摘要:
A process for the preparation of PVP-iodine by reacting polyvinylpyrrolidone powder with elementary iodine at from 70.degree. to 100.degree. C. The reaction is carried out in the presence of formic acid, oxalic acid or an ammonium salt or amide of carbonic acid, formic acid or oxalic acid. The process avoids the disadvantage of long periods of heating, which can result in degradation of the polyvinylpyrrolidone, and is particularly suitable for the preparation of a stable PVP-iodine using a low molecular weight polyvinylpyrrolidone.
摘要:
A process for reducing the residual monomer content of a copolymer prepared by copolymerizing vinyl esters and N-vinyl-lactams in a solvent in the presence of a free radical polymerization initiator. Following the main polymerization, from 0.05 to 0.5% by weight, based on the monomers employed, of di-tert.-butyl peroxide, di-tert.-amyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis-(tert.-butylperoxy)-hexane, 2,2-bis-(tert.-butylperoxy)-butane, 1,1-bis-(tert.-butylperoxy)-3,3,5-trimethylcyclohexane, 4,4-di-(tert.-butylperoxy)-butyl valerate, or a mixture of these, is added to the reaction mixture and the after-polymerization is carried out at a higher temperature than the main polymerization.
摘要:
Polyvinylpyrrolidone-iodine, manufactured by reaction of iodine and a polyvinylpyrrolidone obtained by polymerization in an anhydrous organic solvent in the presence of a source of free radicals and optionally in the presence of a heavy metal of atomic number from 23 to 29, in the form of a complex compound or of a salt with an organic acid, as a co-activator, followed by steam distillation of this polyvinylpyrrolidone, if appropriate. The PVP-iodine of the invention is very stable and can be used as a disinfectant.
摘要:
A process for the preparation of PVP-iodine having an iodine:iodide ratio of about 2:1 and a partition coefficient of 180-250, by reacting PVP with elementary iodine in the presence of formic acid, oxalic acid or an ammonium salt or amide of carbonic acid, formic acid or oxalic acid, in aqueous solution.
摘要:
A gas generator for an airbag which contains the pyrotechnic mixture as a propellent charge. The propellent charge is in the form of granulates which generate a non-toxic gas. A space encompasses the container for the propellant charge and is separated from the airbag by a gas-permeable separator so as to generate a higher pressure in the space than in the airbag during inflation of the airbag.
摘要:
A process for the preparation of a carboxylic chloride of the general formula I ##STR1## in which R denotes C.sub.1 -C.sub.30 -alkyl, C.sub.2 -C.sub.30 -alkenyl or C.sub.2 -C.sub.30 -alkynyl, from a carboxylic acid of the general formula II ##STR2## in which R has the meanings stated, and phosgene COCl.sub.2 (III), in the presence of a catalyst adduct comprising phosgene and N,N-disubstituted formamide of the general formula IV ##STR3## in which R.sup.1 and R.sup.2 are independently C.sub.1 -C.sub.3 -alkyl or R.sup.1 and R.sup.2 together form a C.sub.4 - or C.sub.5 -alkylene chain which may or may not be interrupted by an oxygen atom or by a nitrogen atom carrying a C.sub.1 -C.sub.3 -alkyl group or CHO, the product being isolated by phase separation, wherein the amount of phosgene added to the formamide (IV) is from 20 to 70% molar, based on the formamide.
摘要:
In an electron beam generator where the heating current for the cathode is transformed by an insulating transformer 7 disposed on the high-voltage insulator 4 of the beam head, the primary winding of this insulating transformer 7 being connected to ground potential, and where a single-pole high-voltage connection 2 and a single-pole high-voltage cable 2 connect the beam head 3 to a high-voltage generator 1, the high-voltage cable 2, at its terminal ends, has a protective resistor 10 corresponding to the surge impedance of the high-voltage cable 2 in order to reduce the damages to insulating and component parts.
摘要:
Acrylates or methacrylates I ##STR1## (A and B=C.sub.2 -C.sub.5 -alkylene, R.sup.1 =H, CH.sub.3) are prepared by reacting an acrylate or methacrylate II ##STR2## (R.sup.2 =C.sub.1 -C.sub.4 -alkyl) with a heterocycle III ##STR3## in the presence of titanium alcoholates chelate compounds of the metals titanium, zirconium, iron and zinc with 1,3-dicarbonyl compounds.
摘要:
After the pressure of the gas in a first chamber reaches the maximum value, the cover for the air bag is broken up. The cover is broken at the pressure of the maximum value, and there is almost no waste of the gas energy. Thus, the cover can be broken up by the small amount of the gas energy and the heat losses are extremely reduced, so that the amount of the gas generating agents are made small. Also, the cover is broken by the burning of the first chamber and the air bag is inflated at the first stage by expansion and inertia of the gas. There is provided a mechanical timing for ignition delay, and then the bag is fully inflated by the burning of a second chamber. Therefore, the bag can be desirably inflated.
摘要:
A multistep process for the continuous preparation of organic polyisocyanates, preferably aliphatic or cycloaliphatic diisocyanates, by reacting the corresponding organic polyamines with carbonic acid derivatives and alcohols to give monomeric polyurethanes and pyrolyzing the latter involves separating the resultant polyisocyanates and worthless residues in certain reaction steps and recycling the reusable by-products into earlier steps.