, it was concluded that a single oral administration of MCH resulted in some adverse effects on clinical sign, body weight gain, and organ weight and histopathology in the liver and kidney in female rats. In the experimental conditions, the minimal lethal dose ($LD_{10}$) of MCH was greater than 5,000 mg/kg.

• 청정기술
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• 제26권4호
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• pp.279-285
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• 2020

Laboratories and industrial processes typically involve the use of flammable substances. An important property used to estimate fire and explosion risk for a flammable liquid is the flash point. In this study, flash point data at 101.3 kPa were determined using a SETA closed cup flash point tester on the following solvent mixtures: {2,2,4-trimethylpentane + methylcyclohexane}, {2,2,4-trimethylpentane + ethylbenzene}, and {2,2,4-trimethylpentane + p-xylene}. The purpose of this work is to obtain flash point data for binary mixtures of 2,2,4-trimethylpentane with three hydrocarbons (methylcyclohexane, ethylbenzene, and p-xylene), which are representative compounds of the main aromatic hydrocarbon fractions of petroleum. The measured flash points are compared with the predicted values calculated using the GE models' activity coefficient patterns: the Wilson, the Non-Random Two-Liquid (NRTL), and the UNIversal QUAsiChemical (UNIQUAC) models. The non-ideality of the mixture is also considered. The average absolute deviation between the predicted and measured lower flash point s is less than 1.99 K, except when Raoult's law is calculated. In addition, the minimum flash point behavior is not observed in any of the three binary systems. This work's predicted results can be applied to design safe petrochemical processes, such as identifying safe storage conditions for non-ideal solutions containing volatile components.

• 월간산업보건
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• 통권118호
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• pp.23-23
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• 1998

• 한국추진공학회지
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• 제15권5호
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• pp.1-9
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• 2011

비행체 속도를 증가시키기 위한 극초음속 항공기 기술 연구가 그동안 진행되어 왔다. 하지만 비행체의 속도증가는 비행체 구조의 변형을 유발할 수 있는 열적부하를 야기한다. 이러한 열적부하 처리를 위해 탄화수소형 흡열연료를 이용한 비행체 냉각에 대한 연구가 미국, 프랑스, 러시아 등 선진국에서 이루어지고 있다. 흡열연료(Endothermic fuels)는 열분해 또는 촉매분해와 같은 흡열반응(Endothermic reaction)을 통해 열을 흡수하는 액체 탄화수소 비행체 연료이다. 본 연구에서는 흡열연료의 모델연료로써 methylcyclohexane, n-octane, n-dodecane을 선정하여 흡열특성 연구를 진행하였다. 실험조건은 흡열연료가 사용되는 각 연료의 초임계 조건이며 온도별 분해율 분석, 열분해 생성물분석, 흡열량 계산을 수행하였다. 본 연구의 목표는 모델연료의 흡열특성을 규명함으로써 실제 비행체에 널리 사용되는 케로신 연료의 흡열특성 예측에 기여하는 것이다.

• 한국추진공학회지
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• 제18권2호
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• pp.10-15
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• 2014

극초음속 비행체는 속도가 증가할수록 공기와의 마찰열과 엔진열이 증가한다. 이러한 열적부하는 비행체 구조물의 변형을 야기하고 오작동을 유발할 수 있다. 흡열연료는 액체 탄화수소 연료로써 열분해 반응, 촉매분해 반응과 같은 흡열반응을 통해 열을 흡수할 수 있는 연료이다. 본 연구에서는 methylcyclohexane을 모델연료로써 선정하여 흡열특성을 측정하는 연구를 수행하였다. 반응열을 향상시키기 위해 제올라이트를 적용하였고 HZSM-5가 흡열량 향상에 가장 효과적인 것을 확인하였다. 본 연구의 목적은 흡열량 향상에 미치는 촉매의 영향을 연구하는 것이다. 이 촉매는 케로신연료를 흡열연료로써 사용하는 시스템에 적용될 수 있을 것이다.