WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
29.30 - Organo-sulphur compounds. 2930.20 2930.30 2930.40 2930.50 2930.90 - Thiocarbamates and dithiocarbamates - Thiuram mono-, di- or tetrasulphides - Methionine - Captafol (ISO) and methamidophos (ISO) - Other This heading includes organo-sul hur compounds whose molecules have sulphur atom(s) directly linked to carbon atom(s) Pee Note 6 to this Chapter). It includes compounds whose molecules contain, in addition to sulphur atom(s), other non-metal or metal atom(s) directly linked to carbon atom(s). (A) DITHIOCARBONATES (XANTHATES) These are diesters or 7alts of monoesters of dithiocarbonic acif and correspond to the general formula (ROC(S)SRR ) in which R is an organic radical and R is a metal (sodium, potassium, etc.) or an organic radical. (1) Sodium ethyldithiocarbonate (ethylxanthate). Amorphous; used to prepare synthetic indigo, and in the flotation of ores. (2) Potassium eth ldithiocarbonate (ethylxanthate). Oily, yellowish crystals; used as a flotation agent or lead and zinc ores, and as an antiparasitic and anticryptogamic agent. ? (3) Methyl-, butyl-, pentyl- and benzyldithiocarbonates (xanthates). (B) THIOCARBAMATES, DITHIOCARBAMATES AND THIURAM SULPHlDES (1) Thiocarbamates include the salts and esters of thiocarbmic acid (H2NCOSH or H2NCSOH) (which does not exist in the fkee state), whether or not hydrogen atoms of the NH, group are substituted with alkyl or aryl groups. (2) Dithiocarbamates include the salts and esters of dithiocarbamic acid, whether or not hydro en atoms of the NH2 group are substituted with alkyl or aryl oups. The metal salts of su stituted dithiocarbamic acids (e ., zinc dibutyldithiocar amate) are used as wlcanisation accelerators in the rubber i n g s t y . f, T (3) Thiuram mono-, di- or tetrasulphides. The alkyl substituted derivatives (e.g., tetraethylthiuram disulphide) are used as vulcanisation accelerators. (C) SULPHIDES (OR THIOETHERS) These may be regarded as ethers in which the oxygen atom is replaced by one of sulphur (RSR') ............ (ROR') ................................................................................................. sulphide ether (I) Methionine. White platelets or powder. An amino acid. Essential component in human nutrition, not syntheslsed by the body. (2) Dimethyl sulphide, diphenyl sulphide. Colourless liquids with a very disagreeable odour. (3) Thiodiglycol or bis(2-hydroxyethy1)sulphide; a liquid used as a solvent for dyes in textile printing. (4) Thioaniline or 4,4'-diaminodiphenyl sulphide. @) THIOAMIDES I (1) Thiourea H2NCSW) is the diamide of thiocarbonic acid and is thus the sulphur analogue o urea. Lustrous, white crystals. Used in photogra hy, as an auxiliary in dyeing, and for preparing intermediate compounds in the dyestuff an pharmaceutical industnes. ! (2) Thiocarbanilide (diphenylthiourea). Colourless, crystalline tablets or amorphous white powder. Used for preparing intermediate compounds in the dyestuffs industry (sulphur dyes, indigo) and synthetic pharmaceutical products; also as an accelerator in the vulcanisation of rubber, and for the flotation of ores. (3) Di-o-tolylthiourea. White powder, insoluble in water; used as an accelerator in the vulcanisation of rubber. (E) THIOLS (MERCAPTANS) These sulphur corn ounds correspond to alcohols or phenols in which the oxygen atoms have been replaced by su phur atoms. (ROW ............................................................................................................... (RSH) mercaptan alcohol or phenol (1) Thioalcohoqlike a l c o b o l s ~ a ybe primary, secondary or tertiary, containing the groups (-CH2SH), (/CHSH) or (TCSH), respectively. They are generally colourless or yellowish liquids with a disagreeable odour. (a) Methanethiol (methyl mercaptan). (b) Ethanethiol (ethyl mercaptan). (c) Butanethiol (butyl mercaptan). (d) Pentanethiol (pentyl mercaptan). (2) Thiophenols. (a) Thiophenol (C6HSSH) (b) o-Mercaptobenzoic acid, sometimes described as thiosalicylic acid. (F) THIOALDEHYDES General formula (RCSH). (G) THIOKETONES General formula (RcsR'). (H) THIOACIDS General formula (RCOSH or RCSOH and also RCSSH). An exam le is dithiosalicylic acid (HOC6H4CSSH),but this name is often applied to the compoun di(o-carboxyphenyl) disulphide. i! (IJ) SULPHINIC ACIDS, SULPHOXIDES AND SULPHONES These have the general formulae (RSOzH), (RSOR') and (RSO~R'),respectively. An example is sulphonal, colourless crystals, used in medicine. (K) ISOTHIOCYANATES General formula (RN=CS). They may be regarded as the "esters" of isothiocyanic acid. They include ethyl isothiocyanate; phenyl isothiocyanate; ally1 isothiocyanate (or arhficial mustard oil). -
1.- Except where the context otherwise requires, the headings of this Chapter apply only to : (a) Separate chemically defined organic compounds, whether or not containing impurities; (b) Mixtures of two or more isomers of the same organic compound (whether or not containing impurities), except mixtures of acyclic hydrocarbon isomers (other than stereoisomers), whether or not saturated (Chapter 27); (c) The products of headings 29.36 to 29.39 or the sugar ethers, sugar acetals and sugar esters, and their salts, of heading 29.40, or the products of heading 29.41, whether or not chemically defined; (d) The products mentioned in (a), (b) or (c) above dissolved in water; (e) The products mentioned in (a), (b) or (c) above dissolved in other solvents provided that the solution constitutes a normal and necessary method of putting up these products adopted solely for reasons of safety or for transport and that the solvent does not render the product particularly suitable for specific use rather than for general use; (f) The products mentioned in (a), (b), (c), (d) or (e) above with an added stabiliser (including an anti- caking agent) necessary for their preservation or transport; (g) The products mentioned in (a), (b), (c), (d), (e) or (f) above with an added anti-dusting agent or a colouring or odoriferous substance or an emetic added to facilitate their identification or for safety reasons, provided that the additions do not render the product particularly suitable for specific use rather than for general use; (h) The following products, diluted to standard strengths, for the production of azo dyes : diazonium salts, couplers used for these salts and diazotisable amines and their salts. 2.- This Chapter does not cover : (a) Goods of heading 15.04 or crude glycerol of heading 15.20; (b) Ethyl alcohol (heading 22.07 or 22.08); (c) Methane or propane (heading 27.11); (d) The compounds of carbon mentioned in Note 2 to Chapter 28; (e) Immunological products of heading 30.02; (f) Urea (heading 31.02 or 31.05); (g) Colouring matter of vegetable or animal origin (heading 32.03), synthetic organic colouring matter, synthetic organic products of a kind used as fluorescent brightening agents or as luminophores (heading 32.04) or dyes or other colouring matter put up in forms or packings for retail sale (heading 32.12); (h) Enzymes (heading 35.07); (ij) Metaldehyde, hexamethylenetetramine or similar substances, put up in forms (for example, tablets, sticks or similar forms) for use as fuels, or liquid or liquefied-gas fuels in containers of a kind used for filling or refilling cigarette or similar lighters and of a capacity not exceeding 300 cm3 (heading 36.06); (k) Products put up as charges for fire-extinguishers or put up in fire-extinguishing grenades, of heading 38.13; ink removers put up in packings for retail sale, of heading 38.24; or (l) Optical elements, for example, of ethylenediamine tartrate (heading 90.01). 3.- Goods which could be included in two or more of the headings of this Chapter are to be classified in that one of those headings which occurs last in numerical order. 4.- In headings 29.04 to 29.06, 29.08 to 29.11 and 29.13 to 29.20, any reference to halogenated, sulphonated, nitrated or nitrosated derivatives includes a reference to compound derivatives, such as sulphohalogenated, nitrohalogenated, nitrosulphonated or nitrosulphohalogenated derivatives. Nitro or nitroso groups are not to be taken as “nitrogen-functions” for the purposes of heading 29.29. For the purposes of headings 29.11, 29.12, 29.14, 29.18 and 29.22, “oxygen function”, the characteristic organic oxygen-containing group of those respective headings, is restricted to the oxygen-functions referred to in headings 29.05 to 29.20.