摘要:
For the preparation of anhydrous sodium dithionite by the reaction of sulfur dioxide with sodium formate and caustic soda in the presence of organic solvents, sulfur dioxide is passed, together with the formate, into a liquid containing all of the caustic soda required for the reaction. This initial liquid may contain, in addition to the caustic soda, a portion of the sulfur dioxide or formate required for the reaction.
摘要:
In a process for the manufacture of sodium dithionite by reacting sulfur dioxide with sodium formate and aqueous sodium hydroxide solution in the presence of methanol, an aqueous methanolic solution of sodium formate is first produced by reacting carbon monoxide with sodium hydroxide solution in an aqueous medium, containing from 1 to 50% by weight of methanol, based on the amount of water, at from 80 to 120.degree. C. under a pressure of from 10 to 40 bars. The resulting aqueous methanolic solution can be reacted directly, in the conventional manner, with sulfur dioxide and aqueous sodium hydroxide solution to give sodium dithionite.
摘要:
Finely divided metal oxides produced by combustion of metal carbonyls are separated from the stream of gas by filtration. Before filtration, the stream of gas is subjected to a permanent change of direction in a tubular zone. This change of direction must be sufficient to cause a centrifugal acceleration which is from at least 1,000 to 10,000 times the acceleration due to gravity.
摘要:
In an electrode suitable for electrolysis of aqueous sodium chloride or potassium chloride solutions, at least the outer layer contains spinels, specifically a mixture of the individual spinels of iron and of cobalt, the weight ratio of iron spinels: cobalt spinels being from 30:70 to 90:10.The electrodes are produced by applying a powder mixture of iron spinel and cobalt spinel to a substrate by a plasma spraying process wherein argon is used as the plasma gas and the spraying energy is from 6 to 30 kW.
摘要:
In an electrolysis cell with anodes and cathodes which are provided with openings, the cathode chamber is separated from the anode chamber by a diaphragm. The latter consists of a porous layer of oxides or oxidic compounds of the elements of sub-group 4B of the periodic table, of aluminum, of the rare earths or of chromium. The diaphragm is applied to that side of one of the electrodes which faces the counter-electrode.
摘要:
Manufacture of electrodes consisting of bases of valve metals with electrochemically active coatings applied thereto. The electrodes are pre-treated before the said coatings are applied, the pre-treatment comprising treating the base with hydrogen.
摘要:
Magnetic recording tape especially suitable for use as video tape and computer tape, comprising a base carrying a magnetic coating which consists essentially of a dispersion of a finely divided magnetic pigment and at least one lubricant in an organic binder. The lubricant is a compound of the formula ##STR1## IN WHICH N IS AN INTEGER OF FROM 3 TO 8 AND R.sup.1 and R.sup.2 are an alkoxy or aralkoxy radical or conjointly are an alkyldioxy radical of 3 to 18 carbon atoms. A magnetic recording tape prepared with a high proportion of such a lubricant is distinguished by high abrasion resistance coupled with a minimum transfer of material to the magnetic heads even under fluctuating climatic conditions.
摘要:
Cyclic phosphorus nitride esters are prepared as flameproofers of high durability for use on regenerated cellulose. The known synthesis from cyclic phosphorus nitride chlorides with alcohols in the presence of amines is controlled under specific temperature conditions such that desired side-reactions permit the production, in a simple manner and in very high yields, of products showing a durability to washing not hitherto achieved.
摘要:
A process for the manufacture of wear-resistant magnetic recording media comprising a dimensionally stable base, a thin ferromagnetic metal layer, containing cobalt and/or nickel, firmly bonded thereto and a thin protective layer applied thereon. The protective layer is produced by treating the recording medium in a liquid basic medium, containing gaseous oxygen, for from 1 to 60 minutes at from 5.degree. to 70.degree. C., washing and drying the treated recording medium and then heating it in air at from 170.degree. to 300.degree. C. This method offers a particularly simple way of providing the ferromagnetic layer of the recording medium with a thin but uniform, mechanically stable and wear-resistant protective layer.