Basf Aktiengesellschaft

Gunter Lehmann

Hans Diem

Christian Dudeck

Norbert Petri

Guenther Matthias

Albrecht Aicher

Werner Fliege

Karl-Heinz Ross

Bernd Meissner

Hans Haas

Wolfgang Muehlthaler

Heinrich Sperber

Fritz Brunnmueller

G&uuml;nter Scherr

Wolfgang Sauer

Norbert Biedermann

Walter Pitteroff

Franz Wolf

Stephan Weink&ouml;tz

Guenter Halbritter

Gunter Reuss

Hans Schreiber

Robert Sebastian

Ralph Lehnen

Oskar Hussey, Deceased

Herbert Libowitzky

Fiberplates made of polyamines or polyamine-containing aminoplast resins as binding agents

Formaldehyde is prepared by (a) passing a mixture of methanol and water with a concentration of between 50 and 90% by weight, based on the total weight of the two substances, of methanol into a packed column which possesses a packing having a total layer thickness of not less than 50 cm and a total surface area of not less than 0.5 cm.sup.2 per cm.sup.3 of packing, a liquid circulation of from 15 to 90 g/min per g/min of methanol fed to the column, and a concentration of from 10 to 45% by weight of methanol in the recycle liquid, the temperature at the point of entry of the recycle liquid in the column being from 50.degree. to 86.degree. C. and the bottom temperature being 10.degree.-25.degree. C. lower than this, i.e. from 40.degree. to 70.degree. C., (b) separating off methanol and water from the column by stripping with air, an inert gas and/or exit gas, the throughput being from 0.5 to 3 tonnes of methanol and water per hour per m.sup.2 of column cross-section, (c) converting the gaseous mixture of methanol, water, air, inert gas and/or exit gas at a space velocity of from 0.5 to 3 tonnes of methanol per m.sup.2 of catalyst bed cross-section per hour, in the presence of a silver catalyst at from 550.degree. to 750.degree. C. and (d) finally, cooling and absorbing the hot reaction gases, and using the resulting heat of absorption and, if desired, the heat of reaction and/or the heat of condensation partially or completely for heating the recycle liquid, methanol containing impurities being used if desired and, after the stages (a) and (b) and before the stages (c) and (d), the measures of a stage (e) being carried out, wherein the gaseous mixture formed is passed through two layers of wire filter having a wire diameter of from 0.1 to 0.5 mm and a free layer volume of from 90 to 99.5 vol. %, based on the total volume of one wire layer, at a flow rate of from 7 to 13 m/sec in the first layer, and from 1 to 4 m/sec in the second layer. The formaldehyde obtainable by the process of the invention is a disinfectant, tanning agent, reducing agent and a useful starting material for the preparation of synthetic resins, adhesives and plastics.

Preparation of formaldehyde

Glyoxal is prepared by oxidizing glycol in the presence of a silver catalyst of a defined particle size and under defined conditions of temperature, residence time and inert gas concentration. The glyoxal obtainable by the process of the invention may be used in wrinkle-resist finishing, as an assistant for increasing the tensile strength and resilience of fibrous materials, a tanning agent, a hardener in the photographic industry, and a starting material for the manufacture of synthetic resins, textile auxiliaries, for example to prevent shrinkage after washing, paper additives, for example for increasing the wet strength, and plastics.

Preparation of glyoxal

Diketones are prepared by oxidizing glycols in the presence of a silver catalyst and/or copper catalyst of a specific particle size, under specific temperature conditions and with a specific composition of the catalyst. The end products are starting materials for the preparation of dyes, drugs, plastics, scents, wrinkle-resist finishes and assistants for increasing the tear strength and resilience of fibrous materials, hardeners for use in the photographic industry, textile assistants for preventing shrinkage after washing, and paper assistants.

Preparation of diketones

Aliphatic hydroxycarbonyl compounds etherified with aliphatic groups are prepared by oxidizing hydroxyalcohols in the presence of a metal catalyst which consists of one or more layers, each of a particular weight and each containing particles of a particular size, the catalyst bed also having a particular total thickness, and the catalyst components used being silver and copper, with or without added copper/tin/phosphorus or silver alone. The etherified hydroxyaldehydes and hydroxyketones obtainable by the process of the invention are valuable starting materials for the preparation of dyes, pesticides, plastics and scents.

Manufacture of aliphatic hydroxycarbonyl compounds etherified with

Alkyl pyruvates are prepared by oxidizing alkyl lactates in the presence of a silver catalyst of a defined particle size, at from 450.degree. to 700.degree. C. The products are starting materials for the preparation of drugs, synthetic resins and plastics.

Preparation of alkyl pyruvates

Formaldehyde is manufactured by oxidative dehydrogenation of methanol in the presence of a silver catalyst and of certain amounts of steam and formaldehyde, some formaldehyde and a part of the water being withdrawn from the reaction mixture and recycled. The formaldehyde manufactured by the process may be used as a disinfectant, tanning agent, reducing agent and starting material for the manufacture of synthetic resin, adhesives and plastics.

Manufacture of concentrated aqueous solutions of formaldehyde

Formaldehyde is prepared by oxidative dehydrogenation of methanol in the presence of a silver catalyst, specific amounts of steam and specific amounts of an off-gas, of a specific composition, taken from the manufacture of formaldehyde. The reaction is started at a lower throughput of methanol and at a lower temperature. The formaldehyde obtainable by the process is a disinfectant, tanning agent and reducing agent, and a starting material for the manufacture of synthetic resins, adhesives and plastics.

Manufacture of formaldehyde

The production of formaldehyde by oxidizing dehydrogenation of methanol in the presence of a silver catalyst which consists of three or more layers each of specific weight and particles of specific particle size and having a specific total layer thickness. Formaldehyde prepared according to the process of the invention is a disinfectant, tanning agent, reducing agent and valuable starting material for the production of synthetic resins, adhesives and plastics.

Production of formaldehyde

Stabilized, aqueous formaldehyde solutions and a process for their manufacture by addition of isophthalobis-guanamine and/or terephthalo-bis-guanamine. The formaldehyde solution of the invention is used as a disinfectant, tanning agent or reducing agent, and as a starting material for the manufacture of synthetic resins, adhesives and plastics.

Stabilized aqueous formaldehyde solutions and process for their

Manufacture of formaldehyde by oxidative dehydrogenation of methanol in the presence of a silver catalyst, wherein methanol and water are evaporated in the presence of air in a plate column containing a number of double plates each consisting of a sieve plate and a lower plate having the form of a shallow bowl and inclined at a specific angle to the horizontal, the resulting vaporous mixture then being reacted. The formaldehyde which may be produced by the process of the invention is a disinfectant, tanning agent, reducing agent and a valuable starting material for the manufacture of synthetic resins, adhesives and plastics.

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Ludwigshafen, Germany

Gunter Lehmann