Kinetics and Mechanism of Ru(III)-Catalyzed Oxidation of Paracetamol by Chloramine-T in Aqueous Acidic Medium

The present paper deals with the kinetics and mechanism of Ru(III)-catalyzed oxidation of paracetamol by chloramine-T (CAT) in aqueous perchloric acid medium at 303 K. The experimental result shows a first order dependence on paracetamol at its low concentrations, but tending towards zeroth order at its higher concentrations. The reactions follow a first order rate dependence with respect to oxidant [CAT] and [Ru(III)]. The reaction showed negative fractional-order dependence on the rate for [H⁺] and p-toluenesulphonamide. Variation in [Cl^?] and ionic strength of the medium did not bring about any significant change on the rate of reaction. The decrease in the reaction rate with decrease in the dielectric constant of the medium was observed in the oxidation of paracetamol. Kinetic and equivalence studies together with product analysis, observed effect of dielectric constant of the medium on the rate of reaction and activation parameters furnished a basis for the formation of a common reaction mechanism for the Ru(III)-catalyzed oxidation of paracetamol by CAT in the acidic medium.     

Mechanistic Aspects of Os(VIII)/Ru(III) Catalysed Oxidation of L-phenylalanine by Ag(III) Periodate Complex in Aqueous Alkaline Medium

The kinetics of oxidation of ruthenium(III) (Ru(III)) and osmium(VIII) (Os(VIII)) catalysed oxidation of L-phenylalanine (L-Pal) by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at 27 °C and a constant ionic strength of 0.25 mol dm^?3 was studied spectrophotometrically. The involvement of free radicals was observed in the reactions. The reaction between DPA and L-Pal in alkaline medium exhibits stoichiometry as [L-Pal]:[DPA] = 1:1. The reaction is of first order in [Os(VIII)], [Ru(III)] and [DPA] and has negative fractional order in [IO₄ ^?]. It has less than unit order in [L-Pal] and [OH^?]. However, the order in [L-Pal] and [OH^?] changes from first order to zero order as their concentrations increase. The main oxidation products were identified by spot test and spectral studies. The probable mechanisms were proposed and discussed. The catalytic constant (K _c) was also calculated for Os(VIII) and Ru(III) catalysis at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed and thermodynamic quantities were also calculated. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The active species of catalyst and oxidant have been identified.     

Ru(III)/Os(VIII) Catalysed Oxidation of Gabapentin (Neurotin) Drug by Diperiodatoargentate(III) in Aqueous Alkaline Medium (Stopped Flow Technique): A Comparative Study

The kinetics of ruthenium(III) (Ru(III)) and osmium(VIII) (Os(VIII)) catalysed oxidation of neuroleptic drug, gabapentin (GBP) by diperiodatoargentate(III) (DPA) in alkaline medium at 27 °C and a constant ionic strength of 0.60 mol dm^?3 was studied spectrophotometrically. The oxidation products in both the cases are 1-(hydroxymethyl) cyclohexane acetic acid and Ag(I). The stoichiometry is the same in both the catalysed reactions i.e. [gabapentin]:[DPA] = 1:1. The reaction is of first order in Os(VIII)/Ru(III) and [DPA] and has less than unit order in both [GBP] and [alkali]. The oxidation reaction in alkaline medium has been shown to proceed via a Os(VIII)/Ru(III)-gabapentin complex, which further reacts with one mole of monoperiodatoargentate(III) (MPA) species in a rate determining step followed by other fast steps to give the products. The main products were identified by spot test and spectroscopic studies. The reaction constants involved in the different steps of the mechanism are calculated. The catalytic constant (K _c) was also calculated for both catalysed reactions at different temperatures. From the plots of log K _c versus 1/T, values of activation parameters with respect to the catalyst have been evaluated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII)>Ru(III). The probable active species of catalyst and oxidant have been identified.     

Mechanistic studies of ruthenium(III)-catalyzed oxidation of DL-methionine by hexacyanoferrate(III) in an alkaline medium

The kinetics and mechanism of ruthenium(III) catalyzed oxidation of dl-methionine by alkaline hexacyanoferrate(III) (HCF(III)) in an alkaline medium were studied spectrophotometrically at 30±0.1°C. The reaction was first-order-dependent each on [HCF(III)] and [ruthenium(III)] and fractional-order-dependent on [alkali]. The rate of the reaction was found to be decreased with the increase in [methionine]. The main product of oxidation was methionine sulfone nitrile (3-(methylsulfonyl)propanenitrile) and it was identified and confirmed by FT-IR and mass spectral studies. Further, no effect of added reaction product was observed. A plausible mechanism was proposed involving complexation between methionine and ruthenium(III) species, [Ru(H₂O)₅OH]²⁺. Thermodynamic parameters for the reaction, E _a and Δ S ^#, were computed using linear least squares method and are found to be 65.83±1.03 kJ/mol and?249.58±3.35 J/K mol, respectively.

     

Kinetics of glycine oxidation by N-bromophthalimide in the presence of sodium dodecyl sulfate

The kinetics of oxidation of glycine by N-bromophthalimide (NBP) were studied in the presence of an anionic surfactant, sodium dodecyl sulfate, in acidic medium at 308 K. The rate of reaction was found to have first-order dependence on [NBP] and fractional-order dependence on [glycine] and [H⁺]. The addition of reduced product of the oxidant had no significant effect on the rate of reaction. Increasing [Hg(OAc)₂] and [Br⁻] increased the rate of reaction, whereas a change in ionic strength (μ) of the medium had no effect on oxidation velocity. The rate of reaction decreased with a decrease in dielectric constant of the medium. HCN was identified as the main oxidation product of the reactions. The various activation parameters have been computed. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.     

Os(VIII)/Ru(III) Catalysed Oxidation of <Emphasis Type="SmallCaps">l</Emphasis>-Valine by Ag(III) Periodate Complex in Aqueous Alkaline Medium: A Comparative Kinetic Study

Abstract  

The kinetics of osmium(VIII) (Os(VIII)) and ruthenium(III) (Ru(III)) catalysed oxidation of l-valine (l-val) by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at 25 °C and a constant ionic strength of 0.006 mol dm⁻³ was studied spectrophotometrically. The stoichiometry is the same in both the catalysed reactions, i.e., [l-val]:[DPA] = 1:1. The reaction is of first order in [Os(VIII)], [Ru(III)], and [DPA] and has less than unit order in [l-val] and negative fractional order in [OH⁻]. Added periodate had no effect on rate of reaction. The products were identified by spot test and characterized by spectral studies. The catalytic constant (K _C) was also calculated for both catalysed reactions at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed and thermodynamic quantities were also determined. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The probable active species of catalyst and oxidant have been identified.     

Osmium(VIII) catalyzed oxidation of a sulfur containing amino acid—a kinetics and mechanistic approach

The kinetics of osmium (VIII) catalyzed oxidation of DL-methionine by hexacyanoferrate(III) (HCF) in aqueous alkaline medium at a constant ionic strength of 0.50 mol dm^?3 was studied spectrophoto-metrically. The reaction between hexacyanoferrate(III) and DL-methionine in alkaline medium exhibits 2:1 stoichiometry (2HCF:DL-methionine). The reaction is of first order each in [HCF] and [Os(VIII)], less than unit order in [alkali] and zero order for [DL-methionine]. The decrease in dielectric constant of the medium increases the rate of the reaction. The added products have no effect on the rate of reaction. The main products were identified by spot test. A free radical mechanism has been proposed. In a prior equilibrium step Os(VIII) binds to OH^? species to form a hydroxide species and reacts with [Fe(CN)₆]^3? in slow step to form an intermediate species(C₁). This reacts with a molecule of DL-methionine in a fast step to give the sulfur radical cation of methionine and yields the sulfoxide product by reacting with another molecule of [Fe(CN)₆]^3?. The rate constant of the slow step of the mechanism is calculated. The activation parameters with respect to slow step of the mechanism are evaluated and discussed.     

Investigation of electron-transfer reaction between alkaline hexacyanoferrate(III) and ranitidine hydrochloride – a histamine H2 receptor antagonist,in the presence of homogenous ruthenium(III) catalyst

The ruthenium(III)-catalyzed electron-transfer reaction between hexacyanoferrate(III) and ranitidine hydrochloride is studied in alkaline medium at 25°C and at an ionic strength of 1.10?mol/dm³. The reaction stoichiometry is established and is found to be 1:4, that is, for the oxidation of one mole of ranitidine, four moles of hexacyanoferrate(III) are consumed. The reaction products were characterized by spectral studies such as IR, GC-MS, ¹H-NMR and ¹³C-NMR. The reaction rate shows a less than unit order in substrate and alkali and a first-order dependence in oxidant, [Fe(CN)₆]^3? and the catalyst, ruthenium(III) concentrations. The active species of ruthenium(III), [Ru(H₂O)₅OH]²⁺, forms an intermediate complex with the substrate. The attack of complex by hexacyanoferrate(III) in the rate determining step produces a radical cation, which is further oxidized in the subsequent step to form the oxidation product. The effect of the reaction environment on the rate constant upon adding varying concentrations of KNO₃ and t-butanol was studied. The initially added products did not have any significant effect on the reaction rate. A plausible mechanism is proposed based on the experimental results. The effect of varying temperature on the reaction rate was also studied. The activation parameters for the slow step and the thermodynamic quantities for the equilibrium steps were evaluated.

The mechanism of title reaction has been studied and one mole of ranitidine consumes four moles of [Fe(CN)₆]^3?, as shown in the following equation:     

Osmium(VIII)/Ruthenium(III) Catalysed Oxidation of l-lysine by Diperiodatocuprate(III) in Aqueous Alkaline Medium: A Comparative Mechanistic Approach by Stopped Flow Technique

Abstract The kinetics of osmium(VIII) and ruthenium(III) catalysed oxidation of l-lysine (l-lys) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength of 0.15 mol dm⁻³ was studied spectrophotometrically. The reaction between l-lys and DPC in alkaline medium exhibits 1:2 stoichiometry in both catalysed reaction (l-lys: DPC). The reaction is first order in [DPC] and has less than unit order both in [l-lys] and [alkali]. Increase in periodate concentration decreases the rate. Intervention of free radicals was observed in the reaction. The main products were identified by spot test, IR and GC-MS studies. Probable mechanisms are proposed and discussed. The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The active species of catalyst and oxidant have been identified. Graphical Abstract The kinetic and mechanistic investigations of the reaction between DPC and l-lysine has been studied in presence of microamounts of ruthenium(III) and osmium(VIII) in alkaline medium. The monoperiodatoargentate(III), [Ru(H₂O)₅OH]²⁺ and [OsO₄(OH)₂]²⁻ are considered as the active species of oxidant, DPC, ruthenium(III) and osmium(VIII) respectively.      

Kinetics of oxidation of butadiene to crotonaldehyde

The oxidation of butadiene to crotonaldehyde has been investigated using an aqueous catalyst solution containing palladium chloride–cupric chloride in dilute hydrochloric acid. Unlike the oxidation of ethylene, propylene, etc., this oxidation was found to be a zero-order reaction with respect to butadiene. The effects of temperature and the concentration of Pd²⁺, Cu²⁺, Cl^? and H⁺ ions on the reaction rate were studied. The order of reaction with respect to Cl^? and H⁺ ions in this case (approximately 1.5 and ?0.25, respectively) is different from that observed in the case of lower alkenes.     

Ru(III)-catalyzed oxidation of N-acetyl-L-cysteine by methylene blue in absence and in presence of Cu(II) in acidic medium: influence of solvent and morphology

N-acetyl l-cysteine (NAC), the substrate used presently has got diverse medicinal applications and is widely used as a mucolytic agent. The oxidation of bioactive molecules, in general, involves metal ion catalysis facilitated by the participation of metal nanoparticles. In view of this, the oxidation of NAC by a phenothiazine dye methylene blue (MB), a model electron receptor, catalyzed by Ru(III) in the absence and in the presence of Cu(II) has been investigated in acidic medium. The concentration order in MB is zero, while the order in NAC is one and two in Ru(III)-catalyzed and Ru(III)-Cu(II)-catalyzed reactions, respectively. Hydrogen ions retard the rate in Ru(III)-Cu(II)-catalyzed reaction, whereas the rate increases linearly with increasing [Ru(III)] in both the systems. The rate increases with increasing [Cu(II)] and attains a limiting value. The addition of the reaction products does not affect the rate of reaction. The reaction is characterized by a large negative entropy of activation. The kinetic deviations of the reaction, explained by presuming the participation of a reactive form of the NAC molecule or its new conformational polymorph reported recently, indicate the regulatory influence of the morphology of nanoparticles.     

Electrocatalytic activity of [Ru(bpy)<Subscript>3</Subscript>]<Superscript>2+</Superscript> toward guanine oxidation upon incorporation of surfactants and SWCNTs

The homogeneous and mediated oxidation of guanine by [Ru(bpy)₃]²⁺ (2,2′-bipypyridine) in the presence of surfactants and single-walled carbon nanotubes (SWCNTs) has been investigated using cyclic voltammetry, repetitive differential pulse voltammetry and rotating electrode method. In acidic medium, the oxidation of guanine was controlled by mass transport process of [Ru(bpy)₃]²⁺ in solution, leading to a homogeneous electrocatalysis. In neutral medium, the result from emission spectroscopy suggested the formation of the aggregates containing [Ru(bpy)₃]²⁺, dihexadecyl phosphate (DHP) and guanine. The electrocatalysis of [Ru(bpy)₃]²⁺ toward guanine oxidation was promoted by anionic surfactant DHP and, however, hindered by an excess amount of hexadecyl trismethyl ammonium chloride (HTAC) or SWCNTs added to solutions. The electrocatalytic mechanism of [Ru(bpy)₃]²⁺ for guanine oxidation becomes evident, strongly depending on the presence of anionic or cationic surfactants and SWCNTs.     

Investigation of CO Oxidation Transient Kinetics on an Oxygen Pre-covered Au(211) Stepped Surface

The desire to explain the origin(s) of the unexpected catalytic activity of oxide-supported Au nanoparticles for CO oxidation discovered by Haruta and coworkers has stimulated numerous experimental and theoretical studies of Au nanoclusters in the gas phase and on metal oxide supports, and on Au single-crystal surfaces. In order to explore further the reactivity of low-coordination Au step sites, we have performed transient kinetics studies of CO oxidation on an O-precovered, stepped Au(211) single crystal surface. We found behavior similar to that observed previously on flat Au(111) and (110) surfaces; i.e., there is no evidence in these transient kinetics for any special reactivity associated with this stepped Au surface. The CO oxidation reaction rate was highly dependent on the initial oxygen coverage, and we determined an apparent activation energy for CO oxidation of ?7.0 kJ mol^?1 for θ _O ^init  = 0.9 ML. Within the Langmuir-Hinschelwood (LH) reaction scheme, we estimate an activation energy of E _LH = 20–43 kJ mol^?1 on this surface for CO oxidation via this pathway. This is somewhat below the value of 67 kJ mol^?1 predicted by recent theoretical calculations.     

Kinetics of absorption of oxygen in aqueous solutions: (1) acidic chromous chloride, (2) acidic titanous chloride and (3) ammoniacal cuprous chloride

The kinetics of absorption of oxygen in aqueous solutions of acidic chromous chloride and ammoniacal cuprous chloride were studied in a stirred cell. Both these reactions were found to be very fast and the theory of gas absorption accompanied by fast pseudo-m^th order reaction was used to analyse the results. The kinetics of absorption of oxygen in aqueous acidic solutions of titanous chloride were investigated in a bubble column where the reaction was found to be free from diffusional resistance.The reaction between oxygen and chromous chloride was found to be first order with respect to oxygen and second order with respect to chromous ion. The value of the third order rate constant for 2·0 M HCl solution was found to be 2·7 × 10¹² (cm³/g mole)² sec^?1 at 30°C.The oxidation of titanous chloride was observed to be zero order with respect to titanous ion and first order with respect to oxygen. The value of the first order rate constant was found to be 8·6 × 10^?3 sec^?1. It has been suggested that in this case hydrolysis precedes the oxidation and it is likely that the reaction of oxygen with the hydrolysed product is the rate controlling step.The absorption of oxygen in aqueous ammoniacal cuprous chloride was found to be third order; first order with respect to each species, namely Cu⁺, oxygen and free ammonia. The value of the third order rate constant was found to be 7·5 × 10¹⁰ (cm³/g mole)² sec^?1. The higher value of the rate constant compared to that for oxidation of acidic solutions of curpous chloride indicates that the presence of a complexing agent such as ammonia increases the rate of absorption of oxygen substantially.     

A Kinetic and Mechanistic Study on the Oxidation of Hydroxy Acids by <Emphasis Type="Italic">N</Emphasis>-Bromophthalimide in the Presence of a Micellar System

The kinetics of oxidation of some α-hydroxy acids viz. Tartaric acid (TA) and Malic acid (MA) by N-bromophthalimide (NBP) were studied in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), in perchloric acid medium at 313 K. The oxidation of TA and MA by N-bromophthalimide in the presence of CTAB is faster than in the absence of surfactant. The rate of oxidation of hydroxy acids was found to be in the order: TA > MA. First order kinetics with respect to NBP was observed in the oxidation of both hydroxy acids. The kinetics results indicate that the first order kinetics in hydroxy acids at lower concentrations tends towards a zero order at its higher concentrations. Inverse fractional order in [H⁺] and [phthalimide] were noted throughout its tenfold variation. With a progressive increase in [CTAB], the rate of reaction increased, reaches a maximum value and then constancy in k _Ψ was observed. Variation of [Hg(OAc)₂] and ionic strength (μ) of the medium did not bring about any significant change in the rate of reaction. The applicability of different kinetic models viz. the Piszkiewicz cooperative model, the Raghvan and Srinivasan model, and the Menger–Portnoy model were tested to explain the observed micellar effects. The effect of [CTAB] on the activation parameters was explored to rationalize the micellar effect. The values of rate constants observed at four different temperatures were utilized to calculate the activation parameters. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.

Hydrazine oxidation catalyzed by ruthenium hexacyanoferrate-modified glassy carbon electrode

A ruthenium (III) hexacyanoferrate (Ru(HCF)) film coated on a glassy carbon electrode was explored as an electrocatalyst for hydrazine oxidation. Surface cyclic voltammograms of Ru(HCF) film showed four reversible one-electron redox waves. Two, which corresponded to the redox processes of Ru(III)/Ru(IV) and Fe(II)/Fe(III), were identified to be responsible for the catalytic activity of hydrazine oxidation. Kinetic studies using potential scan rate dependency, Tafel plots, and rotating disk electrode technique found that this catalyzed hydrazine oxidation was a complete four-electron/four-proton process producing N₂, with the rate determining step possibly a one-electron process with a transfer coefficient (α) of ~0.31–0.36. In addition, based on kinetic analysis and findings in the literature, we propose a possible reaction mechanism for catalyzed hydrazine oxidation in order to facilitate further understanding.     

A Strategy for Preparing Star Polymers Containing Metal–Metal Bonds Along the Polymeric Arms Using Click Chemistry

The [(η⁵-C₅H₄(CH₂)₃N₃)Mo(CO)₃]₂ dimer (3) was prepared and used to determine if the Huisgen cycloaddition reaction could be used to synthesize high molecular weight star polymers with metal–metal bonds in the arms. Several different click catalysts were examined. Cp*Ru(PPh₃)₂Cl (Cp* = η⁵-C₅(CH₃)₅) was previously shown to catalyze the formation of metal–metal bond-containing polymers using click chemistry; however, this catalyst underwent a Staudinger reaction with dimer 3 when a model coupling reaction was attempted with phenylacetylene. In order to avoid the Staudinger reaction, Cp*Ru(COD)Cl was used as the catalyst in the reaction of 3 with phenylacetylene, and coupling was observed after 14 h. Synthesis of a star polymer was attempted with 3 and 1,3,5-triethynylbenzene. Instead of coupling, Cp*Ru(COD)Cl reacted with the 1,3,5-triethynylbenzene. A third catalyst, Cu(IMes)Cl (IMes = 1,3-dimesityl-imidazol-2-ylidene) was used to couple 3 with 1,3,5-triethynylbenzene in 48 h. Both a high molecular weight polymer (M _n  = 77,000 g mol^?1) and a tripodal star core (M _n  = 1,800 g mol^?1) were successfully prepared with this catalyst.     

Influence of Catalyst Pretreatments on Propane Oxidation Over Ru/γ-Al2O3

The influence of different treatments (in H₂ or in O₂ at 250 or 600 °C) of alumina supported Ru catalysts on the total oxidation of propane was investigated. Ruthenium catalysts were prepared using RuCl₃ as metal precursor and characterized by H₂ chemisorption, O₂ uptake, BET, XRD and TEM. The presence of chloride on the catalyst surface was found to exert an inhibiting effect on the activity of Ru. The reduced Ru/γ-Al₂O₃ catalysts after partial removing chlorine ions were more active than the same samples oxidized at 250 °C. The higher activity of the reduced Ru/γ-Al₂O₃ catalysts was attributed to the presence of a large amount of active sites on small Ru _x O _y clusters without well defined stoichiometry or on a poorly ordered layer of a ruthenium oxide on the larger Ru particles. The formation of highly dispersed, but in some extent crystallized RuO₂ phase in catalysts oxidized at 250 °C, leads to slightly lower activity of the Ru phase. Strong decline of the activity was found for catalysts oxidized at 600 °C. At this temperature, the Ru particles were completely oxidized to well-crystallized RuO₂ oxide, and the mean crystallite size of the Ru oxide phase was much higher (9–25 nm) than that of after oxidation at 250 °C (~4 nm). The effect of the regeneration treatment in H₂ on the activity of the Ru/γ-Al₂O₃ catalysts was also studied. The active ruthenium species for propane oxidation were discussed based on the catalytic and characterization data both before and after activity tests.     

Characterization of electrochemiluminescence of tris(2,2′-bipyridine)ruthenium(II) with glyphosate as coreactant in aqueous solution

Glyphosate, a phosphorus-containing amino acid type herbicide was used as a coreactant for studying of electrochemiluminescence (ECL) reaction of tris(2,2′-bipyridyl)ruthenium(II) [Ru(bpy)₃²⁺] in an aqueous solution. In a phosphate buffer solution of pH 8, glyphosate itself was known to be electrochemically inactive at glassy carbon electrode, however, it participated in a homogeneous chemical reaction with the electrogenerated Ru(bpy)₃³⁺, and resulted in producing Ru(bpy)₃²⁺ species at the electrode surface. Kinetic and mechanistic information for the catalysis of glyphosate oxidation were evaluated by the steady-state voltammetric measurement with an ultramicroelectrode. The simulated cyclic voltammogram based on this mechanism was in good agreement with that obtained experimentally. ECL reaction of Ru(bpy)₃²⁺/glyphosate system was found to be strongly dependent on the media pH. In a pH region of 5-9, an ECL wave appeared at ca. +1.1 V vs. Ag/AgCl, which was caused by the generation of *Ru(bpy)₃²⁺ via a Ru(bpy)₃³⁺-mediated oxidation of glyphosate. When pH >10, a second ECL wave was observed at ca. +1.35 V vs. Ag/AgCl, which was believed to be associated with a reaction between Ru(bpy)₃³⁺ and the species from direct oxidation of GLYP at a GC electrode surface.     

Electrochemical dissolution of metallic platinum in ionic liquids

The electrochemical dissolution of Pt in several ionic liquids (IL’s) was studied. Different IL’s were tested assessing their potential to dissolve Pt. Dissolution rate and current efficiency were evaluated. The main focus was on Cl containing IL’s: first generation, eutectic based IL’s and second generation IL’s with discrete anions. Pt dissolution only occurred in type 1 eutectic-based IL’s with a max. dissolution rate of 192.2 g m^?2 h^?1 and a max. current efficiency of 99 % for the ZnCl₂-1-ethyl-3-methylimidazolium chloride IL, and 9.090 g m^?2 h^?1 and 96 % for the 1:1 ZnCl₂–choline chloride ionic liquid. The dissolution occurred via the formation of [PtCl _x ] ^y? complexes. To form these complexes, addition of a metal chloride was necessary. Furthermore, an IL with an electrochemical window of 1.5 V, preferably 2.0 V is required to achieve Pt dissolution. The added metal salt needed to have a higher decomposition potential than 1.5 V or should be a Pt salt.