Crude oil - Genyu

Unrefined petroleum produced from underground. It is a viscous reddish-brown or dark brown liquid. Its specific gravity is 0.8 to 1.0. It is a complex mixture of various hydrocarbons, with paraffin (alkane) and naphthene (cycloalkane) hydrocarbons predominating, and aromatic hydrocarbons being rare. It also contains organic compounds of sulfur, nitrogen, and oxygen, and the higher the boiling point fraction, the greater the content of these impurities. Paraffin-based crude oil is made up primarily of paraffinic hydrocarbons, and has a relatively low specific gravity and a high wax content. Naphthene-based crude oil is made up primarily of naphthenic hydrocarbons, and has a relatively high specific gravity and generally contains a lot of asphalt. Crude oil with a particularly high asphalt content is also called asphalt-based crude oil. In reality, there are many crude oils with properties intermediate between these two, and these are called intermediate- or mixed-base crude oils. Representative examples of intermediate-base crude oils include Pennsylvania crude oil from the United States and various crude oils from the Middle East, while American Gulf Coast crude oil and Baku crude oil from Azerbaijan are naphthene-based, and American Midcontinent crude oil. Japan produces crude oil in the Niigata, Akita, and Yamagata prefecture regions, but the quantities are small and more than 99.7% of demand is dependent on imported crude oil. Middle Eastern crude oil, which accounts for the majority of this, has a high sulfur content (about 1.5-3.5%).

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

地下から産出した状態の未精製の石油．赤褐色ないし黒褐色の粘ちゅうな液体である．比重0.8～1.0．主成分は各種炭化水素の複雑な混合物であるが，とくにパラフィン(アルカン)およびナフテン(シクロアルカン)炭化水素が多く，芳香族炭化水素は少ない．このほか，硫黄，窒素，酸素の各有機化合物を含み，これらの不純物は高沸点留分ほど含有量が多い．とくにパラフィン炭化水素を主成分とするものをパラフィン基原油とよび，比重は比較的小さく，ろう分を多く含む．また，ナフテン炭化水素を主成分とするものをナフテン基原油とよび，比重は比較的大きく，一般にアスファルト分を多く含み，とくにアスファルト分の多いものは，アスファルト基原油ともいわれる．実際には，これらの中間的な性質をもつ原油が多く，これらは中間基または混合基原油とよばれる．アメリカのペンシルベニア原油，および中東地方の各原油はパラフィン基，アメリカのガルフコースト原油，アゼルバイジャンのバクー原油はナフテン基，アメリカのミドコンチネント原油は中間基原油として代表的なものである．わが国では，新潟，秋田，山形県地方に原油を産出するが，その量は少なく，需要の99.7％ 以上は輸入原油に依存している．とくにその大部分を占める中東原油には，硫黄分が多い(約1.5～3.5％)．

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