IL23255A - Process for the hydrogenation of nitric oxide with the aid of platinum catalysts - Google Patents

Description

for the of oxide with the aid of platinum catalysts AG TO PA can be reduced to hydroxylamine in an acid medium by hydrogen with the id of catalysts containing The time during vhich one and the same batch of the catalyst can be used is its effectiveness gradually It is that the of platinum catalysts in dilute sulphuric acid can increased of the sulphuric acid with oxidizing is also known that in the catalytic hydrogenation of nitric oxide the containing talyst can reactivated by treated riodically with pure nitric it has now been that silicon has an adverse effect on the life of such a platinum It has been established spectrogrsphieally that a platinum c talyst which has inactive after prolonged use in the hydrogenation of nitric bears a deposit of silicon or a silicon thus inactivated can be regenerated by means of hydrofluoric whereafter no silicon can be detected on it any has been according to the that if the hydrogenation of nitric oxide is carried out in a the life of one and the same batch of the cat much consists in a for the hydrogenation of nitric oxide in an acid medium the of wherein the hydrogenation is carried out in an environment vhich is poor or free Such an environment free or poor silicon apparatus lined with rubber or thermoplastic or If and when catalyst be freed from impurities in a manner per The invention is illustrated by the following to which it not of temperature are in degrees In Examples reference made to the accompanying drawing which apparatus for carrying out the of this A glass vessel 1 is charged with 1 litre of an aqueous solution containing 3 of sulphate and 176 g of sulphuric in which g of platinum catalyst Pt on activated is kept in suspension by stirring by Means of a stirrer temperature is kept at by hot water which flows through a heating jacket surrounding the vessel are oxide and hydrogen in a vessel litres of SO and 16 litres of per arid mixture is duced through the pips 4 into the 126 of phuric acid per hour are supplied continuously to the vessel 1 through a feed pips time to much solution drawn off through pipe 6 that the liquid volume 1 litre is maintained in the vessel Unconverted gases are carried off through the pipe During the first 120 the yield of is of the the activity of the catalyst As the initial concentrations of 193 g of hydroxylamine sulphate and 176 g of sulphuric acid per litre have to be maintained in the reaction the feed acid as aa the output of gradually as shorn in the hour up to 120 hours 150 hours 74 hours 22 The catalyst which silicon or a silicon compound whieh is thus obtained is in the course of the by treatmen acid at room temperature for 1 hour and can then returned into the regenerated catalyst has the same activity and life span as produced of nitric oxide with the acid of a platinum is carried under the conditions as described in in an iron vessel onto which a layer of rubber has been vulcanised She catalyst shews no drop of activity after 200 same effect is attained wit a protective coating of vinyl polytetrafluoroethylene or insufficientOCRQuality

Claims (1)

1. 5 A proeese for the ox oxide in a acid medium with the wherein the hydrogenatlon carried out an environment which is poor or free proeese according to wherein the natlon ie carried out an apparatus lined with rubber or a thermoplastic or thermosetting synthetic A proeese for the regeneration of a platinum for in process according to Claim the catalyet is freed from eilieon impurities by treatment with hydrofluoric For the PARTNERS insufficientOCRQuality