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A sulfonic acid has the general formula RS(=O)2–OH, where R is an organic radical. |
Methanesulfonic acid (or mesylic acid, CH3SO3H) |
Ethanesulfonic acid (or esylic acid, CH3CH2SO3H) |
Benzenesulfonic acid (or besylic acid, C6H5SO3H) |
p-Toluenesulfonic acid (or tosylic acid, CH3C6H4SO3H) |
Trifluoromethanesulfonic acid (or triflic acid, CF3SO3H) |
Polystyrene sulfonic acid (sulfonated polystyrene, [CH2CH(C6H4)SO3H]n) |
Carboxylic acids |
A carboxylic acid has the general formula R-C(O)OH, where R is an organic radical. The carboxyl group -C(O)OH contains a carbonyl group, C=O, and a hydroxyl group, O-H. |
Acetic acid (CH3COOH) |
Citric acid (C6H8O7) |
Formic acid (HCOOH) |
Gluconic acid HOCH2-(CHOH)4-COOH |
Lactic acid (CH3-CHOH-COOH) |
Oxalic acid (HOOC-COOH) |
Tartaric acid (HOOC-CHOH-CHOH-COOH) |
Halogenated carboxylic acids |
Halogenation at alpha position increases acid strength, so that the following acids are all stronger than acetic acid. |
Fluoroacetic acid |
Trifluoroacetic acid |
Chloroacetic acid |
Dichloroacetic acid |
Trichloroacetic acid |
Vinylogous carboxylic acids |
Normal carboxylic acids are the direct union of a carbonyl group and a hydroxyl group. In vinylogous carboxylic acids, a carbon-carbon double bond separates the carbonyl and hydroxyl groups. |
Ascorbic acid |
Nucleic acids |
Deoxyribonucleic acid (DNA) |
Ribonucleic acid (RNA) |
References |
Listing of strengths of common acids and bases |
External links |
Curtipot: Acid–Base equilibria diagrams, pH calculation and titration curves simulation and analysis – freeware |
Acid–base chemistry Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient ... |
The primary use (70%) of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other main uses are for bituminous waterproofing products, including production of roofing felt and for sealing flat roofs. |
In material sciences and engineering, the terms "asphalt" and "bitumen" are often used interchangeably to mean both natural and manufactured forms of the substance, although there is regional variation as to which term is most common. Worldwide, geologists tend to favor the term "bitumen" for the naturally occurring ma... |
Naturally occurring asphalt is sometimes specified by the term "crude bitumen". Its viscosity is similar to that of cold molasses while the material obtained from the fractional distillation of crude oil boiling at is sometimes referred to as "refined bitumen". The Canadian province of Alberta has most of the world's ... |
Asphalt properties change with temperature, which means that there is a specific range where viscosity permits adequate compaction by providing lubrication between particles during the compaction process. Low temperature prevents aggregate particles from moving, and the required density is not possible to achieve. Comp... |
Terminology |
Etymology |
The word "asphalt" is derived from the late Middle English, in turn from French asphalte, based on Late Latin asphalton, asphaltum, which is the latinisation of the Greek (ásphaltos, ásphalton), a word meaning "asphalt/bitumen/pitch", which perhaps derives from , "not, without", i.e. the alpha privative, and (sphalle... |
The Latin source of the word "bitumen" is claimed by some to be originally gwitu-men (pertaining to pitch), and by others, pixtumens (exuding or bubbling pitch), which was subsequently shortened to bitumen, thence passing via French into English. From the same root is derived the Anglo-Saxon word cwidu (mastix), the Ge... |
Modern terminology |
In British English, "bitumen" is used instead of "asphalt". The word "asphalt" is instead used to refer to asphalt concrete, a mixture of construction aggregate and asphalt itself (also called "tarmac" in common parlance). Bitumen mixed with clay was usually called "asphaltum", but the term is less commonly used today. |
In Australian English, the word "asphalt" is used to describe a mix of construction aggregate. "Bitumen" refers to the liquid derived from the heavy-residues from crude oil distillation. |
In American English, "asphalt" is equivalent to the British "bitumen". However, "asphalt" is also commonly used as a shortened form of "asphalt concrete" (therefore equivalent to the British "asphalt" or "tarmac"). |
In Canadian English, the word "bitumen" is used to refer to the vast Canadian deposits of extremely heavy crude oil, while "asphalt" is used for the oil refinery product. Diluted bitumen (diluted with naphtha to make it flow in pipelines) is known as "dilbit" in the Canadian petroleum industry, while bitumen "upgraded"... |
"Bitumen" is still the preferred geological term for naturally occurring deposits of the solid or semi-solid form of petroleum. "Bituminous rock" is a form of sandstone impregnated with bitumen. The oil sands of Alberta, Canada are a similar material. |
Neither of the terms "asphalt" or "bitumen" should be confused with tar or coal tars. Tar is the thick liquid product of the dry distillation and pyrolysis of organic hydrocarbons primarily sourced from vegetation masses, whether fossilized as with coal, or freshly harvested. The majority of bitumen, on the other hand,... |
Composition |
Normal composition |
The components of asphalt include four main classes of compounds: |
Naphthene aromatics (naphthalene), consisting of partially hydrogenated polycyclic aromatic compounds |
Polar aromatics, consisting of high molecular weight phenols and carboxylic acids produced by partial oxidation of the material |
Saturated hydrocarbons; the percentage of saturated compounds in asphalt correlates with its softening point |
Asphaltenes, consisting of high molecular weight phenols and heterocyclic compounds |
The naphthene aromatics and polar aromatics are typically the majority components. Most natural bitumens also contain organosulfur compounds, resulting in an overall sulfur content of up to 4%. Nickel and vanadium are found at <10 parts per million, as is typical of some petroleum. |
The substance is soluble in carbon disulfide. It is commonly modelled as a colloid, with asphaltenes as the dispersed phase and maltenes as the continuous phase. "It is almost impossible to separate and identify all the different molecules of asphalt, because the number of molecules with different chemical structure is... |
Asphalt may be confused with coal tar, which is a visually similar black, thermoplastic material produced by the destructive distillation of coal. During the early and mid-20th century, when town gas was produced, coal tar was a readily available byproduct and extensively used as the binder for road aggregates. The add... |
Additives, mixtures and contaminants |
For economic and other reasons, asphalt is sometimes sold combined with other materials, often without being labeled as anything other than simply "asphalt". |
Of particular note is the use of re-refined engine oil bottoms – "REOB" or "REOBs"the residue of recycled automotive engine oil collected from the bottoms of re-refining vacuum distillation towers, in the manufacture of asphalt. REOB contains various elements and compounds found in recycled engine oil: additives to the... |
Occurrence |
The majority of asphalt used commercially is obtained from petroleum. Nonetheless, large amounts of asphalt occur in concentrated form in nature. Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae (diatoms) and other once-living things. These natural deposits of bitumen ha... |
Natural deposits of bitumen include lakes such as the Pitch Lake in Trinidad and Tobago and Lake Bermudez in Venezuela. Natural seeps occur in the La Brea Tar Pits and in the Dead Sea. |
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