Derwent Classification System: General Chemicals

Derwent Classification System: General Chemicals

Patents concerning the production, purification, use, detection, removal or phase changes, of non-polymeric chemical compounds, and apparatus or novel catalysts for producing them, are classified in Section E.

Exceptions to this are:

Compounds stated to be solely for use as a pharmaceutical, veterinary medicament, fertiliser, herbicide or pesticide which are classified only in Sections B and/or C. However, where an additional use is stated, eg the compound is also a dyestuff intermediate, the patent is classified in Sections B and/or C and E.
Monomers taking part in a polymerisation reaction and starting materials for a chemical reaction are not classified in Section E, unless the patent is also concerned with the production or purification of the monomer/starting material.
Polymerisation catalysts are not normally classified in Section E, unless the novelty of the invention is the catalyst and it is a single compound.
Mixtures of compounds described as a cut in petrochemical process are normally classified in Section H only.
Highly complex non-stoichiometric compounds, eg those used as fluorescent materials are classified in Section L only, but simpler compounds are normally classified also in Section E. Growth of single crystals of pure elements or compounds eg Si, GaAs or BN is classified in Sections E and L.

Where necessary a patent is classified in Section E for the compound and other Section(s) for its use(s), etc. Typically, perfumes, flavourings and additives to foods and tobacco are normally classified in Sections D and E. Solvents and very common reagents such as water are not normally classified in Section E. For each compound, when more than one of the classifications below could be assigned, then the priority is E11 before E12 and E12 before E13.

E1	GENERAL ORGANIC
E11	Containing P and/or Si.
E12	Organometallics - ie containing other than H, C, N, O, S, halogens, Si and P.
E13	Heterocyclics.
E14	Aromatics - ie containing at least one benzene ring.
E15	Alicyclics.
E16	Aliphatics - containing N and/or halogen.
E17	Other aliphatics.
E18	General hydrocarbon mixtures.
E19	Other organic compounds general - organic compounds of unknown or indefinite structure; general mixtures of many types; organic reactions (eg nitration, resolution) when applied generally.
E2	DYESTUFFS
E21	Azo - including diazonium compounds.
E22	Anthracene - including those containing more than 3 rings.
E23	Heterocyclic.
E24	Other dyes, all precursors.
E3	GENERAL INORGANIC
E31	Compounds of V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Pa, V and subsequent actinides.
E32	Compounds of Ti, Zr, Hf, Cu, Ag, Au, Zn, Cd, Hg, Ga, In, Te, Ge, Sn, Pb, As, Sb, Bi.
E33	Compounds of Be, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ac, Al, lanthanides (Rare-earths), Th.
E34	Compounds of Li, Na, K, Rb, Cs, Fr.
E35	Ammonia, cyanogen and their compounds - including HCN and cyanamide, but not hydrazine.
E36	Non-metallic elements, semi-metals (Se, Te, B, Si) and their compounds (except for E35).
E37	Mixtures of many components; inorganic reactions and processes of general applicability.