Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An improved process for producing adipic acid from the acidic wash waters which arise in the process for oxidizing cyclohexane with air, by treatment with nitric acid at from 10.degree. to 50.degree. C., with removal of the heat of reaction by external cooling, wherein the reaction mixture is led, at a flow velocity of at least 2.0 m/sec, as a thin layer spirally in counter-current to the coolant, under conditions which do not perturb the flow of the reaction mixture.

Abstract: Aromatic and araliphatic aldehydes are prepared by oxidizing corresponding alcohols with oxygen in the presence of a silver catalyst of a defined particle size, and under defined temperature conditions. The products are starting materials for the preparation of dyes, pesticides, plastics and scents.

Abstract: Continuous production of lactams by rearrangement of cycloalkanone oximes at from 210.degree. to 450.degree.C in contact with a supported catalyst in a fluidized bed wherein from 0.01 to 1 kg of steam is introduced above the fluidized bed for each kg of cycloalkanone oxime supplied. Lactams are starting materials for the production of synthetic polyamides suitable for fibers.