Degussa Aktiengesellschaft

Deutsche Gold- Und Silber-scheideanstalt Vormals Roessler

Horst Kruger

Gerhard Morlock

Heinz Haschke

Helmut Junkermann

Gerhard Arnold

Gerhard Hebbel

Wilhelm Berndt

Hans U Suss

Ursula Schwartzkopff

Sigrid Anspach

Peter Kuzel

Hans Jelitto

Hans-Ulrich Suss

A process for the delignification and bleaching of cellulose with oxygen and hydrogen peroxide, in which in a given case the delignification is carried out with oxygen in the presence of MgO, and the cellulose subsequently is bleached simultaneously with hydrogen peroxide and oxygen at a pH&lt;5.

Process for the delignification and acid bleaching of cellulose with

Cellulose is bleached by means of an organic peracid in the acid region and subsequently by means of peroxide in the alkaline region. As peracid there is employed an acid which is produced from the corresponding carboxylic acid by reaction with hydrogen peroxide in the presence of a mineral acid. The peroxide bleaching step which follows the peracid bleaching step is carried out after there is added the necessary amount of aqueous alkali solution for carrying out the peroxide bleaching step of the pulp without intermediate washing of the cellulose. A further addition of peroxide is not carried out.

Process for bleaching cellulose with organic peracid

Waste water containing phenol, phenol derivatives or phenol plus formaldehyde is purified by treating the waste water with hydrogen peroxide and either iron, copper or the complex salt sodium iron (III) ethylenediamine tetraacetate.

Process for the detoxification of waste water containing phenol, phenol

Process for dispersing solid, organic or inorganic colorant particles or mixtures thereof in a system comprised mainly of water by mixing into the aqueous system about 0.05 to 10% by weight of at least one dispersing agent comprising a polymer derived from specified units containing carboxyl, carboxylate, carbonyl and/or hydroxyl groups. A dispersing agent and an aqueous dispersion are provided. The process is particularly useful for dispersing pigments in aqueous systems.

Process for dispersing undissolved solid, organic or inorganic colorant

A process for decreasing the hygroscopicity of a polycarboxylate, said process comprising preparing a melt of a composition having a melting point of about 40.degree. - 120.degree. C, said composition giving an acid or neutral pH in an aqueous solution or suspension, said composition being less hygroscopic than said polycarboxylate, said composition capable of being free flowing under equilibrium conditions at about 30.degree. C and in an air atmosphere of at least about 40% relative humidity; heating said melt in a mixer to a temperature of up to about 140.degree. C; gradually adding said polycarboxylate as a powder to said melt while mixing said melt; wherein said composition comprises at least about 3 and at most about 40% by weight of the mixture resulting after all polycarboxylate has been added to said melt.

Process for decreasing the hygroscopicity of polycarboxylates

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Darmstadt, Germany

Horst Kruger