Names | |||
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Preferred IUPAC name Benzenethiol [1] | |||
Other names
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Identifiers | |||
3D model (JSmol) | |||
506523 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.003.306 | ||
EC Number |
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PubChem CID | |||
RTECS number |
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UNII | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
C6H6S | |||
Molar mass | 110.17 g·mol−1 | ||
Appearance | Colorless liquid | ||
Odor | Unpleasant, pungent | ||
Density | 1.0766 g/mL | ||
Melting point | −15 °C (5 °F; 258 K) | ||
Boiling point | 169 °C (336 °F; 442 K) | ||
0.08% [2] | |||
Solubility | Most organic solvents; aqueous base | ||
Vapor pressure | 1 mmHg (18°C) [2] | ||
Acidity (pKa) | |||
-70.8·10−6 cm3/mol | |||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | Toxic | ||
GHS labelling: | |||
Danger | |||
H226, H300, H310, H314, H315, H330, H410 | |||
P210, P233, P240, P241, P242, P243, P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P301+P330+P331, P302+P350, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P320, P321, P322, P330, P332+P313, P361, P362, P363, P370+P378, P391, P403+P233, P403+P235, P405, P501 | |||
NFPA 704 (fire diamond) | |||
Flash point | 56 °C; 132 °F; 329 K [2] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible) | none [2] | ||
REL (Recommended) | C 0.1 ppm (0.5 mg/m3) [15-minute] [2] | ||
IDLH (Immediate danger) | N.D. [2] | ||
Related compounds | |||
Related thiols | 1,2-Benzenedithiol Benzenemethanethiol | ||
Related compounds | Phenol Benzeneselenol Diphenyl disulfide | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols . An exception is the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom.
Thiophenols also describes a class of compounds formally derived from thiophenol itself. All have a sulfhydryl group (-SH) covalently bonded to an aromatic ring. The organosulfur ligand in the medicine thiomersal is a thiophenol.
There are several methods of synthesis for thiophenol and related compounds, although thiophenol itself is usually purchased for laboratory operations. 2 methods are the reduction of benzenesulfonyl chloride with zinc [5] and the action of elemental sulfur on phenyl magnesium halide or phenyllithium followed by acidification.
Via the Newman–Kwart rearrangement, phenols (1) can be converted to the thiophenols (5) by conversion to the O-aryl dialkylthiocarbamates (3), followed by heating to give the isomeric S-aryl derivative (4). [6]
In the Leuckart thiophenol reaction, the starting material is an aniline through the diazonium salt (ArN2X) and the xanthate (ArS(C=S)OR). [7] [8] Alternatively, sodium sulfide and triazene can react in organic solutions and yield thiophenols. [9]
Thiophenol can be manufactured from chlorobenzene and hydrogen sulfide over alumina at 700 to 1,300 °F (371 to 704 °C). The disulfide is the primary byproduct. [10] The reaction medium is corrosive and requires ceramic or similar reactor lining. Aryl iodides and sulfur in certain conditions may also produce thiophenols. [11]
Thiophenols are used in the production of pharmaceuticals including of sulfonamides. The antifungal agents butoconazole and merthiolate are derivatives of thiophenols. [9]
Thiophenol has appreciably greater acidity than does phenol, as is shown by their pKa values (6.62 for thiophenol and 9.95 for phenol). A similar pattern is seen for H2S versus H2O, and all thiols versus the corresponding alcohols. Treatment of PhSH with strong base such as sodium hydroxide (NaOH) or sodium metal affords the salt sodium thiophenolate (PhSNa).
The thiophenolate is highly nucleophilic, which translates to a high rate of alkylation. [12] Thus, treatment of C6H5SH with methyl iodide in the presence of a base gives methyl phenyl sulfide, C6H5SCH3, a thioether often referred to as thioanisole. Such reactions are fairly irreversible. C6H5SH also adds to α,β-unsaturated carbonyls via Michael addition.
Thiophenols, especially in the presence of base are easily oxidized to diphenyl disulfide:
The disulfide can be reduced back the thiol using sodium borohydride followed by acidification. This redox reaction is also exploited in the use of C6H5SH as a source of H atoms.
Phenylsulfenyl chloride, a blood-red liquid (b.p. 41–42 °C, 1.5 mm Hg), can be prepared by the reaction of thiophenol with chlorine (Cl2). [13]
Metal cations form thiophenolates, some of which are polymeric. One example is "C6H5SCu," obtained by treating copper(I) chloride with thiophenol. [14]
The US National Institute for Occupational Safety and Health has established a recommended exposure limit at a ceiling of 0.1 ppm (0.5 mg m−3), and exposures not greater than 15 minutes. [15]
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula R−O−R′, where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−OH) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, C
6H
5OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule.
In biochemistry, a disulfide refers to a functional group with the structure R−S−S−R′. The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In biology, disulfide bridges formed between thiol groups in two cysteine residues are an important component of the secondary and tertiary structure of proteins. Persulfide usually refers to R−S−S−H compounds.
In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".
In organic chemistry, an organic sulfide or thioether is an organosulfur functional group with the connectivity R−S−R' as shown on right. Like many other sulfur-containing compounds, volatile sulfides have foul odors. A sulfide is similar to an ether except that it contains a sulfur atom in place of the oxygen. The grouping of oxygen and sulfur in the periodic table suggests that the chemical properties of ethers and sulfides are somewhat similar, though the extent to which this is true in practice varies depending on the application.
Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene. Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents.
Ethanethiol, commonly known as ethyl mercaptan, is an organosulfur compound with the formula CH3CH2SH. is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its structure parallels that of ethanol, but with sulfur in place of oxygen. The odor of EtSH is infamous. Ethanethiol is more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic in high concentrations. It occurs naturally as a minor component of petroleum, and may be added to otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful.
In organic chemistry, an aryl halide is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications.
In organic chemistry, sulfonic acid refers to a member of the class of organosulfur compounds with the general formula R−S(=O)2−OH, where R is an organic alkyl or aryl group and the S(=O)2(OH) group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group. A sulfonic acid can be thought of as sulfuric acid with one hydroxyl group replaced by an organic substituent. The parent compound is the parent sulfonic acid, HS(=O)2(OH), a tautomer of sulfurous acid, S(=O)(OH)2. Salts or esters of sulfonic acids are called sulfonates.
Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur is vital for life. Of the 20 common amino acids, two are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries.
In organic chemistry, a sulfoxide, also called a sulfoxide, is an organosulfur compound containing a sulfinyl functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. Examples of important sulfoxides are alliin, a precursor to the compound that gives freshly crushed garlic its aroma, and dimethyl sulfoxide (DMSO), a common solvent.
Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution. Aryl sulfonic acids are used as detergents, dye, and drugs.
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group [R−N+≡N]X− where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide.
Sodium sulfide is a chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides and commonly supplied as a crystalline mass, in flake form, or as a fused solid. They are water-soluble, giving strongly alkaline solutions. When exposed to moist air, Na2S and its hydrates emit hydrogen sulfide, an extremely toxic, flammable and corrosive gas which smells like rotten eggs.
Sulfur compounds are chemical compounds formed the element sulfur (S). Common oxidation states of sulfur range from −2 to +6. Sulfur forms stable compounds with all elements except the noble gases.
The Finkelstein reaction named after the German chemist Hans Finkelstein, is an SN2 reaction that involves the exchange of one halogen atom for another. It is an equilibrium reaction, but the reaction can be driven to completion by exploiting the differential solubility of halide salts, or by using a large excess of the halide salt.
In organic chemistry, alkyl nitrites are a group of organic compounds based upon the molecular structure R−O−N=O, where R represents an alkyl group. Formally they are alkyl esters of nitrous acid. They are distinct from nitro compounds.
Diphenyl disulfide is the chemical compound with the formula (C6H5S)2. This colorless crystalline material is often abbreviated Ph2S2. It is one of the more commonly encountered organic disulfides in organic synthesis. Minor contamination by thiophenol is responsible for the disagreeable odour associated with this compound.
In organosulfur chemistry, a sulfenyl chloride is a functional group with the connectivity R−S−Cl, where R is alkyl or aryl. Sulfenyl chlorides are reactive compounds that behave as sources of RS+. They are used in the formation of RS−N and RS−O bonds. According to IUPAC nomenclature they are named as alkyl thiohypochlorites, i.e. esters of thiohypochlorous acid.
In organic chemistry, thiocarboxylic acids or carbothioic acids are organosulfur compounds related to carboxylic acids by replacement of one of the oxygen atoms with a sulfur atom. Two tautomers are possible: a thione form and a thiol form. These are sometimes also referred to as "carbothioic O-acid" and "carbothioic S-acid" respectively. Of these the thiol form is most common.
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