PRODUCT IDENTIFICATION

H.S. CODE

TOXICITY

CLASSIFICATION

PHYSICAL AND CHEMICAL PROPERTIES

168 - 169 C

1.073

3.80

REFRACTIVE INDEX

50 C

APPLICATIONS

The first chemical contrast of thiols and sulfides with alcohols and ethers is acidity which is important in organic reactions. Thiols are stronger acids than relevant alcohols and phenols. Thiolate conjugate bases are easily formed, and are excellent nucleophiles in SN2 reactions of alkyl halides and tosylates. The nucleophilicity of sulfur is much greater than that of oxygen, resulting in a number of useful electrophilic substitution reaction that are rare by oxygen. For example, sulfides form (with alkyl halides) ternary sulfonium salts, in the same alkylattion of tert-amines quaternary ammonium salts, whereas ternary oxonium salts are prepared only under extream conditions. Without exception, sulfoxides, sulfinate salts and sulfite anion also alkylate on sulfur, despite of the partial negative formal charge on oxygen and partial positive charge on sulfur. The second character is the oxidation states of sulfur. Oxygen has only two oxidation states, whereas sulfur covers from –2 to +6 as follows:

• -2: Hydrogen Sulfide (H₂S), sulfides, sulfonium ions
• -1: disulfides
• 0: S elemental, sulfoxides, sulfenic acids
• +2: sulfones, sulfinic acids
• +4: sulfonic acids, sulfite esters
• +6: sulfate esters

One more sulfur compound's contrast with oxygen analog is in oxidation chemistry. Oxidation of sulfur compounds changes the oxidation state of sulfur rather than carbon, whereas, oxidation of  alcohols to aldehydes and ketones changes the oxidation state of carbon not oxygen. Thiol is oxidized to S-S single bond (disufide) which is stronger than O–O bond in peroxide. Disufide forms sulfenyl chlorides (with chlorine in mild condition) or sulfonic acids under harder condition. Oxidation of sulfides with hydrogen peroxide (or peracids) yields sulfoxides and then to sulfones. A certain sulfoxide compound such as dimethyl sulfoxide can be used as an effective oxygen source in the oxidation reaction of primary and secondary alcohols to aldehydes and ketones. DMSO easily is reduced to dimethyl sulfide and water is taken up by the electrophile. oxidation procedure is very mild and tolerates a variety of other functional groups, including those having oxidizable nitrogen and sulfur atoms.

Thiophenol is a compound of aromatic thiol which is structurally analogous to phenol; hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfhydryl group (-SH). This structure means that the oxygen atom hydroxyl group is replaced by a sulfur atom. Thiophenol is also called phenyl mercaptan. Thiophenol is a toxic, flammable clear liquid with a strong and disagreeable odor; boiling at 168 C. It is insoluble in water but soluble in alcohol and ether. Many chemical reactions of thiophenols are analogous to phenols. The substantial difference between sulfur and oxygen is that sulfur much more readily gets oxidized to higher oxidation states than oxygen. Sulfur in organic compounds is fairly stable in several oxidation states. Thiophenols can form thiophenolate anions by losing sulfhydryl H+ ions; used as reagents for the simple chemical preparation. The ring closure reaction of o-amino thiophenol produces benzothiazole, an important industrial product. Thiophenol itself is used as an antinematodal agent. Thiophenol class compounds have the skeleton of thiophenol.

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