【Daily Question】April 01, 2016: What is the chemical composition of petroleum?
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This post was last edited by B0SS on 2016-4-2 01:48. Replying to this post earns 3 wealth points, and an additional 5 points for correct answers! ! ! “\"Oil\" is as described in \"Dream Pool Essays\" by Shen Kuo (1031–1095), an outstanding scientist of the Northern Song Dynasty in China: it \"forms at the edges of waterways among sand and stones, mixing with spring water and emerging gradually.\" Abroad, oil is called “the devil’s sweat” and “glowing water”. So, the question is: what is the chemical composition of oil? Oil is primarily composed of two elements: carbon (C) and hydrogen (H). The carbon content ranges from 83% to 87%, while the hydrogen content ranges from 11% to 14%; together, these two elements account for 95% to 99% of the oil’s composition. Hydrocarbons, which are compounds made up of carbon and hydrogen, are the main substances that are processed and utilized during oil refining. In addition, oil also contains sulfur (S), nitrogen (N), and oxygen (O). The content of these non-hydrocarbon elements is generally 1–4%. Promotion of petrochemical-related activities: 1. Contest for suggestions on segmenting topics – http://bbs.hcbbs.com/thread-1568416-1-1.html (Source: Haichuan Chemical Forum) 2. [Petrochemical Weekly] Issue No. 9, dated 3-12-2016 (Summary of recent petrochemical activities) – http://bbs.hcbbs.com/thread-1568615-1-1.html (Source: Haichuan Chemical Forum) 3. “Haichuan Gratitude Season” – Summary of events in the Petrochemical Section – http://bbs.hcbbs.com/thread-1533218-1-1.html (Source: Haichuan Chemical Forum) 4. Summary of professional “basic knowledge” posts in the Petrochemical Section (Supported by the main forum; amazing prizes await you) – http://bbs.hcbbs.com/thread-1557057-1-1.html (Source: Haichuan Chemical Forum)
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Oil is primarily composed of two elements: carbon and hydrogen, with carbon accounting for 83%–87% and hydrogen accounting for 11%–14%; together, these two elements make up 95%–99% of oil’s composition. It also contains sulfur, nitrogen, oxygen, as well as trace amounts of non-metallic elements and other metallic elements such as vanadium, nickel, iron, copper, arsenic, chlorine, phosphorus, silicon, etc. By \"trace amounts,\" it is generally meant quantities in the order of parts per million. The various elements mentioned above combine in crude oil in different forms to form hydrocarbon and non-hydrocarbon compounds. Therefore, it can also be said that oil is a mixture composed of hydrocarbon and non-hydrocarbon compounds.
Oil is composed of a mixture of hydrocarbons such as alkanes, cycloalkanes, and aromatic hydrocarbons
What is the chemical composition of petroleum? A complex mixture mainly composed of hydrocarbons ； The elemental composition (by mass percentage) of crude oil is generally as follows: carbon 83.0%～87.0%, hydrogen 11.0%～14.0%, and sulfur, nitrogen, and oxygen 1%～5%
The chemical elements that make up petroleum are primarily carbon (83% ~ 87%) and hydrogen (11% ~ 14%); the rest include sulfur (0.06% ~ 0.8%), nitrogen (0.02% ~ 1.7%), oxygen (0.08% ~ 1.82%), as well as trace metal elements such as nickel, vanadium, and iron. Hydrocarbons, formed by the combination of carbon and hydrogen, constitute the main component of petroleum, accounting for approximately 95% to 99%, with a carbon-to-hydrogen atom ratio of 1.65–1.95. Compounds containing sulfur, oxygen, and nitrogen are harmful to petroleum products and should be removed as much as possible during petroleum processing. In oils from different sources, the structure and proportion of various hydrocarbons vary greatly, but they mainly belong to three categories: alkanes, cycloalkanes, and aromatic hydrocarbons. Oil that is primarily composed of alkanes is referred to as paraffinic oil ； Those composed mainly of naphthenes and aromatics are called cycloalkyl petroleum ； What lies between the two is called intermediate base oil.
The chemical elements that make up oil are primarily carbon (83%–87%) and hydrogen (11%–14%); the rest include sulfur (0.06%–0.8%), nitrogen (0.02%–1.7%), oxygen (0.08%–1.82%), as well as trace metal elements such as nickel, vanadium, and iron. In crude oil, these elements do not exist in a free state but are present in various compound forms, mainly hydrocarbon compounds, with small amounts of non-hydrocarbon compounds containing oxygen, sulfur, and nitrogen. Generally, crude oil contains sulfur, paraffins, resins, and asphalts. Hydrocarbons that are solid at carbon atom counts of around 15 to 42 in crude oil are called waxes. The percentage of wax in crude oil is known as the wax content. Resins are hydrocarbons with high molecular weights present in crude oil; they have poor solubility and can only dissolve in organic solvents such as petroleum ether, benzene, chloroform, ether, and carbon tetrachloride. They can also be adsorbed by silica gel. Oil with a lower density generally contains 4–5% gums, while heavier oil can have a gum content of 20% or even higher. The percentage of gums contained in crude oil is called the gum content. Asphaltene is a brittle substance ranging in color from dark brown to black; it is a high-molecular-weight polycyclic organic compound containing various elements such as carbon, hydrogen, oxygen, nitrogen, and sulfur. Its molecular weight is many times higher than that of resin, and it is insoluble in petroleum ether
Oil is mainly hydrocarbons. The molecular structure of petroleum: It is composed of a mixture of different hydrocarbons. The main chemical elements that make up petroleum are carbon (83% – 87%) and hydrogen (11% – 14%); the remaining elements include sulfur (0.06% – 0.8%), nitrogen (0.02% – 1.7%), oxygen (0.08% – 1.82%), as well as trace amounts of metal elements such as nickel, vanadium, iron, and antimony. Hydrocarbons, formed by the combination of carbon and hydrogen, constitute the main component of oil, accounting for approximately 95% to 99%. These various hydrocarbons are classified according to their structure into alkanes, cycloalkanes, and aromatic hydrocarbons.
Compounds composed of carbon and hydrogen in petroleum have a complex composition that varies depending on the source. Based on their structure, they are further divided into alkanes (including straight-chain and branched alkanes), cycloalkanes (mostly alkylcyclopentanes and alkylcyclohexanes), and aromatic hydrocarbons (mostly alkylbenzenes); generally, petroleum does not contain olefins. The sulfur-containing compounds in petroleum mainly include thiol (RSH), thioether (RSR), disulfide (RSSR), and thiophene, etc. Some petroleum processing products also contain hydrogen sulfide (H2S). The oxygen-containing compounds in petroleum mainly include naphthenic acids and phenols (primarily phenol), in addition to small amounts of fatty acids. Cycloalkanoic acids are carboxylic acids containing 11 to 30 carbon atoms, with one or more fused alicyclic rings in their structure; the carboxyl group can be located on the alicyclic ring or on a side chain. For example, in oil refining, naphthenic acids and phenols are often referred to as petroleum acids. The nitrogen-containing compounds in petroleum mainly include pyridine, pyrrole, quinoline, and amines (RNH2), etc. Since pyrrole oxidizes easily in air, its color gradually darkens, which is similar to the darkening of gasoline over time. The chemical composition of oil is not fixed; it varies depending on the source. Based on the different hydrocarbon components, petroleum is generally classified into several major categories such as alkanic-based petroleum, naphthenic-based petroleum, mixed-based petroleum, and aromatic-based petroleum. However, many oil-producing countries **often use different classifications based on their own resource conditions.