MXPA96005488A - Process for the preparation of hydroxylammonium salts - Google Patents

Abstract

The present invention refers to a process for the preparation of a hydroxylammoniumásalt via a nitrate ion catalytic reduction in an acid medium in the presence of an activated catalyst, said catalyst comprising vehicle particles having palladium and platinum-containing metallic particles, the relative concentrations of palladium and platinum in each particle being almost the same;particularly, the concentration of platinum in each metallic particle has a standard deviation, given in percent by weight in relation to palladium concentration, lower than absolute 4 percent.

Description

PROCEDURE FOR THE PREPARATION OF HIDRQXILFHIONION SALTS The invitation refers to a procedure for preparation < 1o a sl de drox lamomo t ravés of the μ5 cat.al.Hica reiluccion of nitrate ions in an acid medium, ne of a ca + al activated Li 'r, said or to the hunter com rend particles of vehicle with ine + al icas particles < μ,? e co t n palladium and platinum. An api icator a number of salts of hydroxyammonium is used in the preparation of orthone or aldehyde extracts, in particular the preparation of oxycyclohexanone oxyhydrogen from the clohexanone. The oxyhexanone oxuna can be arranged in eaprolac + arne from which nylon is prepared. Consequently, the synthesis of salts of larynx dro droxi is commonly coupled with other known methods, such as 1? preparation of one of the cloal canon. The salts of ammonium drox are also used in the production of ant IOX i dan t.e, aux 11 res of t i nc i on and sub t aan < ? u i rn i cas fotograf Leas. A cyclic procedure is known for the preparation of an oxygen. Is the reaction medium? The pH of the solution is determined by using an acid, for example phosphoric acid and / or sulphuric acid and the buffer salts derived from these acids, for example, alkali salts and / or ammonium salts. I "n the synthesis of hydroxanthine, the ions of iLi at.o xides Nitrogen oxide, for example, are converted to ions of 1'ud? Nitrogen oxide with the help of hydrogen according to the following reaction: 2 11+ * NO 3 - * 3 H2 - "> NH3011 + * 2 1120 the calendars is for 1 < t preparation of salts \ hydr? However, the activity and selectivity of these catalysts can be improved.The purpose of the invention, now, is to provide a procedure in which the <is commercially available ont o available from Johnson [•> Matthey and uegussa. At this time, they have an even better selectivity and / or activity.10 This purpose is achieved because the relative concentrations of palladium and platinum in each metallic particle on the vehicle particles are substantially the same. this is not the case with the present commercial catalyst. "Substantially the same" herein is defined as a standard deviation of the platinum concentration in each palladium-metal particle, in percent by weight. weight, at most 4% absolute. 2U Preferably, the normal concentration thus defined is smaller than 3.52, in particular smaller than the 3%. The weight ratio of the pal d 0 and the catalyst in the catalyst can be between F > : k and 9.9: 0.1. Preferably the relationship is in? : .3 and 9 »Í5: (1.?) In principle, any material that is stable in the reaction medium can be used as the vehicle, for example, carbon activating, grapto or,? The mean particle size of the vehicle is in practice smaller than bf μm .. "Average particle size" is understood to be ^ 0 in volume of the torque which is larger than this diameter. However, a vehicle with which at least 90% by volume of the total amount of particles has a diameter of less than 2 (1 μr) is also suitable as a suitable particle. of the vehicle, the removal of the catalyst-through l filtering can be difficult. Normal filtration can be achieved without adversely affecting the activity of the catalyst by adding an amount of inert material, for example vehicle material without metal particles, having a particle diameter that exceeds that of the W vehicle particles. 1 I did cat- lizer, for example approximately 20-100 j a. An amount of 0.3-10 g of inert material per gram of catalyst material is adequate. In general, the average particle size exceeds 0.1 μm. If a crossover flow filtering technique is used, the particle size preferably exceeds 1 μr, in particular it exceeds b μm. If a conventional ace filtration technique is used, the vehicle particle size preferably exceeds LO μrn. The catalyst must be activated; the catalyst can be activated by the presence of one or more catalyst activators. FL Catalyst Activator can be an element of the group that includes Cu, fig, iu, SM, Oa, In, I, Oe, S, Ph, Rs, Sh and Hi. The compounds that < ont ic-nen the items in question also '--e can use < orno 't i vadoi os do < "aa 1 i zador, for example xidos, nitrates, phosphates, sulfates, halides, tart rata, oxalate, phytopytes and acetates.The elements or their compounds can be applied directly to the catalyst or can be added to the reaction medium A very good result can be obtained if approximately Q.OL-S mg, preferably around 0..02. to about 4 mg, of element (s) of the above group is present per gram of catalyst, in case the catalyst has a surface area between about b and about 10 2 / g of catalyst. The larger the surface, the more active it will be needed. Ib The pressure of I-I2 at which it takes place is to reaction is generally between 1 and 50 f > apas, pre feí 1 b ently ent e b and 25 barias. At the total pressure of the reaction, an inert gas can be contacted with the hydrogen. Fl H2 used may or may not be purified. Purification may take place with the cyanide, For example, activated carbon for the purpose of removing organic components, a palladium catalyst for the purpose of removing oxygen and / or zinc oxide to remove sulfur and ruthenium to promote the conversion of 00 and OO2. If either L 1 or H 2 is mixed, the helium can be purified using activated charcoal. Other inert gases such as arg n, metaL or nitr geno also < -on suitable. l 'Vile de fu drox i lamen i o can ?? epnrar a pll t; nt e 1 and b, μ releí ib! e ent e i and 4., Fl p | - | do l < The reaction can be maintained by the addition of a strong mineral acid, such as hydrochloric acid, nitric acid, sulphuric acid or phosphonous acid or salts (ie, the temperature can vary between 20 and 90 ° C; it uses a temperature of between 30 and P () ° 0. The invention will be elucidated with reference to the following examples, without imitating the same.

EXAMPLES AND COMPARATIVE EXPERIMENTS The examples and comparative experiments were carried out in a reactor or pressure on thermostat made of chrome-nickel steel, which have an internal diameter of RU min and a volume of approximately 100 ml, in accordance with the following procedure: the reactor was equipped with screens of 0 m width and a turbine agitator of ñ pal (s with a cross section of 40 inrn and 10x10 in. blades) The reactor was operated as a three-phase suspension reactor with a continuous production of the liquid and gas phases, while the solid catalyst powder was retained in the reactor with the aid of a Teflon membrane filter in the liquid outlet. contained 3.2 moles / liter of nitric acid dissolved in a pM regulator of phosphorus acid (3.3 mmole / liter aqueous plus 0.1 mole / liter of UaOI-l was fed to the teac.tor) in the absence of a The volume of the liquid in the reactor was maintained at an onstant- value of L15 mi. Hydrogen was also fed to the reactor. The reactor pressure was maintained at a constant level with the help of a regulator. The pressure at the gas outlet; the evolved gas was cooled before the pressure regulator, while the total gas flow velocity was then given to the pressure regulator. The partial pressure of hydrogen was varied to a constant total pressure by mixing with hel 10. The reactor was operated at a constant pH of 1..8. For this purpose, the sum of H + through the power supply was adjusted to the amount consumed in the reactor through a measurement (pH at the outlet of the liquid and adjustment of the feed flow rate). All the products were analyzed online, the gas concentrations of N2, NO and N2 in the dosed gas were measured with the help of gas chromatography. U +, in addition to the remaining H +, were determined by an automatic crusher, the catalysts were fed to the reactor, the concentrations were shown in the following tables, the purpose was to ensure constant activity in the reactor, which means that More or less a catalyst was used, depending on the catalyst activity, after which the reactor closed and became inert with the helium helium, after becoming inert, it is </ lt; -> < > pressure from '? 0 to I-I2 and the river was filled with 115 ml of l liquid that had the fields ic 1 > n of the product. After the operation was started introducing food material through the pump.The temperature was 50C and the agitation speed was 130U r pin (rotations per minute) .. The cataLizador is activated with the help of Oe, which is dosed, like a "-eluci n of Oe? 2 in water or release" e > n or l feed material, in the steps during ours < - > of the experience, l ?? The dose was added every time within a few minutes (between 1 and 10 minutes after the start). The activation was made in the following way; a first dose of approximately 0.0625 MI (monoeapa) of Oe, followed by the same amount after (Je 24 hours, a total (Je 0.125 MI., Then 0.0 (525 MI of Ge every 48 hours, to a total of 0.31 or 0.375 ML) The concept "monolayer" is defined as follows: a mon? number of Pd and / Pt on the surface of the metal particles. can be determined with the aid (Je qu mioadsorcion Je 00, with the assumption of each noble metal atom on the surface absorbs a molecule of 00. the activation was made in steps because the optimal degree of activation is not know beforehand .. ') ^ ^ The flow rate of feed was between 0.9 and 5 ml / nun, depending on the activity of the catalyst, the coni.ent ra < . ion of ni dr ox i Lamí na > every time -, íondo t i ?? cam-) nt e «le 0.9 1.0 ?? oL / 1 i < i o, l activity i), oxpiesada in mino lo 'i of NO3- / gme t. hr, was calculated as lu sum of the yield of? I product of 5 with consistency with equation (1): F-? - Y-HYfiM • Y NI-- + »• Y-N2 + Y -NO + Y-N2O (1) where Y? e? reserves the yield, hyam? e? resent < -? 10 hydrox 1 lamí n. The amount of metal in the catalyst in grams is gmet »The yield of the products in the liquid phase was calculated on the basis of the normalized concentrations or in mol / liter, the flow rate of liquid L Qf eed in ml / inin and the amount of precious metal introduced with the catalyst, Ib expressed in g (gme), according to (2): Y (x) - c (?) * GfBed "< ñf) / gmet (2) where x can be hi droxi 1 ami na or NH <; + .. Ofßed is calculated) to 2 (1 from the weighted decrease in the feed material (in grams) with the time and the density of the liquid (g / ml) that was measured before being used., The yields of the products in the gas phase were calculated from the concentrations c in percentage) 5 in volume measured by the gas chromatograph, the flow velocity of the gas evolved 0gas in Stl / hr and the amount of metal Y (y) a * l ~ (yJ / 10m * a a. * 1000 / (24.04 * gmet) 3) where y represents N, 110 or N20 and in 'where a - l in the case of NO to -2 in the case of N2 and 2 I 1 l actor 24.04 is the volume of molar gas in ltrs to an atmosphere, 20 ° 0"Qgas was calculated by summarizing the gases (he measured supply of measured gases and the calculated gaseous products formed, after the subtraction of the consumption of H2 sum calculated for all the products, the selectivity S, expressed in percent, of each catalyst was calculated with the help of the lentnnionto previously determined Y and the activity R of? Rom agreement (z) 1 0 Y (;. ') / fi) where z represents one (Je ios product1-, hi droxi 1 am 1 na, NI- +, N2, NO N20.) the selecti ies therefore was based on NO3-c? nvertido and s calculated on? the base of the products med 1 do to the weight ratio of the pallet and the plot of the separated metal particles is determined with the help of microscopy or unique l-ransmission (M "M) are element analysis, X-ray analysis (Energy dispersion (I l) X), Device used I or VG HB-ü I EMR of Vacuum Genera t 01, 5 equipped with a field emission gun (FEO) The catalyst was imbibed into a metal filter (PMMfi), from which slices of thickness were cut, then 5 particles of the vehicle. were selected, after which 5 individual metal particles were measured per particle (vehicle), 4 metal particles on the board of the vehicle particle and a metal particle in the center of the vehicle paiticula. The slices were then irradiated in a transmission electron microscope (fl - I) with the help of an electron beam, the acceleration voltage was 120 L'V. This led to the generation of X-ray radiation specific to elemente) in the slices, which); They detected on the help of an I LUX Explorer connector detector in 500 seconds. I to Pd / P < was calculated from the measured amount of X-ray radiation on the basis of standardization at 100% concentrations of Pd «Pt" concentrations are shown in the tables.

Example I and Comparative Experiments A-C In the first series of experiments the catchers were tested at a pressure of 4 0 ba ry of H2. The ca ta li zadores I 1 they had a ratio of 1) 0-20 of Pd / Pt "the activity and • • ectivity are given in the 0.31 ML of Ge, the dose giving \ i \ -result a maximum selectivity Icteia hi drox i 1 anu na" The catalyst with a deviation of Pt not wrong in the Pd / Pt alloy of 2.5 showed both a higher selectivity and a higher selectivity, as shown in Table I.

TABLE I or Example II and Comparative Experiment D In these two experiments, the catalyst used '- > n the experiment co pai t i o C and example I were used at a pressure of H2 of 12 bar, the activity and selectivity are given to O,.;) 75 ML Ge. The use of a lower H pressure makes the activity and selectivity decrease. Unexpectedly it has been found that the selectivity of the coniopiinhu catalyst with 1 to 1 invention is much less.

BOX II Examples III-V and Comparative Experiment E The catalogs with a Pd / Pt rating of: i have been initiated by Eivjclhard and a commercial catalyst with a relationship (Je Pd / Pt (Je 8: 2 supplied by Johnson Mat t hey * - , e? re) baron at 10 barias of H2 at 0.31 Mt de Ge. so obtained a high selectivity at an acceptable activity compared to the P experiment. The results are shown in table III ,.

TABLE III s > ir7 Examples VI and VII and Comparative Example F Catalysts with an ionization (Je Pd / Pt of .1 f-uer '(> n supplied by Enuelhard, a common catalyst supplied by Johnson Mat.they with a Pd / Pt e ü rating: 2 were tested at 10 bar of H2 •• The measurements were taken at () .. 3 5 mi of Ge .. The results (in the TV box showed that the selectivity is very good for me.

TABLE IV oo 10 Examples VIII-XI and Comparative Experiment G catalysts with a Pd / Pt ratio of -1: 1 and (1: 2 were supplied by Engelhard and a commercial catalyst with a Pd / Pt ratio of 8: 1 'supplied by Johnson Hatthey. tested at 10 bar of H2 0.25 ml of Ge. selectively improved a lot again, see the results in table V ..

TABLE V or C '* est imat ion 'I Example XII and Comparative Experiment H The catchers, with the characteristics shown in o? VT box < e tested to * • > several of I-I2, a [).? b mi do h Selec i ament < e show improvements in the c: uadre- / VI TABLE VI

Claims (1)

1. ; • '] NOVEDRD OF INVENTION CLAIMS ! 1. A process for the preparation of hydroxyl ammonium salt through the catalytic reduction of nitrate ions in an acid medium, in the presence of an activated catalyst, said catalyst or in in particle particles with they contain palladium and platinum, characterized in that the relative concentrations of palladium and platinum in each metal particle are subst anced thereto, the platinum concentration in each metal particle has a 'minor' standard deviation of 4 ' Absolute%., 2. A process according to claim 1, further characterized in that the concentration of platinum in each particle of met.il has a standard deviation less than 3.5% absolute. '> - A method according to claim 2, further characterized in that the concentration of platinum in each metal particle has a minor standard deviation of 3% absolute. 4 ..- A procedure according to '• u l' | u? Or < \ r the indications 1-3, also characterized because the palladium ratio: plat i not in each metal particle is between? h 7.3 and y .9: ü .1. ! > . A procedure of compliance with any d? 2 and ls rei indications 1-4, char? i zade; also because the vehicle material consists) 'Je > i bon acti ado «jralito or si 1 i ce. b. A method according to any of claims 1-5, further characterized in that the particle size of the vehicle is between 0.1 j ,? and 50 j,? 7. A method according to any of claims 1-6, characterized by the fact that the catalyst is activated by the presence of one or more elements of the < A group consisting of Cu, 0 < j, Ru, Cd, Ga, l "n, TI, Ge, n, l'b, í-ls, Sb and?)?" 0.- A procedure is described in the introductory section and is described below. examples ,.