Reference

Opaque organic pigments

Opaque organic pigments. Brandt, Horst; Hoernle, Reinhold; Wolf, Karl Heinz; Moells, Hans H. (Bayer A.-G., Ger.). Ger. Offen. DE 2521249 2 Dec 1976, 9 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C09B067-00. APPLICATION: DE 75-2521249 13 May 1975. DOCUMENT TYPE: Patent CA Section: 42 (Coatings, Inks, and Related Products) Removing H2O in the press cake of azo dyes by azeotropic distn. with propionitrile (I) [107-12-0] or C6H6 [71-43-2] and drying in vacuo gave pigments facilitating a transparent color impression and sufficient rheol. properties in binders. Thus, a mixt. of 80 g H2O-contg. press cake of 4,4'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[2,4-dihydro-5-met hyl-2-(4-methylphenyl)-3H-pyrazol-3-one] (II) [15793-73-4] and 200 g I was distd. in thin layer evaporator at 82.2.degree. 107-12-0 and 6535-46-2 are just another two chemicals used in this study., and dried to give II pigment with improved covering power and fastness to light. .

Disazo pigments with improved industrial use properties

Disazo pigments with improved industrial use properties. Heckl, Leonhard; Liedek, Egon; Ruff, Wolfgang (BASF Farben und Fasern A.-G., USSR). Ger. Offen. DE 2629076 5 Jan 1978, 7 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: C09B035-18. APPLICATION: DE 76-2629076 29 Jun 1976. DOCUMENT TYPE: Patent CA Section: 40 (Dyes, Fluorescent Whitening Agents, and Photosensitizers) C.I. Pigment Orange 34 (I) [15793-73-4] prepd. by adding 1 mol tetrazotized 3,3'-dichlorobenzidine [91-94-1] to a suspension of 2 mol 1-(p-tolyl)-3-methyl-5-pyrazolone (II) [86-92-0] in H2O, holding at 30°, boiling, filtering, and neutralizing is equiv. in properties to I prepd. by using a soln. of II in aq. NaOH.