Abstract: A photoconductive layer sensitized by a compound of the general formula: ##STR1## in which: R.sup.1 and R.sup.2 independently represent a hydrogen atom, an alkyl or substituted alkyl group, an aryl or substituted aryl group, an aralkyl or substituted aralkyl group, a cycloaliphatic or substituted cycloaliphatic group or a heterocyclic or substituted heterocyclic group providing R.sup.1 and R.sup.2 do not both represent cyclic groups of aromatic nature, or R.sup.1 and R.sup.2 together may represent the necessary atoms to complete a non-aromatic heterocyclic ring,R.sup.3, R.sup.4, R.sup.5 and R.sup.6 independently represent a hydrogen atom or any substituent providing the sum of their .sigma..sub.p constants has a value of less than +0.5, or R.sup.3 and R.sup.4 and/or R.sup.5 and R.sup.6 may represent the necessary atoms to complete an alicyclic or aromatic ring, R.sup.3 and R.sup.2 and/or R.sup.1 and R.sup.6 may represent the necessary atoms to complete a non-aromatic heterocyclic ring,R.sup.7 and R.sup.

Abstract: A composite sorptive material in the form of a self-supporting, fluid-permeable sheet of fibrous material having distributed throughout a powdered sorbent material. The sheets provide a simple and convenient way of handling and using powdered sorbent materials. Suitable powdered sorbent materials include activated charcoal and powdered sorbent foam which has been prepared by the pyrolysis of an aromatic nitrogen-containing compound.

Abstract: A black sorbent thermoset foam which has been prepared by the pyrolysis of a composition comprising at least one Lewis acid metallic salt and at least one aromatic nitrogen-containing compound having the general formula:X -- Ar -- Yin which Ar represents an aromatic nucleus on which X and Y are substituents directly attached to the nucleus, X represents a substituent having a negative Hammett sigma constant and attached to the aromatic nucleus by a nitrogen, oxygen or sulphur atom, and Y represents a substituent having a positive Hammett sigma constant and attached to the aromatic nucleus by a nitrogen atom, and substituents X and/or Y optionally forming part of a ring fused onto the aromatic nucleus,Is an effective sorbtive substance for polar molecules and materials.