IL26453A - Nitrous oxide production - Google Patents

Description

e oxide production The State of Ministry of Defence 25172 The concerns the manufacture of nitrous Nitrous oxide among as rocket fuel and is in high An efficient and economic method for its production therefore an important industrial It ie known that a variety of metals and metal alloys that are normally either not attacked at all or attacked only very slowly by nitric acid are passivated by treatment with Examples of such metals and metal alloys are various kinds of stainless Inconel alloy containing approximately Or and and their All metals and metal alloys which are characterised by a passivation upon treatment with nitric acid will be re to hereinaf er for short as of the kind It is also known that the of metals of the kind s ecified to acidic attack can be Increased by oathodio Such a protection consists in connecting the metal as cathode into an electrolytic circuit and it is known that thereby the rats of corrosion of metals of the that the rats of their attack by It has surprisingly been discovered that if a metal of the specified Inserted Into and simultaneously therewith connected as cathode an electrolytic and the current density on the cathode as as the aoid concentration and temperature suitably selected metal a eloser desoriptloa of this phenomenon and its practical applicaion see for example Israel Patent Speelfieatloa a diseolution of metals of the kind specified thus depeadeat oa three parameters the current density oa the the aoid aad the These three parameters wiU be referred to hereinafter for short For each metal of the kind specified there exist various values for each of diseolution resulting in combinations of which does not produce any appreciable dissolution of the while an increase of the value of of the parameters will lead to Amy sueh combination of values for the dissolution parameters which does not yet produce any appreciable dissolution of the metal while an increase of any of the values will lead to in other constitutes the demarcation between aad will be to hereinafter for short as It is quite clear that for each metal exists a large number of threshold Thus for a givea current density oa the cathode and a given temperature a very definite concentration has to be selected in order to result in a ooabination of current temperature aad aoid concentration current on the cathode is tha aold concentration must ba aa order to obtain this another threshold In aooordanoa with the present invention it has surprisingly bean that if a metal of the kind la Inserted into an aqueous nitrio aold solution and aonneeted aa to a source of and a combination of the dissolution parameters is selected which does not exceed a threahold combinatio is produced at the Consequently the invention consists in a process for the production of nitrous oxide comprising inserting into an aqueous nitrio acid solution two electrodes of which the one is of a metal of the kind specified and the other is of a conductive material that inert to nitric acid under the operational connecting the electrode of the metal of the kind specified aa oathode and the inert electrode aa anode to a source of to produce an electrolytic selecting values for the dissolution parameters herein which yield a combination that does not exceed a threshold combination herein allowing an eleotric current to in said circuit and withdrawing a nitrous oxide containing gaa mixture from near the Examples of materials for the inert anode are various noble metals and their such for is believed that the production of nitrous oxide on the is due to a cyolio passivation and the desorbed with simultaneous formation nitrous The method according to the invention superior all known methods the production of nitrous oxide Tooth as regards equipment and energetic and is therefore considerably this method eoud not been anticipated from anything known the As a rule there is obtained in accordance with the invention at the a mixture containing in addition to nitrous oxide also elementary oxygen and hydrogen in varying proportions depending oa the For many purposes mixture can be used as is while for other purposes purified nitrogen may be isolated from that mixture by a method known per In the accompanying drawing there is by way of example a laboratory seals apparatus carrying out The apparatus here two communicating vessels 1 and 2 as anode and oathode Vessels 1 and 2 through a duet fitted with control valves 4 and 5 with a funnel 6 serving for the supply of Compartment is fitted with an inert anode and 2 fitted metal of the kind specified serving as Compartment 1 is further fitted an vessel 8 comprising an inlet valve 9 an outlet valve Teasel 8 serves for collecting the gaseous anode compartment 2 fitted with two elongated vessels a and He inlet 12a and and outlet valves and Teasels 1a and lib serre for collecting the gaseous cathode products and are designed for alternating use so that the apparatus may operate The invention Illustrated by the following Examples without being Halted In all these an apparatus of the kind described was having a platinum produced from at using as cathode stainless steel Current densities of and were used and the results are given in the Table belowt Concentration of Cathode stainless steal Concentration of 200 Cathode stainless steel Current density of the gas in the oathoda the lia V Total 15 72 28 20 75 24 0 40 27 55 0 50 44 45 80 62 50 0 02 Concentration of Cathode nuclear uranium for purified Concentration of Cathode aolear uranium Concentration of Cathode titanium density on cathode 40 the composition of the gas in the eathode expressed In volume pereent was aa 0 Concentration of 2S Cathode Zlroaloy 2 Current density on the eathode 40 The composition of the obtained in the eathode expressed in percentwas aa 21 21 52 Concentration of 2 N Oathode 2 Current density on the cathode 50 The composition of the gas obtained in the oathode expressed in percent as followst 30 10 1 60 As oan be seen from the foregoing Examples the various dissolution parameters are variable within wide Thus the current densities on the oathode stay be within the range of 1 The operational temperature can be selected up to near the boiling point but as a rule lower temperatures will be preferred because of eorroslTeneas of boiling nitric The preferred range of the nitric aoid concentration is from 1 to insufficientOCRQuality

Claims (1)

1. particularly described and ascertained the of our said invention and in vhat manner the same to be deolare that vhat we claim Process for the of nitrous oxide comprising inserting into an aqueous nitric aoid solution two electrodes of which the one is of a metal of the kind specified and the other of a conductive material that inert to nitric under the operational connecting the electrode of the aetal of the specified aa cathode and the electrode as anode to a source of to produce an electrolytic selecting values for the dissolution parameters herein which a combination that does not exceed a threshold combination herein allowing an electric current to flow in said circuit and withdrawing a nitrous oxide containing gas mixture from near the Process according to Claim wherein the current density cm the cathode la within the range of 1 to Process according to Claim 1 or wherein the nitric acid concentration is within the range of 1 to Process according to Claim substantially as A nitrous oxide containing gas whenever obtained by a process according to any one of 1 to Sated 4th day of 1966 insufficientOCRQuality