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Synthesis of silver cyanide without poisonous KCN or NaCN
Inorganica Chimica Acta 498 (2019) 119160
Contents lists available at ScienceDirect
Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica
Research paper
Synthesis of silver cyanide without poisonous KCN or NaCN a
a
a
b
Biraj Das , Mukesh Sharma , Manash J. Baruah , Kamala Kanta Borah , Kusum K. Bania a b
a,⁎
T
Department of Chemical Sciences, Tezpur University, Assam 784028, India Department of Chemistry, Mangaldai College, Assam 784125, India
A R T I C LE I N FO
A B S T R A C T
Keywords: Vanadium pentoxide Hydrogen peroxide Acetonitrile Silver cyanide CeCN bond breaking
Highly crystalline silver cyanide (AgCN) was synthesized at room temperature using acetonitrile (CH3CN) as a source of cyanide ion (CN−). The in-situ generation of CN− was assisted by the CeCN bond breaking of CH3CN. The reaction was found to be catalyzed by vanadium pentoxide (V2O5) and hydrogen peroxide (H2O2). The process was very simple and effective one as it was possible to extract the white precipitate of AgCN simply by filtration method. The overnight standing of the whole reaction mixture resulted in the 100% conversion of AgNO3 to AgCN. The most significant aspect of the process was that it did not involve any poisonous cyanide compounds like potassium or sodium cyanide; KCN or NaCN. Further, it also did not lead to the formation of any hazardous waste. The present synthetic approach was thus regarded as an alternative and greener route for preparation of pure AgCN directly from AgNO3.
1. Introduction
cyanidation of silver nitrate using CH3CN by irradiation under highpressure mercury lamp at 300 W [11]. Okabayashi et al. synthesized monomeric AgCN via sputtering reaction of Ag sheet and CH3CN in argon and the monomeric form was characterized using rotational spectroscopy in the gas phase [12]. These known reported procedures for synthesis of AgCN using CH3CN as source of CN− are represented in Scheme 1. In addition to these reported procedures there are certain reports on the coordination complex of silver-cyanide that accounts for the cleavage of CH3CN into CH3OH and CN−. Zhou et al. reported for bridging of CN− in 2D network structure of Ag(I) alkynyl by cleavage of CH3CN [13]. Corma and his co-workers also reported for photochemical cleavage of CeCN bond with multinuclear Ag(I) complex [14]. Guo et al. synthesized silver (I) pyrophosphonate compounds with cyanide by cleavage of CH3CN under solvothermal condition [15]. Heath et al. also found the co-ordination of CN− to silver triazolylidene (trz) species under refluxing condition in CH3CN [16]. The most difficult aspect of the use of CH3CN as a source of CN− is the kinetic inertness and thermodynamic stability of CeCN bond of CH3CN that limits the synthesis of AgCN in presence of CH3CN or other alkyl nitriles. The CeC bond energy in CH3CN is much higher than that of alkanes and makes this molecule highly stable towards any chemical transformation [11,17–19]. Organometallic complexes of transition metals in low oxidation states are known to activate the CeC bond in CH3CN under ambient conditions [20–24]. However, the ability of vanadium oxide in the oxidation or cleavages of CH3CN is very less known in the literature. Probably Brazdil et al. [25] reported for the
Silver cyanide (AgCN) is considered as an important class of silver materials due to the applications in silver electroplating, photography, etc [1,2]. The most common method for preparation of AgCN involves the reaction of silver nitrate (AgNO3) with potassium or sodium cyanide; KCN or NaCN [3]. AgCN is also extracted in large amount in the mining industries by reaction of silver sulfide (Ag2S) with KCN or NaCN [4–6]. However, recent studies have demonstrated that the use of KCN and NaCN led to the death of several people in the mining industries [7]. From the laboratory synthesis point of view, the use of toxic reagents like KCN or NaCN is prohibited in most of the chemical laboratories or can only be used with due permission [8,9]. Therefore, it is reasonable to find out an alternative approach for the synthesis of AgCN that could be commonly practiced under nonhazardous conditions and by avoiding the highly toxic chemicals like KCN or NaCN. Our recent investigation on silver-sulphur-oxido vanadium cluster provided us an alternative route for the development of a process for the preparation of AgCN without using KCN or NaCN [10]. While working with this metal cluster we found the leaching of silver as AgCN in acetonitrile (CH3CN in presence of hydrogen peroxide (H2O2). From our various spectroscopic analyses we propose for the involvement of peroxo-vanadate species in the cleavage of CH3CN or its oxidation resulting in the formation of AgCN as precipitate. This was probably the first report on the synthesis of AgCN with CH3CN under a very mild condition. Formerly, Fan and his co-workers reported for direct
⁎
Corresponding author. E-mail address: [email protected] (K.K. Bania).
https://doi.org/10.1016/j.ica.2019.119160 Received 1 August 2019; Received in revised form 13 September 2019; Accepted 13 September 2019 Available online 14 September 2019 0020-1693/ © 2019 Elsevier B.V. All rights reserved.
Inorganica Chimica Acta 498 (2019) 119160
B. Das, et al.
H2O2. To the resulting yellow solution, 10 mL of CH3CN was added and the reaction mixture was stirred at room temperature for 30–45 min. The colour of the solution at this stage was found to be red. To this red solution, 100 mg of AgNO3 was added slowly and was stirred for another 2 h at the same temperature. At this point the white AgCN particles started to deposit at the bottom of the reaction vessel and got completely settled down on standing the reaction mixture for overnight. A general synthetic approach is represented diagrammatically in Scheme 2. The white and the pure form of AgCN precipitate was easily extracted using Whatman 41 filter paper. Scheme 1. Different reported process for the synthesis of AgCN from CH3CN.
3. Results and discussion The white precipitate so obtained was characterized by XRD and FTIR techniques. In the XRD pattern, sharp and distinct peak corresponding to AgCN was observed at 2θ values of 24, 29.7, 38.2, 49.3, 52.7, 58.5 and 61.8 corresponding to AgCN material (Fig. 1a) [11,15]. No any additional peak for other silver material such as Ag2O or Ag NPs was observed in the XRD pattern. The FT-IR spectrum of white material also represented a sharp band at 2139 cm−1 and a weak band at 2016 cm−1 corresponding to stretching vibration of eC^N bond of AgCN. A sharp signal at 476 cm−1 was attributed to the Ag-C stretching vibration (Fig. 1b) [3,11]. The XRD and FT-IR spectrum of the AgCN isolated by this method was as clean as that of the commercial one. So, this method can be granted for the synthesis of AgCN simply by using V2O5, H2O2, and CH3CN as a source of cyanide. It is pertinent to mention herein that the formation of AgCN using the V2O5 catalyst was dependent on the amount H2O2 and also on the amount of V2O5. It was found that 10 mg of V2O5 and 1.5 mL of H2O2 was sufficient to produce almost 100% AgCN from 100 mg of AgNO3. Increasing the amount of H2O2 lowered the % yield of AgCN. The use of a higher amount of V2O5 did not have any substantial impact on the formation of AgCN or the rate of reaction but it made the isolation process little difficult.
Scheme 2. Synthesis procedure AgCN material from V2O5 via scissoring of CeCN bond of CH3CN.
first time on the gas-phase oxidation of CH3CN using V2O5 as catalyst at a very high temperature. From that report, no advancement has so far been made on the application of V2O5 in the oxidative cleavage of CH3CN. Also, to the best of our knowledge no report is available in the literature on the synthesis of AgCN from AgNO3 using V2O5, H2O2, and CH3CN at room temperature. Very recently, Fan and coworker reported for the synthesis of AuCN using H2O2 and CH3CN under Fenton like condition and also by UV light assisted cleavage of CH3CN [26,27]. Thus, looking at the limitations of the available processes and the need to identify a greener and sustainable technique for AgCN preparation, herein we demonstrate a very simple, effective and non-hazardous route towards AgCN synthesis. 2. Experimental section
4. Conclusion
V2O5 and AgNO3 were purchased from Alfa Aesar and Sigma Aldrich, respectively. HPLC-grade CH3CN was brought from E-Merck and was used in the preparation of AgCN. 30% (w/w) H2O2 was used as received from Merck. The Fourier-transform infrared spectroscopy spectrum (FTIR) was recorded in the mid-IR range of 450–4000 cm−1 in a Frontier-MIR-FIR from Perkin-Elmer. Powder X-ray diffraction (PXRD) measurement was recorded in BRUKER AXS, D8 FOCUS instrument in a low angle measurement from 2θ values of 10–80°.
In conclusion, AgCN was prepared without using NaCN or KCN as a cyaniding agent. The commercially available V2O5 was found to be a highly active catalyst for in situ generation of CN− from CH3CN via CeCN bond cleavage. The reaction happened in presence of 30% H2O2 at room temperature and is considered to be a green oxidizing agent. No such major precaution was required to perform the experiment. However, certain common laboratory precautions were followed to avoid the irritation of eyes and skin that might caused by V2O5 and H2O2. AgNO3 is sometimes toxic if it is used in large amounts, so it should be properly handled while performing the experiment. AgNO3 or the V2O5 should not be contaminated with other metals. It is preferable to use HPLC grade CH3CN to get better yield of AgCN.
2.1. Synthesis of silver cyanide (AgCN) from silver nitrate (AgNO3) In a typical procedure, 10 mg of V2O5 was dissolved in 1.5 mL of
Fig. 1. a) XRD pattern and b) FT-IR spectra of AgCN. 2
Inorganica Chimica Acta 498 (2019) 119160
B. Das, et al.
Declaration of Competing Interest
[5] [6] [7] [8]
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
[9] [10]
Acknowledgements
[11] [12]
K.K.B and MS acknowledges Science and Engineering Research Board, (SERB), Department of Science and Technology (DST), Govt. of India for the financial grant (NO SB/EMEQ-463/2014). B.D thanks UGC-MHRD, Govt. of India for National Fellowship (RGNF-2017-18-SCASS-43132). MS also acknowledge CSIR-HRDG, New Delhi for the SRF fellowship (No 09/796(0094)/19-EMR-I). MJB thanks Department of Science and Technology (DST), Govt. of India for the DST-INSPIRE Fellowship (No. DST/INSPIRE Fellowship/2018/IF180217).
[13] [14] [15] [16] [17] [18] [19] [20]
Appendix A. Supplementary data
[21]
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.ica.2019.119160.
[22] [23] [24]
References
[25] [1] J.N. Gregory, R.R. Hughan, Ind. Eng. Chem. Anal. Ed. 17 (1945) 109–113. [2] T.D. Lazzara, G.R. Bourret, R.B. Lennox, T.G. van de Ven, Chem. Mater. 21 (2009) 2020–2026. [3] G.A. Bowmaker, B.J. Kennedy, J.C. Reid, Inorg. Chem. 37 (1998) 3968–3974. [4] O. Birol, M. Uçurum, Part. Sci. Technol. 34 (2016) 633–638.
[26] [27]
3
G. Senanayake, Hydrometallurgy 81 (2006) 75–85. M. Khalid, F. Larachi, Trans. Nonferrous Met. Soc. China 28 (2018) 542–555. M.S. Reisch, Chem. Eng. News 95 (2017) 18–19. A. Rubo, R. Kellens, J. Reddy, N. Steier, W. Hasenpusch, Alkali Metal Cyanides. Ullmann’s Encyclopedia of Industrial Chemistry, John Wiley and Sons, Inc., 2006. A. Ishii, H. Seno, K. Watanabe-Suzuki, O. Suzuki, T. Kumazawa, Anal. Chem. 70 (1998) 4873–4876. B. Das, M. Sharma, C. Kashyap, A.K. Guha, A. Hazarika, K.K. Bania, Appl. Catal. A 568 (2018) 191–201. S. Zou, R. Li, H. Kobayashi, J. Liu, J. Fan, Chem. Commun. 49 (2013) 1906–1908. T. Okabayashi, E.Y. Okabayashi, F. Koto, T. Ishida, M. Tanimoto, J. Am. Chem. Soc. 131 (2009) 11712–11718. K. Zhou, C. Qin, X.L. Wang, L.K. Yan, K.Z. Shao, Z.M. Su, CrystEngComm 16 (2014) 10376–10379. A. Grirrane, E. Álvarez, J. Albero, H. García, A. Corma, Dalton Trans. 45 (2016) 5444–5450. L.R. Guo, S.S. Bao, Z.Y. Li, L.M. Zheng, Chem. Commun. 20 (2009) 2893–2895. R. Heath, H. Müller-Bunz, M. Albrecht, Chem. Commun. 51 (2015) 8699–8701. Y. Zhu, M. Zhao, W. Lu, L. Li, Z. Shen, Org. Lett. 17 (2015) 2602–2605. M. Zhao, W. Zhang, Z. Shen, J. Org. Chem. 80 (2015) 8868–8873. M. Tobisu, N. Chatani, Chem. Soc. Rev. 37 (2008) 300–307. F.L. Taw, P.S. White, R.G. Bergman, M. Brookhart, J. Am. Chem. Soc. 124 (2002) 4192–4193. F.L. Taw, A.H. Mueller, R.G. Bergman, M.A. Brookhart, J. Am. Chem. Soc. 125 (2003) 9808–9813. T. Lu, X. Zhuang, Y. Li, S. Chen, J. Am. Chem. Soc. 126 (2004) 4760–4761. L.L. Li, L.L. Liu, Z.G. Ren, H.X. Li, Y. Zhang, J.P. Lang, CrystEngComm 11 (2009) 2751–2756. J.J. García, A. Arévalo, N.M. Brunkan, W.D. Jones, Organometallics 23 (2004) 3997–4002. J.F. Brazdil, R.G. Teller, W.A. Marritt, L.C. Glaeser, A.M. Ebner, J. Catal. 100 (1986) 516–519. W. Yi, X. Yan, R. Li, J.Q. Wang, S. Zou, L. Xiao, H. Kobayashi, J. Fan, RSC Adv. 6 (2016) 16448. R. Li, H. Kobayashi, J. Tong, X. Yan, Y. Tang, S. Zou, J. Jin, W. Yi, J. Fan, J. Am. Chem. Soc. 134 (2012) 18286–18294.
Contents lists available at ScienceDirect
Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica
Research paper
Synthesis of silver cyanide without poisonous KCN or NaCN a
a
a
b
Biraj Das , Mukesh Sharma , Manash J. Baruah , Kamala Kanta Borah , Kusum K. Bania a b
a,⁎
T
Department of Chemical Sciences, Tezpur University, Assam 784028, India Department of Chemistry, Mangaldai College, Assam 784125, India
A R T I C LE I N FO
A B S T R A C T
Keywords: Vanadium pentoxide Hydrogen peroxide Acetonitrile Silver cyanide CeCN bond breaking
Highly crystalline silver cyanide (AgCN) was synthesized at room temperature using acetonitrile (CH3CN) as a source of cyanide ion (CN−). The in-situ generation of CN− was assisted by the CeCN bond breaking of CH3CN. The reaction was found to be catalyzed by vanadium pentoxide (V2O5) and hydrogen peroxide (H2O2). The process was very simple and effective one as it was possible to extract the white precipitate of AgCN simply by filtration method. The overnight standing of the whole reaction mixture resulted in the 100% conversion of AgNO3 to AgCN. The most significant aspect of the process was that it did not involve any poisonous cyanide compounds like potassium or sodium cyanide; KCN or NaCN. Further, it also did not lead to the formation of any hazardous waste. The present synthetic approach was thus regarded as an alternative and greener route for preparation of pure AgCN directly from AgNO3.
1. Introduction
cyanidation of silver nitrate using CH3CN by irradiation under highpressure mercury lamp at 300 W [11]. Okabayashi et al. synthesized monomeric AgCN via sputtering reaction of Ag sheet and CH3CN in argon and the monomeric form was characterized using rotational spectroscopy in the gas phase [12]. These known reported procedures for synthesis of AgCN using CH3CN as source of CN− are represented in Scheme 1. In addition to these reported procedures there are certain reports on the coordination complex of silver-cyanide that accounts for the cleavage of CH3CN into CH3OH and CN−. Zhou et al. reported for bridging of CN− in 2D network structure of Ag(I) alkynyl by cleavage of CH3CN [13]. Corma and his co-workers also reported for photochemical cleavage of CeCN bond with multinuclear Ag(I) complex [14]. Guo et al. synthesized silver (I) pyrophosphonate compounds with cyanide by cleavage of CH3CN under solvothermal condition [15]. Heath et al. also found the co-ordination of CN− to silver triazolylidene (trz) species under refluxing condition in CH3CN [16]. The most difficult aspect of the use of CH3CN as a source of CN− is the kinetic inertness and thermodynamic stability of CeCN bond of CH3CN that limits the synthesis of AgCN in presence of CH3CN or other alkyl nitriles. The CeC bond energy in CH3CN is much higher than that of alkanes and makes this molecule highly stable towards any chemical transformation [11,17–19]. Organometallic complexes of transition metals in low oxidation states are known to activate the CeC bond in CH3CN under ambient conditions [20–24]. However, the ability of vanadium oxide in the oxidation or cleavages of CH3CN is very less known in the literature. Probably Brazdil et al. [25] reported for the
Silver cyanide (AgCN) is considered as an important class of silver materials due to the applications in silver electroplating, photography, etc [1,2]. The most common method for preparation of AgCN involves the reaction of silver nitrate (AgNO3) with potassium or sodium cyanide; KCN or NaCN [3]. AgCN is also extracted in large amount in the mining industries by reaction of silver sulfide (Ag2S) with KCN or NaCN [4–6]. However, recent studies have demonstrated that the use of KCN and NaCN led to the death of several people in the mining industries [7]. From the laboratory synthesis point of view, the use of toxic reagents like KCN or NaCN is prohibited in most of the chemical laboratories or can only be used with due permission [8,9]. Therefore, it is reasonable to find out an alternative approach for the synthesis of AgCN that could be commonly practiced under nonhazardous conditions and by avoiding the highly toxic chemicals like KCN or NaCN. Our recent investigation on silver-sulphur-oxido vanadium cluster provided us an alternative route for the development of a process for the preparation of AgCN without using KCN or NaCN [10]. While working with this metal cluster we found the leaching of silver as AgCN in acetonitrile (CH3CN in presence of hydrogen peroxide (H2O2). From our various spectroscopic analyses we propose for the involvement of peroxo-vanadate species in the cleavage of CH3CN or its oxidation resulting in the formation of AgCN as precipitate. This was probably the first report on the synthesis of AgCN with CH3CN under a very mild condition. Formerly, Fan and his co-workers reported for direct
⁎
Corresponding author. E-mail address: [email protected] (K.K. Bania).
https://doi.org/10.1016/j.ica.2019.119160 Received 1 August 2019; Received in revised form 13 September 2019; Accepted 13 September 2019 Available online 14 September 2019 0020-1693/ © 2019 Elsevier B.V. All rights reserved.
Inorganica Chimica Acta 498 (2019) 119160
B. Das, et al.
H2O2. To the resulting yellow solution, 10 mL of CH3CN was added and the reaction mixture was stirred at room temperature for 30–45 min. The colour of the solution at this stage was found to be red. To this red solution, 100 mg of AgNO3 was added slowly and was stirred for another 2 h at the same temperature. At this point the white AgCN particles started to deposit at the bottom of the reaction vessel and got completely settled down on standing the reaction mixture for overnight. A general synthetic approach is represented diagrammatically in Scheme 2. The white and the pure form of AgCN precipitate was easily extracted using Whatman 41 filter paper. Scheme 1. Different reported process for the synthesis of AgCN from CH3CN.
3. Results and discussion The white precipitate so obtained was characterized by XRD and FTIR techniques. In the XRD pattern, sharp and distinct peak corresponding to AgCN was observed at 2θ values of 24, 29.7, 38.2, 49.3, 52.7, 58.5 and 61.8 corresponding to AgCN material (Fig. 1a) [11,15]. No any additional peak for other silver material such as Ag2O or Ag NPs was observed in the XRD pattern. The FT-IR spectrum of white material also represented a sharp band at 2139 cm−1 and a weak band at 2016 cm−1 corresponding to stretching vibration of eC^N bond of AgCN. A sharp signal at 476 cm−1 was attributed to the Ag-C stretching vibration (Fig. 1b) [3,11]. The XRD and FT-IR spectrum of the AgCN isolated by this method was as clean as that of the commercial one. So, this method can be granted for the synthesis of AgCN simply by using V2O5, H2O2, and CH3CN as a source of cyanide. It is pertinent to mention herein that the formation of AgCN using the V2O5 catalyst was dependent on the amount H2O2 and also on the amount of V2O5. It was found that 10 mg of V2O5 and 1.5 mL of H2O2 was sufficient to produce almost 100% AgCN from 100 mg of AgNO3. Increasing the amount of H2O2 lowered the % yield of AgCN. The use of a higher amount of V2O5 did not have any substantial impact on the formation of AgCN or the rate of reaction but it made the isolation process little difficult.
Scheme 2. Synthesis procedure AgCN material from V2O5 via scissoring of CeCN bond of CH3CN.
first time on the gas-phase oxidation of CH3CN using V2O5 as catalyst at a very high temperature. From that report, no advancement has so far been made on the application of V2O5 in the oxidative cleavage of CH3CN. Also, to the best of our knowledge no report is available in the literature on the synthesis of AgCN from AgNO3 using V2O5, H2O2, and CH3CN at room temperature. Very recently, Fan and coworker reported for the synthesis of AuCN using H2O2 and CH3CN under Fenton like condition and also by UV light assisted cleavage of CH3CN [26,27]. Thus, looking at the limitations of the available processes and the need to identify a greener and sustainable technique for AgCN preparation, herein we demonstrate a very simple, effective and non-hazardous route towards AgCN synthesis. 2. Experimental section
4. Conclusion
V2O5 and AgNO3 were purchased from Alfa Aesar and Sigma Aldrich, respectively. HPLC-grade CH3CN was brought from E-Merck and was used in the preparation of AgCN. 30% (w/w) H2O2 was used as received from Merck. The Fourier-transform infrared spectroscopy spectrum (FTIR) was recorded in the mid-IR range of 450–4000 cm−1 in a Frontier-MIR-FIR from Perkin-Elmer. Powder X-ray diffraction (PXRD) measurement was recorded in BRUKER AXS, D8 FOCUS instrument in a low angle measurement from 2θ values of 10–80°.
In conclusion, AgCN was prepared without using NaCN or KCN as a cyaniding agent. The commercially available V2O5 was found to be a highly active catalyst for in situ generation of CN− from CH3CN via CeCN bond cleavage. The reaction happened in presence of 30% H2O2 at room temperature and is considered to be a green oxidizing agent. No such major precaution was required to perform the experiment. However, certain common laboratory precautions were followed to avoid the irritation of eyes and skin that might caused by V2O5 and H2O2. AgNO3 is sometimes toxic if it is used in large amounts, so it should be properly handled while performing the experiment. AgNO3 or the V2O5 should not be contaminated with other metals. It is preferable to use HPLC grade CH3CN to get better yield of AgCN.
2.1. Synthesis of silver cyanide (AgCN) from silver nitrate (AgNO3) In a typical procedure, 10 mg of V2O5 was dissolved in 1.5 mL of
Fig. 1. a) XRD pattern and b) FT-IR spectra of AgCN. 2
Inorganica Chimica Acta 498 (2019) 119160
B. Das, et al.
Declaration of Competing Interest
[5] [6] [7] [8]
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
[9] [10]
Acknowledgements
[11] [12]
K.K.B and MS acknowledges Science and Engineering Research Board, (SERB), Department of Science and Technology (DST), Govt. of India for the financial grant (NO SB/EMEQ-463/2014). B.D thanks UGC-MHRD, Govt. of India for National Fellowship (RGNF-2017-18-SCASS-43132). MS also acknowledge CSIR-HRDG, New Delhi for the SRF fellowship (No 09/796(0094)/19-EMR-I). MJB thanks Department of Science and Technology (DST), Govt. of India for the DST-INSPIRE Fellowship (No. DST/INSPIRE Fellowship/2018/IF180217).
[13] [14] [15] [16] [17] [18] [19] [20]
Appendix A. Supplementary data
[21]
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.ica.2019.119160.
[22] [23] [24]
References
[25] [1] J.N. Gregory, R.R. Hughan, Ind. Eng. Chem. Anal. Ed. 17 (1945) 109–113. [2] T.D. Lazzara, G.R. Bourret, R.B. Lennox, T.G. van de Ven, Chem. Mater. 21 (2009) 2020–2026. [3] G.A. Bowmaker, B.J. Kennedy, J.C. Reid, Inorg. Chem. 37 (1998) 3968–3974. [4] O. Birol, M. Uçurum, Part. Sci. Technol. 34 (2016) 633–638.
[26] [27]
3
G. Senanayake, Hydrometallurgy 81 (2006) 75–85. M. Khalid, F. Larachi, Trans. Nonferrous Met. Soc. China 28 (2018) 542–555. M.S. Reisch, Chem. Eng. News 95 (2017) 18–19. A. Rubo, R. Kellens, J. Reddy, N. Steier, W. Hasenpusch, Alkali Metal Cyanides. Ullmann’s Encyclopedia of Industrial Chemistry, John Wiley and Sons, Inc., 2006. A. Ishii, H. Seno, K. Watanabe-Suzuki, O. Suzuki, T. Kumazawa, Anal. Chem. 70 (1998) 4873–4876. B. Das, M. Sharma, C. Kashyap, A.K. Guha, A. Hazarika, K.K. Bania, Appl. Catal. A 568 (2018) 191–201. S. Zou, R. Li, H. Kobayashi, J. Liu, J. Fan, Chem. Commun. 49 (2013) 1906–1908. T. Okabayashi, E.Y. Okabayashi, F. Koto, T. Ishida, M. Tanimoto, J. Am. Chem. Soc. 131 (2009) 11712–11718. K. Zhou, C. Qin, X.L. Wang, L.K. Yan, K.Z. Shao, Z.M. Su, CrystEngComm 16 (2014) 10376–10379. A. Grirrane, E. Álvarez, J. Albero, H. García, A. Corma, Dalton Trans. 45 (2016) 5444–5450. L.R. Guo, S.S. Bao, Z.Y. Li, L.M. Zheng, Chem. Commun. 20 (2009) 2893–2895. R. Heath, H. Müller-Bunz, M. Albrecht, Chem. Commun. 51 (2015) 8699–8701. Y. Zhu, M. Zhao, W. Lu, L. Li, Z. Shen, Org. Lett. 17 (2015) 2602–2605. M. Zhao, W. Zhang, Z. Shen, J. Org. Chem. 80 (2015) 8868–8873. M. Tobisu, N. Chatani, Chem. Soc. Rev. 37 (2008) 300–307. F.L. Taw, P.S. White, R.G. Bergman, M. Brookhart, J. Am. Chem. Soc. 124 (2002) 4192–4193. F.L. Taw, A.H. Mueller, R.G. Bergman, M.A. Brookhart, J. Am. Chem. Soc. 125 (2003) 9808–9813. T. Lu, X. Zhuang, Y. Li, S. Chen, J. Am. Chem. Soc. 126 (2004) 4760–4761. L.L. Li, L.L. Liu, Z.G. Ren, H.X. Li, Y. Zhang, J.P. Lang, CrystEngComm 11 (2009) 2751–2756. J.J. García, A. Arévalo, N.M. Brunkan, W.D. Jones, Organometallics 23 (2004) 3997–4002. J.F. Brazdil, R.G. Teller, W.A. Marritt, L.C. Glaeser, A.M. Ebner, J. Catal. 100 (1986) 516–519. W. Yi, X. Yan, R. Li, J.Q. Wang, S. Zou, L. Xiao, H. Kobayashi, J. Fan, RSC Adv. 6 (2016) 16448. R. Li, H. Kobayashi, J. Tong, X. Yan, Y. Tang, S. Zou, J. Jin, W. Yi, J. Fan, J. Am. Chem. Soc. 134 (2012) 18286–18294.