Translation of "Selenic acid" in German

A large number of inorganic substances have been used to activate the hydrogen peroxide, such as, for example, anhydrous hydrofluoric acid (Chemical Abstracts, volume 47 (1953), page 8,012) or selenic acid (Tetrahedron Letters, volume 13, (1959) page 1).

Preferred heteropoly acids are poly acids of molybdenum or tungsten with phosphoric acid, telluric acid, selenic acid, arsenic acid, silicic acid or, in particular, with phosphoric acid.

Preferred heteropoly acids are heteropoly acids of molybdenum or tungsten with phosphoric acid, telluric acid, selenic acid, arsenic acid, or silicic acid, preferably with phosphoric acid.

The selenate must therefore next be precipitated with a solution of a barium salt and subsequently, the resulting alkali metal selenate must be converted with a sulfuric acid to selenic acid and barium sulfate, which must then be separated.

Advantageous co-catalysts according to the invention are selenium and/or tellurium as the element or as a compound, e.g., selenium dioxide, selenous acid, selenic acid, tellurium dioxide, tellurium trioxide, tellurous acid or o-telluric acid.

The Se powders employed according to the invention may be brought to the required fineness by grinding and sorting of commercial powders; or they may be produced by reduction of selenic acid with sulfur dioxide and may be brought into the hexagonally crystallized form required for semiconductors by heat treatment.

The method according to claim 1, wherein Se is employed as the third alloy component to be embedded, and the Se is produced by the reduction of selenic acid with sulfur dioxide.

Preferred heteropoly acids are heteropoly acids of molybdenum or tungsten with phosphoric acid, telluric acid, selenic acid, arsenic acid, silicic acid, especially phosphoric acid.

Selenium can be added to the catalyst in the course of the preparation of the latter or to the ready-prepared catalyst in the form of a suitable compound such as selenium dioxide, selenous acid or selenic acid, which is reduced to selenium in the course of the reduction.

Preferably, the oxygen containing selenium compound is selected from salts of selenious acid (selenites), salts of selenic acid (selenates) and/or their hydrates, selenium dioxide (SeO 2), selenium trioxide (SeO 3) and mixtures thereof.

In a further particularly preferable embodiment of the disclosure the salt of the selenic acid is sodium selenate Na 2 SeO 4 and/or its hydrates.

In preferable embodiments of the present disclosure instead of the salt of selenious acid or instead of the salt of selenic acid the respective anhydride is used as a refining agent.

In further preferable embodiments as refining agents the salts of selenious acid or selenic acid are used in combination with the anhydrides of both acids.

Preferably, the selenium compound is selected from salts of selenious acid (selenites), salts of selenic acid (selenates) and/or their hydrates, selenium dioxide (SeO 2), selenium trioxide (SeO 3) and mixtures thereof.

Preferred heteropolyacids are heteropolyacids of molybdenum or tungsten with phosphoric acid, telluric acid, selenic acid, arsenic acid, silicic acid, in particular with phosphoric acid.

Selenium is liberated from selenous acid by SO2 addition:

Any tellurites precipitateout leaving selenous acid, H2SeO3, in solution.

Preparation of the catalyst according to the invention comprises in general first spraying the active carbon, more strictly the active carbon pellets, in an impregnating drum in a conventional manner with a palladium nitrate solution, thoroughly drying the product at elevated temperatures and then, in a second impregnating step, spraying on an ammonium polysulfide solution or an aqueous solution of selenous acid and finally again thoroughly drying at elevated temperatures.

Other suitable catalysts are cyclohexane-insoluble, preferably oxidic, compounds of selenium or tellurium, such as tellurium dioxide, tellurous acid, selenium dioxide or selenous acid.

Low fat milk-, whey-products are adjusted for example with oats comprising high amounts of amino acids, vitamins by preference vitamin K and E and provitamin A (carotine), minerals such as phosphor, iron, cobalt, zinc, aluminum, potassium and the constituents, boric acid, selene, iodide.

Brönstedt acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, chlorosulfonic acid, phosphoric acids such as ortho-, meta- and polyphosphoric acids, boric acid, selenous acid, nitric acid, acetic acid, propionic acid, haloacetic acids, such as trichloro- and trifluoroacetic acid, oxalic acid, p-toluenesulfonic acid, acidic ion exchangers, acidic zeolites, acid-activated fuller's earth, acid-activated carbon black, hydrogen fluoride, hydrogen chloride, and the like.

The tellurite Na2TeO3 is acidified with sulphuric acid and the tellurium precipitates out as the dioxide (leaving and selenous acid, H2SeO3, in solution).

The catalytically active metals can also be employed in an ion exchanger bonded form. If the metal is present in the form of a cation, strongly acid ion exchangers, for example crosslinked polystyrene having sulfo groups, are suitable; or if the catalytically active element is present in an acid form, such as selenous acid or a molybdate, it is also possible to use strongly basic ion exchangers, for example crosslinked polystyrene having tertiary or quaternary ammonium groups.