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Alcohol과 Silane으로 처리한 Silica의 표면특성 (II)
Surface Characteristics of Silica Treated with Alcohols and Silanes(II)
HWAHAK KONGHAK, August 1983, 21(4), 203-210(8), NONE
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Abstract
실리카를 실란유도체 및 알코올로 처리하여 흡착특성을 조하였다.
Shapiro와 Kolthoff가 제안한 실리카의 표면처리정도를 결정하는 방법으로 메틸레드 흡착을 시행한 결과, 메틸알콜 또는 디클로트메틸실란으로 처리된 실리카가 처리효과가 대체로 좋았고, 트리메틸 클로르실란, 디메디틸클로르실란, 트리클로르메틸실란 등 방대한 알킬기를 지닌 실란으로 처리된 경우는 효과가 좋지 않음을 나타내었다. 처리온도에 따른 효과는 모든 경우에 250∼300 ℃에서 가장 좋음을 알 수 있었다.
처리된 실리카의 암모니아 및 프로판에 대한 흡착등온선은 Brunauer의 5형식중 제II형을 잘 만족하였으며 흡착량은 표면의 히드록실기의 양에 비례하였다.
흡착량은 메틸알콜로 처리된 것이 가장 많았고, 트리클로르에틸실란으로 처리한 것이 가장 적었다. 첫 번째 흡착층은 형성하는 흡착열은 암모니아 흡착의 경우 6∼7 Kcal/mol이었다.
Shapiro와 Kolthoff가 제안한 실리카의 표면처리정도를 결정하는 방법으로 메틸레드 흡착을 시행한 결과, 메틸알콜 또는 디클로트메틸실란으로 처리된 실리카가 처리효과가 대체로 좋았고, 트리메틸 클로르실란, 디메디틸클로르실란, 트리클로르메틸실란 등 방대한 알킬기를 지닌 실란으로 처리된 경우는 효과가 좋지 않음을 나타내었다. 처리온도에 따른 효과는 모든 경우에 250∼300 ℃에서 가장 좋음을 알 수 있었다.
처리된 실리카의 암모니아 및 프로판에 대한 흡착등온선은 Brunauer의 5형식중 제II형을 잘 만족하였으며 흡착량은 표면의 히드록실기의 양에 비례하였다.
흡착량은 메틸알콜로 처리된 것이 가장 많았고, 트리클로르에틸실란으로 처리한 것이 가장 적었다. 첫 번째 흡착층은 형성하는 흡착열은 암모니아 흡착의 경우 6∼7 Kcal/mol이었다.
The adsorption properties of silicas treated with silane derivatives or alcohols have been investigated.
According to methylred adsorption method proposed by Shapiro and Kolthoff to determine the extent of modification of silica surface, methylalcohol or dichloromethyl silane treated silica was found most effectively modified. But the silicas treated by silanes which have bulky alkyl groups such as trimethylchloro silane, trichloroethyl silane, dimethyldichloro silane and ethylalcohol turned out to be less effective.
The adsorption isotherms for ammonia gas adsorbed on the modified silicas gave a better fit to type II isotherms among the Brunauer's five types of adsorption isotherms. And adsorption capacities were proportional to the amounts of the surface hydroxyl groups, it was found that methylalcohol treated silica had remarkable adsorption capacity, and trichorolethyl silane treated silica exhibited less capacity. The heats of adsorption for the first layer（Q1） of the modified silicas for ammonia adsorption were 6∼7 kcal/mol.
According to methylred adsorption method proposed by Shapiro and Kolthoff to determine the extent of modification of silica surface, methylalcohol or dichloromethyl silane treated silica was found most effectively modified. But the silicas treated by silanes which have bulky alkyl groups such as trimethylchloro silane, trichloroethyl silane, dimethyldichloro silane and ethylalcohol turned out to be less effective.
The adsorption isotherms for ammonia gas adsorbed on the modified silicas gave a better fit to type II isotherms among the Brunauer's five types of adsorption isotherms. And adsorption capacities were proportional to the amounts of the surface hydroxyl groups, it was found that methylalcohol treated silica had remarkable adsorption capacity, and trichorolethyl silane treated silica exhibited less capacity. The heats of adsorption for the first layer（Q1） of the modified silicas for ammonia adsorption were 6∼7 kcal/mol.
