Process for the preparation of rhodium hydrate chloride from rhodium phosphine-containing waste solutions

Abstract

The application provides a method for preparing rhodium chloride hydrate from rhodium-containing phosphine waste liquid, in which the rhodium-containing phosphine waste liquid is subjected to molecular distillation, then is subjected to programmed temperature calcination in an inert gas with carbon three nitrogen four, is subjected to oxidation calcination, is reacted in hydrogen peroxide solution and hydrochloric acid solution, is subjected to ion exchange, and is concentrated and dried to obtain rhodium chloride hydrate. The method greatly improves the rhodium recovery rate, realizes the rhodium recovery rate of greater than or equal to 97.0%, is much higher than traditional direct calcination, and greatly reduces the loss of rhodium.

Description

Technical Field

[0001] This invention belongs to the field of precious metal resource recycling technology, and relates to a method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid. Background Technology

[0002] Rhodium is an expensive platinum group metal, widely used in carbonyl synthesis and automotive exhaust catalysis, and is a key raw material in industrial catalysis. Rhodium-phosphine complex homogeneous catalysts possess advantages such as high activity and good selectivity, and are widely used in carbonyl synthesis reactions. During industrial production, due to poisoning by trace impurities and the accumulation of heavy components such as high-boiling substances, rhodium-phosphine complex homogeneous catalysts gradually deactivate and eventually exit the reaction system, generating organic rhodium-phosphine waste liquid containing triphenylphosphine, triphenylphosphine oxide, and a small amount of rhodium. Because of the high price and scarcity of rhodium, recovering the rhodium contained in rhodium-phosphine waste liquid has significant economic value.

[0003] Currently, the main methods for recovering rhodium from rhodium-containing phosphine waste liquid include hydrometallurgical and pyrometallurgical processes. Hydrometallurgical processes generally involve oxidizing and digesting organic matter with inorganic acids and strong oxidants. This requires a reaction between the organic matter and the strong oxidant, posing significant safety risks. Furthermore, hydrometallurgical processes suffer from low efficiency and incomplete digestion, resulting in low rhodium recovery rates. Pyrometallurgical processes involve burning rhodium-containing waste catalyst liquid to remove complex organic matter and recover rhodium. While highly efficient, direct high-temperature air roasting causes rhodium particles to easily sinter and agglomerate at high temperatures, forming insoluble rhodium oxide. Simultaneously, rhodium oxide readily sublimates and volatilizes, leading to significant loss of the precious metal rhodium. Therefore, rhodium recovery rates are generally below 89%.

[0004] To reduce rhodium entrainment losses during combustion, alkali metal or alkaline earth metal carbonates can be added to rhodium-containing wastewater before incineration, improving rhodium recovery rates, as illustrated in patents CN116622997A, CN1414125A, and CN116445726A. However, the formation of salts from the added compounds during incineration complicates subsequent treatment processes. Alternatively, calcination can be assisted by using sawdust, charcoal additives, or silica to improve rhodium recovery, as illustrated in patents CN111020200A, CN106319202A, and CN102923796A. However, high-temperature sintering often results in the incomplete removal of residual carbon and ash, causing them to tightly encapsulate rhodium active particles; or the presence of porous inorganic materials that adsorb rhodium-containing components leads to incomplete acid leaching, decreased rhodium leaching rate, low rhodium recovery, and poor purity. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid, so as to solve the problem of low rhodium recovery rate in existing rhodium-containing phosphine waste liquid recovery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This application provides a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid, the method comprising: After molecular distillation, the rhodium-containing phosphine waste liquid is mixed with C3N4 and then calcined in an inert gas under programmed temperature rise to obtain a C3N4-modified rhodium-containing solid. The rhodium-containing solid was oxidized and calcined, and then reacted in hydrogen peroxide and hydrochloric acid solutions for 3-5 hours to obtain crude rhodium chlorochloride solution. The crude rhodium chloride solution was subjected to ion exchange, concentration, and drying to obtain hydrated rhodium chloride.

[0007] The present invention has the following beneficial effects: (1) During the high-temperature roasting process of the rhodium-rich mixture obtained by molecular distillation of rhodium-containing phosphine waste liquid and C3N4, the nitrogen-rich sites in C3N4 have a strong coordination adsorption capacity for rhodium ions, which can significantly inhibit the high-temperature volatilization loss of rhodium. At the same time, the nitrogen-containing gas generated by the decomposition of C3N4 can form a local reducing-inert micro-atmosphere around the rhodium-containing solid. This atmosphere can inhibit the high-temperature oxidation of rhodium element produced by the decomposition of the rhodium-rich mixture and inhibit the formation of insoluble rhodium oxide.

[0008] (2) The oxidative roasting of rhodium-containing solids can remove incompletely vaporized residual carbon and other substances generated during the programmed temperature roasting process, and there is no residual ash. At the same time, it avoids the introduction of various impurities or metal ions and will not increase the burden of subsequent processing, achieving no residual carbon and no ash coating of rhodium, rhodium does not agglomerate, and low volatility.

[0009] (3) Compared with traditional roasting with added carbon materials / silicon oxide / sodium carbonate, this application utilizes the in-situ generation of a nitrogen-rich reducing environment by carbon-3 and nitrogen-4 to break the agglomeration of rhodium particles, inhibit the high-temperature oxidation and volatilization of rhodium, and activate the rhodium metal interface, thereby achieving exposed enrichment of rhodium, reducing the roasting temperature, and increasing the leaching rate of rhodium, resulting in a significant increase in the rhodium recovery rate. The rhodium recovery rate is ≥97.0%, which is much higher than that of traditional direct roasting, and significantly reduces the loss of rhodium.

[0010] (4) In this application, C3 and N4 are widely available, have low preparation costs, controllable process energy consumption, and do not require complex special equipment, making them suitable for industrial-scale promotion and application. Detailed Implementation

[0011] This application provides a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid, the method comprising: S01: Rhodium-containing phosphine waste liquid is molecularly distilled, mixed with C3N4, and then calcined in an inert gas at a programmed temperature to obtain C3N4 modified rhodium-containing solid.

[0012] The rhodium-phosphine waste liquid in this application is a waste liquid generated during the hydroformylation reaction of olefins. The composition of the rhodium-phosphine waste liquid includes: 400-900 ppm rhodium, 5.8-6.7% n-butyraldehyde, 1.31-1.50% isobutyraldehyde, 12.9-13.2% triphenylphosphine, 6.2-6.4% triphenylphosphine oxide, and the remainder being heavy components such as butanol, low-carbon hydrocarbons, long-chain aldehydes, long-chain esters, butyraldehyde polymers, other high-boiling-point organic condensates, and hydrocarbons.

[0013] In this application, the rhodium-phosphine-containing waste liquid is first subjected to molecular distillation to remove light solvents and low-molecular-weight condensate polymers. Specifically, the rhodium-phosphine-containing waste liquid is preheated to 45-85°C and then subjected to primary distillation at 130-190°C and 30-110 mbar to remove light solvents such as butyraldehyde, butanol, and low-carbon hydrocarbons, obtaining the primary distillation product. The primary distillation product is then preheated to 55-90°C and subjected to secondary distillation at 180-210°C and 0.05-5 mbar to remove low-molecular-weight condensate polymers, obtaining a rhodium-rich mixture.

[0014] A rhodium-rich mixture is thoroughly mixed with C3Ni4 at a mass ratio of 1:0.5-1:5, and then calcined under programmed temperature rise in an inert gas at a flow rate of 20-200 mL / min to obtain a rhodium-containing solid modified with C3Ni4. The inert gas includes nitrogen, argon, or helium; the programmed temperature rise calcination includes: At room temperature - 275℃, the heating rate is 2-5℃ / min; before heating to 275℃, constant temperature roasting is performed at 50℃ for 60-120min, and then constant temperature roasting is performed at 275℃ for 60-120min. 275-500℃, heating rate is 1-3℃ / min, before heating to 500℃, constant temperature roasting at 50℃ for 30-60min for every 50℃, and constant temperature roasting at 500℃ for 60-120min; The final temperature is 500℃, with a heating rate of 1-2℃ / min, and then calcined at the final temperature for 180-720 min, with the final temperature being 510-600℃.

[0015] C3N4 is a covalent compound composed of carbon and nitrogen, with the molecular formula C3N4. It possesses excellent high-temperature thermal stability and controllable pyrolysis characteristics. During pyrolysis, it continuously releases active nitrogen free radicals, creates a micro-reducing atmosphere, and also exhibits multiple functions including metal coordination activation. During high-temperature calcination of a rhodium-rich mixture and C3N4, the nitrogen-rich sites in C3N4 have a strong coordination adsorption capacity for rhodium ions, which can significantly inhibit the high-temperature volatilization loss of rhodium. The nitrogen-containing gas generated by the decomposition of C3N4 can form a locally reducing-inert micro-atmosphere around the rhodium-containing solid. This atmosphere can inhibit the high-temperature oxidation of elemental rhodium produced by the decomposition of the rhodium-rich mixture and suppress the formation of insoluble rhodium oxide. Furthermore, in this application, the C3N4 is a waste C3N4 photocatalyst or its precursor is one or more of melamine, dicyandiamine, urea, and thiourea.

[0016] S02: The rhodium-containing solid is oxidized and roasted, then reacted in hydrogen peroxide and hydrochloric acid solutions for 3-5 hours to obtain crude rhodium chloride solution.

[0017] The rhodium-containing solid is oxidized and roasted at 550-700℃ for 2-6 hours to remove incompletely vaporized residual carbon and other substances generated during the programmed temperature roasting process. There is no residual ash, and various impurities or metal ions are avoided. This process does not increase the burden of subsequent processing and achieves rhodium-containing concentrate with no residual carbon or ash, no rhodium agglomeration, and low volatility.

[0018] A 31-38 wt% hydrochloric acid solution was added to the rhodium-containing concentrate, and the mixture was heated to 85-115℃. A 30-50 wt% hydrogen peroxide solution was then added dropwise, and the reaction was continued for 3-5 hours. After cooling and filtration, a crude rhodium chlorochloride solution was obtained. The volume-to-mass ratio of the hydrochloric acid solution to the rhodium-containing concentrate was 12-20 mL / g, and the volume ratio of the hydrogen peroxide solution to the hydrochloric acid solution was 0.6-1.1:1.

[0019] S03: The crude rhodium chloride solution is subjected to ion exchange, concentration and drying to obtain hydrated rhodium chloride.

[0020] The crude rhodium chloride solution is subjected to ion exchange using a cation exchange resin to remove impurity ions such as Fe, Ni, and Ca, yielding a refined rhodium chloride solution. The cation exchange resin can be any well-known resin in the art, and the ion exchange conditions can also use conventional parameters, as long as they are effective in removing impurity ions such as Fe, Ni, and Ca. This application does not limit these conditions.

[0021] The rhodium trichloride solution was concentrated by vacuum distillation at 55-75℃ and a vacuum of -0.085 to -0.095 MPa until a crystalline film appeared on the liquid surface, at which point heating was stopped. The concentrate was transferred to a tray and placed in an acid-resistant vacuum oven for vacuum drying at 45-55℃ and a vacuum of -0.085 to -0.095 MPa to further remove free water and excess hydrochloric acid, yielding a dark red or reddish-brown crystalline powder, i.e., hydrated rhodium trichloride.

[0022] The technical solution of the present invention will be further explained and illustrated below through specific embodiments. The composition of the rhodium-phosphine waste liquid includes: rhodium 596 ppm, n-butyraldehyde 6.1%, isobutyraldehyde 1.4%, triphenylphosphine 13.1%, triphenylphosphine oxide 6.3%, and the remainder being butanol, low-carbon hydrocarbons, long-chain aldehydes, long-chain esters, butyraldehyde polymers, other high-boiling-point organic condensation polymers, and heavy hydrocarbon components.

[0023] Example 1 This application provides a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid, the method comprising: S101: 2000g of rhodium-containing phosphine waste liquid was preheated to 85℃ and then subjected to primary distillation at 190℃ and 30mbar to obtain the primary distillation product. The primary distillation product was preheated to 90℃ and then subjected to secondary distillation at 210℃ and 0.1mbar to obtain a rhodium-rich mixture with a rhodium concentration of 1985ppm. 336g of C3Ni4 powder was added to the rhodium-rich mixture and mixed evenly. The mixture was placed in a closed horizontal tube furnace, and nitrogen gas was introduced at a flow rate of 30mL / min. Calcination was carried out using a programmed temperature rise method to obtain a rhodium-containing solid modified with C3Ni4. The programmed temperature calcination includes: room temperature - 275℃, with a heating rate of 4℃ / min; before heating to 275℃, constant temperature calcination is performed at 50℃ for 60 min, followed by constant temperature calcination at 275℃ for 60 min; 275-500℃, with a heating rate of 3℃ / min, before heating to 500℃, constant temperature calcination is performed at 50℃ for 60 min, followed by constant temperature calcination at 500℃ for 60 min; 500℃-510℃, with a heating rate of 1℃ / min, followed by constant temperature calcination at 510℃ for 280 min.

[0024] S102: The rhodium-containing solid was placed in a horizontal tube furnace and oxidized and calcined at 580℃ for 3 hours to obtain a rhodium-containing concentrate. 211 mL of a 37 wt% hydrochloric acid solution was added to the rhodium-containing concentrate, and the mixture was stirred and heated to 90℃. Then, 133 mL of a 30 wt% hydrogen peroxide solution was added dropwise, and the reaction was continued for 3 hours. After the reaction was completed, the mixture was cooled and filtered to obtain a crude rhodium chlorochloride solution.

[0025] S103: After ion exchange with a cation exchange resin, the crude rhodium chloride solution was concentrated by vacuum distillation at 70℃ and -0.095MPa until a crystalline film appeared on the liquid surface, at which point heating was stopped. The concentrate was transferred to a tray and placed in an acid-resistant vacuum oven for vacuum drying at 55℃ and -0.095MPa to obtain a dark red or reddish-brown crystalline powder, i.e., hydrated rhodium trichloride.

[0026] Example 2 This application provides a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid, the method comprising: S201: 2000g of rhodium-containing phosphine waste liquid was preheated to 65℃ and then subjected to primary distillation at 150℃ and 70mbar to obtain the primary distillation product. The primary distillation product was preheated to 70℃ and then subjected to secondary distillation at 195℃ and 1mbar to obtain a rhodium-rich mixture with a rhodium concentration of 1914ppm. 793.6g of C3Ni4 powder was added to the rhodium-rich mixture and mixed evenly. The mixture was placed in a closed horizontal tube furnace, and argon gas was introduced at a flow rate of 50mL / min. Calcination was carried out using a programmed temperature rise to obtain a rhodium-containing solid modified with C3Ni4. The programmed temperature calcination includes: room temperature - 275℃, with a heating rate of 3℃ / min; before heating to 275℃, constant temperature calcination is performed at 50℃ for 60 min, followed by constant temperature calcination at 275℃ for 80 min; 275-500℃, with a heating rate of 2℃ / min, before heating to 500℃, constant temperature calcination is performed at 50℃ for 60 min, followed by constant temperature calcination at 500℃ for 60 min; 500℃-530℃, with a heating rate of 1℃ / min, followed by constant temperature calcination at 530℃ for 390 min.

[0027] S202: A rhodium-containing solid was placed in a horizontal tube furnace and oxidized and calcined at 630°C for 4 hours to obtain a rhodium-containing concentrate. 228 mL of a 37 wt% hydrochloric acid solution was added to the rhodium-containing concentrate, and the mixture was stirred and heated to 95°C. Then, 167 mL of a 50 wt% hydrogen peroxide solution was added dropwise, and the reaction was continued for 4 hours. After the reaction was completed, the solution was cooled and filtered to obtain a crude rhodium chloride solution.

[0028] S203: The crude rhodium chloride solution was ion-exchanged using a cation exchange resin, and then concentrated by vacuum distillation at 65°C and -0.09 MPa until a crystalline film appeared on the liquid surface. Heating was then stopped. The concentrate was transferred to a tray and placed in an acid-resistant vacuum oven for vacuum drying at 50°C and -0.09 MPa to obtain a dark red or reddish-brown crystalline powder, i.e., rhodium trichloride hydrate.

[0029] Example 3 This application provides a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid, the method comprising: S301: 2000g of rhodium-containing phosphine waste liquid was preheated to 45℃ and then subjected to primary distillation at 130℃ and 110mbar to obtain the primary distillation product. The primary distillation product was preheated to 55℃ and then subjected to secondary distillation at 180℃ and 5mbar to obtain a rhodium-rich mixture with a rhodium concentration of 1849ppm. 1662g of C3Ni4 powder was added to the rhodium-rich mixture and mixed evenly. The mixture was then placed in a closed horizontal tube furnace, and helium gas was introduced at a flow rate of 80mL / min. Calcination was carried out using a programmed temperature rise method to obtain a rhodium-containing solid modified with C3Ni4. The programmed temperature calcination includes: room temperature - 275℃, with a heating rate of 5℃ / min; before heating to 275℃, constant temperature calcination is performed at 50℃ for 60 min, followed by constant temperature calcination at 275℃ for 100 min; 275-500℃, with a heating rate of 2℃ / min, before heating to 500℃, constant temperature calcination is performed at 50℃ for 60 min, followed by constant temperature calcination at 500℃ for 100 min; 500℃-550℃, with a heating rate of 1℃ / min, followed by constant temperature calcination at 550℃ for 250 min.

[0030] S302: A rhodium-containing solid was placed in a horizontal tube furnace and oxidized and calcined at 650°C for 5 hours to obtain a rhodium-containing concentrate. 243 mL of a 37 wt% hydrochloric acid solution was added to the rhodium-containing concentrate, and the mixture was stirred and heated to 90°C. Then, 151 mL of a 40 wt% hydrogen peroxide solution was added dropwise, and the reaction was continued for 5 hours. After the reaction was completed, the mixture was cooled and filtered to obtain a crude rhodium chloride solution.

[0031] S303: The crude rhodium chloride solution was ion-exchanged using a cation exchange resin, and then concentrated by vacuum distillation at 55°C and -0.085 MPa until a crystalline film appeared on the liquid surface. Heating was then stopped. The concentrate was transferred to a tray and placed in an acid-resistant vacuum oven, where it was vacuum dried at 45°C and -0.085 MPa to obtain a dark red or reddish-brown crystalline powder, i.e., hydrated rhodium trichloride.

[0032] Comparative Example 1 This application provides a comparative example of a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid, which is the same as in Example 2, except that no C3N4 or other roasting additives are added.

[0033] Comparative Example 2 This application provides a comparative example of a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid. The method is the same as in Example 2, except that C3N4 is replaced with activated carbon.

[0034] Comparative Example 3 This application provides a comparative example of a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid. The method is the same as in Example 2, except that C3N4 is replaced with charcoal powder.

[0035] Comparative Example 4 This application provides a comparative example of a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid. The method is the same as in Example 2, except that C3N4 is replaced with graphite powder.

[0036] Comparative Example 5 This application provides a comparative example of a method for preparing hydrated rhodium chloride from rhodium-phosphine waste liquid. The method is the same as in Example 2, except that C3N4 is replaced with silicon dioxide powder.

[0037] ICP analysis was used to determine the rhodium content in the hydrated rhodium chloride prepared in Examples 1-3, thus identifying the impurity content. Simultaneously, the rhodium recovery rate was calculated for the hydrated rhodium chloride prepared in Examples 1-3 and Comparative Examples 1-5, as shown in Table 1. The formula for calculating the rhodium recovery rate is as follows: Rhodium recovery rate = (mass of rhodium chloride × mass percentage of rhodium in rhodium chloride) / (mass of waste liquid containing rhodium-phosphine complex catalyst × mass percentage of rhodium in waste liquid containing rhodium-phosphine complex catalyst) × 100%.

[0038] Table 1: Impurity Content and Rhodium Recovery Rate As shown in Table 1, the impurity content in the hydrated rhodium chloride prepared using the method provided in this application is less than 0.046%, indicating high purity. Furthermore, compared to Comparative Examples 1-5, the rhodium recovery rate in the method provided in this application reaches 97.1-98.5%, significantly higher than that of Comparative Examples 1-5.

[0039] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid, characterized in that, include: After molecular distillation, the rhodium-containing phosphine waste liquid is mixed with C3N4 and then calcined in an inert gas under programmed temperature rise to obtain a C3N4-modified rhodium-containing solid. The rhodium-containing solid was oxidized and calcined, and then reacted in hydrogen peroxide and hydrochloric acid solutions for 3-5 hours to obtain crude rhodium chlorochloride solution. The crude rhodium chloride solution was subjected to ion exchange, concentration, and drying to obtain hydrated rhodium chloride.

2. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, Molecular distillation of the rhodium-phosphine-containing waste liquid includes: After preheating the rhodium-phosphine waste liquid to 45-85℃, it is subjected to first-stage distillation at 130-190℃ and 30-110mbar to obtain the first-stage distillation product. The primary distillation product is preheated to 55-90°C and then subjected to secondary distillation at 180-210°C and 0.05-5 mbar to obtain a rhodium-rich mixture.

3. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The mass ratio of the rhodium-containing phosphine waste liquid after molecular distillation to the C3Ni4 is 1:0.5-1:

5.

4. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The C3N4 is a waste C3N4 photocatalyst or the precursor of the C3N4 is one or more of melamine, dicyandiamine, urea, and thiourea.

5. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The inert gas includes nitrogen, argon, or helium, with a flow rate of 20-200 mL / min.

6. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The programmed heating and roasting process includes: At room temperature - 275℃, the heating rate is 2-5℃ / min; before heating to 275℃, constant temperature roasting is performed at 50℃ for 60-120min, and then constant temperature roasting is performed at 275℃ for 60-120min. 275-500℃, heating rate is 1-3℃ / min, before heating to 500℃, constant temperature roasting at 50℃ for 30-60min for every 50℃, and constant temperature roasting at 500℃ for 60-120min; The final temperature is 500℃, with a heating rate of 1-2℃ / min, and then calcined at the final temperature for 180-720 min, with the final temperature being 510-600℃.

7. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The oxidation roasting temperature is 550-700℃ and the time is 2-6h.

8. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The volume ratio of the hydrogen peroxide solution to the hydrochloric acid solution is 0.6-1.1:1; the volume ratio of the amount of hydrochloric acid solution added to the volume of the rhodium-containing solid after oxidative roasting is 12-20 mL / g.

9. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The concentrations of the hydrochloric acid solution and the hydrogen peroxide solution are 31-38 wt% and 30-50 wt%, respectively.

10. The method for preparing hydrated rhodium chloride from rhodium-containing phosphine waste liquid according to claim 1, characterized in that, The composition of the rhodium-phosphine waste liquid includes: rhodium 400-900 ppm, n-butyraldehyde 5.8-6.7%, isobutyraldehyde 1.31-1.50%, triphenylphosphine 12.9-13.2%, triphenylphosphine oxide 6.2-6.4%, and the remainder being heavy components.

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