Abstract: A process for whitening paper in a size press includes contacting a cellulose sheet with a size press liquor that contains a surface size and a particular whitener containing sulfonate groups and cations, M, wherein at least 10% of all cations M have the formula in which R5 to R7, independently of one another, denote hydrogen, a C1-C4-alkyl radical or an optionally further substituted C2-C4-hydroxyalkyl radical, and R8 denotes an optionally further substituted C2-C4-hydroxyalkyl radical. The process provides superior paper whitening compared to a corresponding process in which the whitener cations are all sodium or potassium ions.

Abstract: The invention relates to compounds of formula (I) wherein R1, R2, R3 and R4 independently represent OR3 or NR6R7; R5, R6 and R7 independently represent hydrogen, substituted or unsubstituted alkyl, especially C1-C4 alkyl, or substituted or unsubstituted aryl, especially C6-C10 aryl; R6, R7 can also form an aliphatic or aromatic ring, together with the N atom to which they are bonded and optionally other heteroatoms; M represents hydrogen, an equivalent of a monovalent or bivalent metal ion, especially from the group of alkali metals or alkaline earth metals, or of an optionally organically substituted ammonium ion; and B1 represents a bivalent binding link.

Abstract: The use of optical brighteners of the formula (II): in which Y denotes a radical of the formula and the other substituents have the meaning stated in the description, for brightening aqueous coating slips comprising at least one latex binder and at least one synthetic co-binder differing therefrom.

Abstract: Process for whitening paper in the size press, characterized in that the size press liquor contains a whitener of the formula I in which X, independently of one another, denote a radical of the formula and R1 represents C1-C6-alkyl and R2 represents H, or R1 represents H and R2 represents C1-C6-alkyl, and, independently thereof, R3 represents H, methyl, ethyl, CH2CH2OH or CH2CH2OCH3, R1? represents C1-C6-alkyl and R2? represents H, or R1? represents H and R2? represents C1-C6-alkyl, and, independently thereof, R3? represents H, methyl, ethyl, CH2CH2OH or CH2CH2OCH3 and R4 represents C1-C4-alkyl and M denotes H, one equivalent of an inorganic cation, in particular Li, Na, K, Ca, Mg or ammonium, or a substituted ammonium of the formula II in which R5 to R7, independently of one another, denote hydrogen, a C1-C4-alkyl radical or an optionally further substituted C2-C4-hydroxyalkyl radical, and R8 denotes an optionally further substituted C2-C4-hydroxyalkyl radical, at least 10 mol % of

Abstract: The use of optical brighteners of the formula (II): 1

Abstract: The invention relates to a method of optically brightening natural or synthetic materials with aqueous brightener preparations containing

Abstract: Preparations of solids comprising a) at least one particulate solid and b) a water-dispersible graft copolymer built up from at least one hydrophobic, ethylenically unsaturated monomer, optionally one or more ethylenically unsaturated hydrophilic monomers, and at least one natural protective colloid or protective colloid obtained from a natural protective colloid by derivatization or thermal, enzymatic, oxidative, hydrolytic or bacteriological degradation having an average molar mass of Mn>500 g/mol.

Abstract: Dyestuffs of the general formula ##STR1## wherein R.sub.1 denotes alkyl, alkenyl, aralkyl or cycloalkyl,R.sub.2 denotes hydrogen, alkyl, alkenyl, aryl, aralkyl or cycloalkyl, or alkylene bonded to the ring a,R.sub.3 denotes hydrogen or one or more non-ionic substituents customary in dyestuff chemistry andX.sup.- denotes an anion,wherein an aromatic or cycloaliphatic ring can be fused to the ring a, and wherein the radicals mentioned can carry non-ionic substituents customary in dyestuff chemistry, are obtained, if 4-methylpyridine is treated with a quaternizing agent of the formulaR.sub.1 --X (II)whereinX denotes a group which can be split off in the form of the anion X.sup.-,within a temperature range from -20.degree. C. up to the boiling point of the system, the resulting reaction product is reacted with a base and a nitrite of the formulaR--O--N.dbd.O (III)whereinR denotes an organic radical,within a temperature range from -20.degree. C. to +60.degree. C.

Abstract: To prepare dyestuffs of the general formula ##STR1## in which R.sup.1 and R.sup.2 represent methyl or ethyl,n represents 0 or 1,B represents the divalent radical of a 5-membered or 6-membered heterocyclic ring system andX.sup.- represents an anion,and whereinthe ring a can be substituted by C.sub.1 - to C.sub.4 -alkyl radicals, C.sub.1 - to C.sub.4 -alkoxy radicals or halogen,compounds of the formula ##STR2## wherein R.sup.1, B and n have the meaning indicated above,m represents 0 or 1 andthe ring a can be substituted by C.sub.1 - to C.sub.4 -alkyl, C.sub.1 - to C.sub.4 -alkoxy or halogen,or of the formula ##STR3## in which B and R.sup.1 have the abovementioned meaning and the ring a can be substituted by C.sub.1 - to C.sub.4 -alkyl, C.sub.1 - to C.sub.4 -alkoxy or halogen,are reacted with arylsulphonic acid esters of the formula ##STR4## wherein R represents hydrogen, C.sub.1 - to C.sub.4 -alkyl or halogen andR.sup.

Abstract: Pyridine-4-aldehyde phenylhydrazones are prepared by catalytic hydrogenation of 4-cyano-pyridine under normal pressure or almost normal pressure in the presence of phenylhydrazine or nuclear-substitution products thereof, in an aqueous medium in the absence of organic solvents, at a pH value between 9 and 12, preferably between 9.5 and 11, and in a temperature range from 0.degree. to 60.degree. C.