【Daily Question】October 14, 2016 – Participate to earn +2 wealth； +3 to +10 wealth for correct answers
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To increase the popularity of the chemical analysis section, a \"One Question per Day\" campaign has been launched to foster an active atmosphere for technical exchanges while offering rewards in the form of financial benefits to users. 【Daily Question】 (Single-choice question) What is the relationship between the cetane number of diesel and its hydrocarbon composition? ( ) A. Diesel with a higher content of isomeric alkanes has a higher cetane number; B. Diesel with a higher content of alkanes has a higher cetane number. C. Diesel with a high content of aromatic hydrocarbons has a high cetane number: D. Diesel with a high content of isoparaffinic hydrocarbons and aromatic hydrocarbons has a high cetane number: The correct answer is B. Reply with your answer; participating in the quiz earns you +2 wealth points. If you get all answers correct, you’ll receive an additional +3 to +8 wealth points. Those who provide thorough analyses and explanations for the questions or answers, or who include detailed calculation processes, will receive extra wealth points as a reward. If your answer is correct and your analysis is accurate, it will be marked as the best reply (or the best assistance). Feel free to answer the questions.
B. Diesel with a high content of alkanes has a high cetane number.
For various hydrocarbons of type B, the trend in their cetane numbers is as follows: among hydrocarbons with the same number of carbon atoms, n-alkanes have the highest cetane numbers; alkenes, isomers, and cycloalkanes have intermediate values; whereas aromatic hydrocarbons, especially those with complex ring structures, have the lowest cetane numbers. The higher the degree of isomerization of hydrocarbons and the greater the number of rings, the lower their cetane number ； As the length of the side chains attached to naphthenes and aromatic hydrocarbons increases, their cetane number rises, whereas as the number of side chain types increases, the cetane number decreases. Therefore, the cetane number of diesel produced from paraffin-based crude oils such as Daqing crude is higher than that of diesel produced from naphthenic-based crude oils such as Gudao crude. Catalytically cracked and coker diesel have a low cetane number due to their high content of aromatic hydrocarbons, especially polycyclic aromatic hydrocarbons.
Among hydrocarbons with the same number of carbon atoms, n-alkanes have the highest cetane number; alkenes, isomers, and cycloalkanes have a cetane number in between; while aromatic hydrocarbons, especially those with fused rings, have the lowest cetane number. The higher the degree of isomerization of hydrocarbons and the greater the number of rings, the lower their cetane number ； As the length of the side chains attached to naphthenes and aromatic hydrocarbons increases, their cetane number rises; whereas as the number of types of side chains increases, the cetane number decreases
B. Diesel with a high content of alkanes has a high cetane number
D. Diesel with a high content of isomeric alkanes and aromatic hydrocarbons has a high cetane number:
The relationship between the cetane number of diesel and its hydrocarbon composition is as follows: (B) A. Diesel with a high content of isomeric alkanes has a high cetane number; B. Diesel with a high content of alkanes has a high cetane number. C. Diesel with a high content of aromatic hydrocarbons has a high cetane number: D. Diesel with a high content of isoparaffinic hydrocarbons and aromatic hydrocarbons has a high cetane number:
B. Diesel with a high content of alkanes has a high cetane number.
D. Diesel with a high content of isomeric alkanes and aromatic hydrocarbons has a high cetane number:
D. Diesel with a high content of isomeric alkanes and aromatic hydrocarbons has a high cetane number: