In aqueous medium, oxidation of an aromatic alcohol (4-chlorobenzyl alcohol) was carried out in aqueous mixed micellar media under pseudo first order condition by chromic acid at 30 ºC. The micellar microenvironment constituted by anionic SDS and nonionic TX-100 surfactants showed excellent catalytic performance in course of oxidation, individually. In addition to that the nanomicelle produced by combination of SDS and TX-100 was found to be effective microheterogeneous catalyst for the aforementioned oxidation process. Use of two organic precursors, Phen and Bpy, entitled as promoter, made the reaction faster in presence of single micelle and mixed micelle. The fabrication of mixed micelle was confirmed by UV, 1H-NMR and 2D NOESY study. The maximum improvement in reaction kinetic was noticed when SDS/TX-100 surfactants mixture introduced along with Bpy promoter.
Research Article
A synergistic combination of SDS and TX-100 for the catalytic oxidation of an aromatic alcohol in aqueous media
https://doi.org/10.21203/rs.3.rs-2861036/v1
This work is licensed under a CC BY 4.0 License
Journal Publication
published 12 Jul, 2023
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Aromatic alcohol
Oxidation
Nanomicellar catalysis
SDS/TX-100 mixed micelle
CMC lowering
Micelles are generally simple spherical supramolecules, formed by amphiphiles in aqueous medium. Micellar system normally appears as macroscopically homogeneous due to the existence of colloidal size aggregates however in reality they are microheterogeneous system and function as nanoreactors for numerous organic reactions.1 Micelles can accelerate and/or inhibit a chemical reaction relative to the same reaction performed in an aqueous medium. At present aqueous micellar technology are used efficiently to perform many organic reactions in water and the recreation of various organic transformations in aqueous micellar medium has several advantages2–6. The beauty of aqueous micellar media is that it is a green environment, can substitute the hazardous volatile organic solvents that are practically difficult to remove from the organic synthesis.7–11 Noticeably, exercise of mixed micelle in various purposes including emulsification, dispersion, detergency, targeted drug delivery etc.12–18 instead of single one shows very significant performance due to the synergistic effect of constituent surfactants. In our recent works we have investigated the catalytic efficacy of mixed micellar media in oxidation of several organic substrates19–21 along with the physiochemical properties of different mixed micellar composition by different techniques including conductivity, DLS (dynamic light scattering), spectrofluorimetry, etc.22–26 In this report we have accounted the effect of anionic-nonionic mixed micelle on the oxidation kinetic of an aromatic alcohol using the transitional metal oxidant. In addition to, the aggregation behaviour of binary surfactant mixtures has been analyzed following the outcomes of 2D-NOESY.
Chromium(VI) compounds has long been used as potential oxidant for oxidation of alcohols (aliphatic and aromatic) and aldehydes in water or organic medium and has been used for years.27 Use of chromic acid as oxidising agent in aqueous medium is really interesting on account of its distinct aqueous chemistry in H2SO4 medium and generation of reactive short-live intermediate species during the course of electron-transfer reaction. Noticed that Cr(III) is produced at the end of redox transformations, and some report about the usefulness of Cr(III)-picolinate as nutritional supplement encourages to introduce chromium metal as oxidizing agent. Previous works on chromic acid directed oxidation of many organic compounds suggests that, the oxidation rate was further influenced by utilising some N-bases such as 1,10-Phenanthroline, 2,2'-Bipyridine, 2-Picolinic acid, etc.31–36 which was materialized as Cr(III)-N-base complexes at the end of oxidation. These heteroaromatic N-bases compounds are better termed as promoter instead of catalyst.35,36
In our recent work we have manifested the oxidation kinetic of 4-chlorobenzyl alcohol in single micellar medium following pseudo-first order condition.33 Herein, we have uncovered the role of SDS/TX-100 mixed micellar media on the oxidation of same aromatic alcohol by chromic acid at 30°C. The product, 4-chlorobenzaldehyde, is an important intermediate produced in pharmaceutical industry mainly.37–39 The functions of two promoters Bpy and Phen on the oxidation kinetic has been scrutinized in microheterogeneous media. The significant growth of reaction rate was observed when Bpy participated in oxidation mechanism and nanomicellar media (SDS and SDS/TX-100) accommodate the reactant species fructuously during the course of reaction.
2.1. Materials
4-Chlorobenzyl alcohol (> 98.0%, AR, Sigma-Aldrich, USA), Sulphuric acid [H2SO4] (> 97%, AR, Merck, India), potassium dichromate [K2Cr2O7] (> 99.0%, AR, BDH, India), Triton X-100 [TX-100] (98%, AR, HIMEDIA, Maharashtra, India), sodium dodecylsulfate (> 90%, AR, Merck, India), 1, 10-phenanthroline (> 99.0%, AR, Merck, India), 2, 2´-bipyridine (> 98%, AR, Spectrochem, Mumbai, India), chloroform-d (CDCl3) (> 99.0%, AR, Sigma-Aldrich, USA), deuterium oxide (D2O) (> 99.0%, AR, Sigma-Aldrich, USA) were used as received without further purification. All the aliquots were made using double distilled water (specific conductance 2.0 µS cm− 1).
2.2. Instrumentation
Temperature controller attached UV-Vis-2450 (SHIMADZU) spectrophotometer was used to monitor the reaction kinetic. In preparing the reaction solutions sonicator, ultrasonic cleaner (CD 4820), and Sartorius BSA 224S-CW weighing balance were used. The Perkin Elmer Spectrum 2 and Bruker ASCEND 400 MHz spectrometers were used to record the FTIR and 1H-NMR spectrum of the reaction product, respectively.
2.3. Kinetics measurements
The oxidation reaction (in presence of surfactant and/or promoter ) has been performed maintaining the pseudo first order condition. For instance, the substrate (4-chlorobenzyl alcohol) concentration (40×10− 4 mol dm− 3) in large excess (≥ 10-fold) relative to the Cr(VI) (4×10− 4 mol dm− 3) has been taken in aqueous sulphuric acid (0.4 mol dm− 3) medium at 30°C (± 0.1°C). The gradual decrease of absorbance of Cr(VI) with respect to regular time interval at λmax = 440 nm has been recorded with the UV-Vis spectrophotometer to show the progress of the reactions. The slope values of the plots of -ln(Abs)440vs time(t) were used to calculate the rate constant (kobs) values and t1/2 values using the formula (ln2/kobs).
2.4. Product analysis and stoichiometry
In case of uncatalyzed (without surfactant) and unpromoted (without promoter) reaction, the yellow-orange Cr(VI) solution turned into pale greenish-blue coloured solution (Cr(III)) ensured the completion of reaction. After extracting the reaction mixture using diethyl ether followed by evaporation of the solvent, the product was obtained mixed with a slight portion of unreacted solid substrate. Then the product was isolated from the impurity-like substrate by successive treatment with sodium bisulphite solution and solvent extraction.40,41 The recrystallized product and its 2,4-DNP derivative, further recrystallized with ethanol, gave melting points 46°C and 265°C respectively conformed the corresponding carbonyl product. Spectroscopic analysis (IR and 1H-NMR) also confirmed the product is 4-chlorobenzaldehyde.
Spectrophotometric titration of varying concentrations of substrate using Cr(VI) of known concentration in presence of 0.4 mol dm− 3 sulphuric acid gave the following reaction with stoichiometric coefficients. The absorbance values in all cases were taken at 580 nm after 48 hours to get steady measurements.
2.5. Precautions
The alarming toxicity and carcinogenicity of Cr(VI) has limited us the drainage of the same in the experiment. Excessive discharging of surfactants in water bodies also endanger the aquatic lives.42,43 Hence, SDS and TX-100 were recycled and thereby eliminating from the product mixtures (after completion of reaction) through the precipitation with calcium salt and thermal precipitation respectively.44
3.1. UV-Vis spectral analysis and kinetic outcomes
The successive drop in absorbance with respect to equal time interval, provided in Fig. 1, showed the progress of reaction which was performed in absence of surfactant and promoters. The corresponding –ln(Abs) vs time plot (Fig. 2) for every kinetic run help to figure out overall kinetic profile, tabulated in Table 1 and Table 2. The rate constant (kobs) values along with respective half-life (t1/2) were registered in Table 1 and Table 2, in which Table 1 represents the single as well as binary surfactant mediated oxidation kinetics and Table 2 highlights the kinetic parameters for the reaction performed in presence of surfactants and promoters. The tables show that both the single micelles and the mixed micelle have the capability to amplify the reaction rate constant values that indicate the rate enhancement of oxidation process. Noticed, two promoters Phen and Bpy also accelerated the reaction rate. In addition to single micelles the binary mixture of surfactants in combination with promoters enhanced reaction rate significantly, as realized from the histogram (Fig. 3).
Under pseudo-first order condition in presence of large excess of substrate, Cr(VI) ions could surely be reduced to Cr(III) as the reaction proceed. The formation of Cr(III) pale blue coloured solution, was confirmed by the appearance of absorption maxima at 580 nm and 403 nm. (Figure S1). Again, after the completion of the reaction the pale violet colour was observed in presence of Bpy having λmax = 547 nm and pale pink colour was noticed for phen governed oxidation (λmax = 550 nm) towards (Figure S1). Actually, in absence of promoter final reduced product is aqua-Cr(III) species but in presence of promoters, Cr(III)-promoter complex were generated as the reduced species (Figure S1).45,46 Under the experimental condition the single isosbestic point in the UV-Vis spectrum of each reaction suggests the possibility of generation of Cr(IV) and Cr(V) like intermediates with very low concentration (Figure S2).
Table 1. Rate constant (kobs) and half life (t1/2) of oxidation reaction in presence of SDS, TX-100 and SDS/TX-100 mixed micelle.
|
103×Micellar catalyst [mol dm-3] |
104 × kobs[s-1] |
t1/2 [min] |
|
|
SDS |
TX-100 |
||
|
None |
None |
0.48 ± 0.01 |
240.62 |
|
10 20 30 40 50 |
None |
1.85 ± 0.01 2.52 ± 0.01 3.07 ± 0.01 3.51 ± 0.01 3.92 ± 0.02 |
62.43 45.83 37.62 32.90 29.46 |
|
None |
10 20 30 40 50 |
1.14 ± 0.01 1.36 ± 0.01 1.58 ± 0.01 1.81 ± 0.01 2.02 ± 0.01 |
101.31 84.92 73.10 63.81 57.17 |
|
10 |
10 20 30 40 50 |
1.70 ± 0.01 2.20 ± 0.01 2.62 ± 0.02 2.99 ± 0.01 3.38 ± 0.01 |
67.94 52.50 44.08 38.63 34.17 |
|
20 30 40 50 |
10 |
2.83 ± 0.01 3.79 ± 0.01 4.41 ± 0.02 4.93 ± 0.01 |
40.81 30.47 26.19 23.42 |
|
103 × [SDS] mol dm− 3 |
103 × [TX-100] mol dm− 3 |
Promoter |
104 × [Promoter] mol dm− 3 |
104× kobs [s− 1] |
t1/2[min] |
|---|---|---|---|---|---|
|
None |
None |
Phen |
5 10 15 20 25 |
1.01 ± 0.01 2.03 ± 0.01 2.98 ± 0.02 4.05 ± 0.02 4.94 ± 0.01 |
114.35 56.89 38.76 28.52 23.38 |
|
Bpy |
5 10 15 20 25 |
0.84 ± 0.01 1.54 ± 0.03 2.22 ± 0.01 2.98 ± 0.01 3.72 ± 0.02 |
137.50 75.00 52.03 38.76 31.05 |
||
|
10 |
None |
Phen |
5 10 15 20 25 |
2.22 ± 0.01 4.32 ± 0.03 5.87 ± 0.02 9.34 ± 0.01 11.74 ± 0.02 |
52.02 26.73 19.67 12.36 9.83 |
|
Bpy |
5 10 15 20 25 |
23.72 ± 0.01 44.62 ± 0.02 79.55 ± 0.01 106.70 ± 0.03 146.50 ± 0.03 |
4.86 2.58 1.45 1.08 0.79 |
||
|
None |
10 |
Phen |
5 10 15 20 25 |
1.53 ± 0.01 3.92 ± 0.02 5.35 ± 0.01 8.52 ± 0.01 12.68 ± 0.02 |
75.49 29.46 21.59 13.55 9.10 |
|
Bpy |
5 10 15 20 25 |
1.42 ± 0.02 3.42 ± 0.01 4.87 ± 0.01 7.86 ± 0.02 11.58 ± 0.01 |
81.33 33.77 23.71 14.69 9.97 |
||
|
10 |
10 |
Phen |
5 10 15 20 25 |
2.48 ± 0.01 4.86 ± 0.02 6.65 ± 0.01 9.98 ± 0.02 12.44 ± 0.03 |
46.57 23.76 17.36 11.57 9.28 |
|
Bpy |
5 10 15 20 25 |
22.99 ± 0.01 44.32 ± 0.02 78.97 ± 0.03 105.72 ± 0.02 144.16 ± 0.02 |
5.02 2.60 1.46 1.09 0.80 |
4.1. Product analysis
The IR spectrum of the separated product exhibits stretching frequency at 1688.39 cm− 1 corresponding to the C = O bond of aromatic aldehyde group (Figure S3) and the recrystallized 2, 4-DNP derivative of the product displays stretching frequency at 1615 cm− 1 and 3285 cm− 1 pertaining to C = N and N–H bonds, respectively (Figure S4).
The 1H-NMR spectrum (Figure S5) of the product (carried out in CDCl3 solvent) shows a singlet peak with chemical shift value at 9.9 ppm confirms the aldehydic proton. The peaks near 8 and 7.5 ppm in the spectrum indicate two different type of protons, one is ortho to –CHO and another is ortho to –Cl group (Table S1). The comprehensive analysis of FTIR and 1H NMR spectra confirmed the oxidized product which is 4-chlorobenzaldehyde.
4.2. Mechanism of the reaction
The mechanistic pathways of the oxidation can be classified into four different types (i) uncatalysed and unpromoted path, (ii) promoted path, (iii) micellar catalysed path and (iv) micellar catalysed promoted path.
4.2.1. Uncatalysed and unpromoted path
The plausible mechanism of the uncatalysed and unpromoted reaction is already proposed in the previous work.33 Basically, the first step is the formation of neutral chromate ester species between the substrate and chromic acid (H2CrO4). The neutral ester species was then decomposed as governed by H+ ion, this is the r/d step, to give the actual oxidized product and Cr(III) species.47 This is simple mechanistic pathway for the chromic acid directed oxidative transformation of 4-chlorobenzyl alcohol to 4-chlorobenzaldehyde in aqueous media only. It would be interesting to highlight on the reaction kinetic which was affected by micellar media in presence of promoter significantly.
4.2.2 Promoted path
The reaction proceeds with much faster in presence of heteroaromatic N-bases: Phen and Bpy, than the unpromoted one (Table 2). The rate constant values in presence of Phen and Bpy vary in the order kobs(Phen) > kobs(Bpy) (Fig. 4). As already reported that in promoted path the case is quite different due to the formation of Cr(VI)-promoter complexes primarily, which gets reduced to Cr(III)-promoter complexes later. The Cr(VI)-promoter complexes are actual oxidants, recognized as active oxidant species (AO+) (Figure S6).33
The generated active oxidant (AO+) species then undergoes acid catalysed decomposition to form the product. The observed rate constant variation with two promoters can be explained on account of the generation of stable active oxidants (AO+). Herein two promoters (Phen and Bpy) are acts as chelating agents, having two nitrogen donor sites, and fabricates the stable chelated complexes with Cr(VI) centre. The donor sites in 1, 10-Phenanthroline remain in cis configuration with three stable aromatic rings, so rate of formation of active oxidant (AO+) is higher compare to the active oxidant species generated by 2, 2′-Bipyridine. Actually, in stable conformation the N-donor sites of Bpy remains in trans orientation mutually and therefore in order to get converted into s-cis conformation an activation energy barrier must be overcome to formulate such chelated complex or so called active oxidant species. This phenomenon explains the cause of greater rate in case of Phen (Scheme S1 and Scheme S2).
4.2.3 Micellar catalysed path
In presence of two surfactants SDS and TX-100 and in SDS/TX-100 mixed micellar medium the oxidation kinetics were amplified compared to the reaction performed in aqueous medium only (Table 1). Micellar catalysed unpromoted path can be classified into (i) single micelle catalysed and (ii) mixed micelle catalysed path.
4.2.3.1 Single micelle catalysed path
In single micelle catalysed path, both SDS and TX-100 enhance the rate of oxidation and the observed order of rate constant is kobs(SDS) > kobs(TX-100) (Table 1) (Fig. 5). In presence of anionic and nonionic micelle, the schematic representation of interaction between reactant molecules with micelle like surfactant aggregates is shown in Figure S7. In aqueous medium chromic acid is present as HCrO4−, but in micellar media protonation of HCrO4− occurs and neutral H2CrO4 forms, this neutral species can bind with anionic and neutral surfactants through ion–dipole interaction and H-bonding interaction at the stern layer of micellar surface and the reaction proceeds smoothly.47 In micellar media (SDS and TX-100), the hydrophobic part of aromatic alcohol remains in the palisade layer and the polar hydrophilic part remains oriented toward the stern layer of micelle and thereby assists the solubilisation of substrate in aqueous micelle medium.48 In general, aromatic alcohol oxidation depends on two main steps. As mentioned earlier that the formation of neutral chromate ester and subsequent proton (H+) catalysed decomposition of the same in the r/d step take places in aqueous media only (Scheme 1). In anionic SDS micelle, on account of the strong attractive force, the H+ ions can move towards the chromate ester faster than in neutral TX-100 micellar system, results further expediting the oxidation kinetics. Though, the moderate rate enhancement in TX-100 may be attributed to the togetherness of the neutral Cr(VI) species with the micellar aggregates by some supramolecular interaction (ion–dipole interaction and H-bonding).
4.2.3.2 Mixed micelle catalysed path
Above their individual CMC, TX-100 in combination with SDS shows a different λmax (hypochromic shift) from that of TX-100 only indicating a possibility of mixed micelle formation.48 The CMC of mixture of SDS and TX-100 was determined to be 0.15 mM at a constant mole fraction (0.5) of both the surfactants as determined by the conductometry method. The determined CMC value of SDS/TX-100 mixture is higher than CMC of TX-100 (0.24 mM) and much lower than CMC of SDS (8.2 mM) (Table S2, Figure S8).26,49 This study also suggests that discrete single micelle does not exist in the solution mixture rather mixed micelle was produced in the aqueous surfactant mixture (Scheme 2). Earlier works accounted the strong possibility for the interaction of alpha protons of SDS with the phenyl ring of substrate at the close proximity of the mixed micellar form, and the water repelling hydrophobic moiety of SDS is hardly stretched upto the micellar core unlike the coiled hydrophilic moiety of TX-100 in the same aggregation. The appreciable coupling of α-H’s, β-H’s and bulk- H’s of SDS with e-H’s and d-H’s of TX-100 respectively due to their closeness in mixed micelles is also reported earlier.48 For a more illustrative analysis about the relative position of the surfactant molecules in the solution mixture, a 2D NOESY of the 1:1 surfactant mixture solution was recorded (Fig. 6). The peaks in the spectrum elucidates the appreciable coupling of α-H’s, β-H’s and bulk- H’s of SDS with d-H’s and e-H’s of TX-100 respectively due to their closeness in mixed micelles.
The observed rate constant in presence of 1:1 SDS/TX-100 mixed micelle has been found to some extent lower than that observed rate constant in single SDS micelle and higher than that observed rate constant in TX-100 catalysed reaction (Table 1). In addition to that the increase in concentration of a surfactant keeping the other [surfactant] constant above CMC showed significant rate enhancement compared to that of single micelle catalysed reaction (Fig. 7). Noticeably, the kinetics of the reaction augmented further when concentration of TX-100 raised from 0.01 M to 0.05 M keeping [SDS] fixed at 0.01 M. This can be interpreted by considering the formation of micellar aggregation of TX-100 first followed by the decoration of SDS.26 Again at low concentration of SDS, the penetrating space of the substrate inside the TX-100 micelle is occupied by the anionic surfactants and simultaneously a steric reason hinders the same path, reaction rate gets deteriorated. Now, on increasing surfactant concentration of any type corresponding single micellar aggregation may coexist with mixed micelle, which results in rate enhancement.
4.2.4 Micelle catalysed promoted path
From Table 2 we have noticed that the order of reaction rate in promoted path is kobs(Phen) > kobs(Bpy). In micellar catalysed promoted path the mechanism of the reaction is same as that of promoted path. Here also the observed rate constants depend on how easily substrate reacts with active oxidant (AO+) present in aqueous micellar medium to form chromate ester (Scheme S1 and S2). In presence of TX-100 micelle there exists π-π interaction in between the active oxidant species and aromatic sextet of TX-100 and such type of interaction enhances the congregation of active oxidants in stern layer of micelle leading to greater rate of reaction. 1, 10-phenanthroline contains higher number of π-electrons than Bpy, so it shows higher rate of oxidation than Bpy. Hence the rate constant follow the order kobs(Phen) > kobs(Bpy) in TX-100 medium (Table 2). In SDS micellar medium there is no π-π interaction between the active oxidant and SDS, but here strong attractive electrostatic attraction is present between negatively charged SDS and positively charged active oxidant. The active oxidant (AO+) formed by Phen and Bpy are both bipositive in nature. So, considering only attractive force between SDS and active oxidant, Phen and Bpy should show similar rate of oxidation (kobs(Bpy) ≈ kobs(Phen)). In SDS medium besides attractive interaction there is also a possibility of repulsion between negative charge surface of SDS and π electron cloud of active oxidant (AO+). In Phen π electron density is greater than Bpy. So the repulsive interaction is higher in Phen promoted path than Bpy promoted reaction path. So considering only repulsive interaction kobs(Bpy) should be greater than kobs(Phen). Considering both the attractive force and repulsive interaction simultaneously the real order of kobs in SDS micelle is kobs(Bpy) > kobs(Phen) (Table 2). In SDS/TX-100 mixed micelle catalysed path the observed rate constants is kobs(Bpy) > kobs(Phen) (Fig. 8), it can be explained considering above discussed factors and steric factor discussed in the mixed micelle catalysed path.
In this article a green approach of chromic acid directed oxidation kinetics of an aromatic alcohol in presence of single micelle and mixed micelle has been investigated. Combination of micellar catalyst with promoters completes the oxidation of aromatic alcohol almost instantly. In addition to (TX-100 + Phen) and (SDS + Bpy), (SDS + TX-100 + Bpy) were also found to be excellent catalyst. Utilisation of quite low cost mixed micelle may open a new opportunity and supposed to be advantageous for industry.26 In future the effect of mixed micelle on oxidation of various aromatic alcohols and on some physiochemical properties study, for example shape and size of mixed micelle, may lead to some new findings. Besides, such type of kinetics study in variety of binary surfactant media (mixed micelle) like cationic-nonionic, anionic-anionic and cationic-cationic might be of enormous importance for scientific and industrial research.
Acknowledgement
We are thankful to IIT(ISM) Dhanbad for instrumental support.
Consent to publish
We have provided the consent to publish this work.
Competing interests
The authors declare no conflicts of interest regarding this article.
Author contribution
All the authors have accepted responsibility for the entire content of this manuscript and approved submission. AR and BS have designed this work. SC and AA assisted AR to carry out experimental work. KM provided NMR facility. AR and BS wrote the manuscript. RS, BS, and PS modified and revised the whole manuscript.
Funding
There is no funding to mention for this work.
Availability of data and materials
Data of this research work are available on request.
- T. Dwars, E. Paetzold and G. Oehme, Angew. Chem. Int. Ed., 2005, 44, 7174-7199.
- H. Morawetz, Adv. Catal., 1969, 20, 341-371.
- F. Rosati, J. Oelerich and G. Roelfes, Chem. Commun., 2010, 46, 7804-7806.
- K. Bica, P. Gӓrtner, P. J. Gritsch, A. K. Ressmann, C. Schröder and R. Zirbs, Chem. Commun., 2012, 48, 5013-5015.
- B. H. Lipshutz and B. R. Taft, Org. Lett., 2008, 10, 1329-1332.
- J. H. M. Heijnen, V. G. de Bruijn, L. J. P. van den Broeke and J. T. F. Keurentjes, Chem. Eng. Process., 2003, 42, 223-230.
- B. Pawar, V. Padalkar, K. Phatangare, S. Nirmalkar and A. Chaskar, Catal. Sci. Technol., 2011, 1, 1641-1644.
- M. Vashishtha, M. Mishra, S. Undre, M. Singh and D. O. Shah, J. Mol. Catal. A Chem., 2015, 396, 143-154.
- J. N. Israelachvili, J. Mitchell and B. W. Ninham, J. Chem. Soc., Faraday Trans. 2, 1976, 72, 1525-1568.
- A. Acharjee, A. Rakshit, S. Chowdhury, I. Datta, M. K. Barman, M. A. Ali and B. Saha, J. Mol. Liq., 2019, 293, 111475.
- M. N. Khan, Micellar Catalysis, CRC Press Taylor & Francis Group, Boca Raton, 2007.
- M. S. Bakshi and G. J. Kaur, J. Colloid Interface Sci., 2005, 289, 551-559.
- A. Graciaa, M. Benghoulam, G. Marion and J. Lachaise, J. Phys. Chem., 1989, 93, 4167-4173.
- M. Ishikawa, K. Matsumura, K. Esumi and K. Meguro, J. Colloid Interface Sci., 1991, 141, 10-20.
- B. Sohrabi, H. Gharibi, B. Tajik, S. Javadian and M. Hashemianzadeh, J. Phys. Chem. B, 2008, 112, 14869-14876.
- A. Pal and A. Pillania, J. Mol. Liq., 2015, 212, 818-824.
- K. Sharma and S. Chauhan, Colloids Surf. A Physicochem. Eng. Asp., 2014, 453, 78-85.
- A. K. Tiwari and S. K. Saha, Ind. Eng. Chem. Res., 2013, 52, 5895-5905.
- T. Patel, G. Ghosh, V. Aswal and P. Bahadur, Colloid Polym. Sci., 2009, 287, 1175-1181.
- J. P. Mata, J. Disper. Sci. Technol., 2006, 27, 49-54.
- M. E. Haque, A. R. Das, A. K. Rakshit and S. P. Moulik, Langmuir, 1996, 12, 4084-4089.
- H. Zhang and D. L. Paul, J. Colloid Interface Sci., 1997, 186, 264-270.
- T. Z. Wang, S. Z. Mao, X. J. Miao, S. Zhao, J. Y. Yu and Y. R. Du, J. Colloid Interface Sci., 2001, 241, 465-468.
- A. Rajewska, A. K. Islamov and R. F. Bakeeva, J. Phys.: Conf. Ser., 2018, 994, 012015.
- A. Mal, S. Bag, S. Ghosh and S. P. Moulik, Colloids Surf. A Physicochem. Eng. Asp., 2018, 553, 633-644.
- X. Cui, Y. Jiang, C. Yang, X. Lu, H. Chen, S. Mao, M. Liu, H. Yuan, P. Luo and Y. Du, J. Phys. Chem. B, 2010, 114, 7808-7816.
- W. Carruthers and I. Coldham, Modern Methods of Organic Synthesis, 4th edition, Cambridge University Press, 2004.
- R. Saha, R. Nandi and B. Saha, J. Coord. Chem., 2011, 64, 1782-1806.
- C. Togbe, F. Halter, F. Foucher, C. Mounaim-Rousselle and P. Dagaut, Proc. Combust. Inst., 2011, 33, 367-374.
- G. Dayma, C. Togbe and P. Dagaut, Energy Fuels, 2011, 25, 4986-4998.
- A. K. Das, A. Roy and B. Saha, Transit. Met. Chem., 2001, 26, 630-637.
- B. Saha, M. Das and A. K. Das, J. Chem. Res. (S), 2003, 658-661.
- A. Rakshit, S. Chowdhury, A. Acharjee, I. Datta, K. Dome, S. Biswas, S. S. Bhattacharyya and B. Saha, Res. Chem. Intermed., 2020, 46, 2559-2578.
- P. Sar, A. Ghosh, S. Malik and B. Saha, J. Carbohydr. Chem., 2016, 35, 86-105.
- B. Saha, M. Islam and A. K. Das, Inorg. React. Mech., 2006, 6, 141-149.
- A. Ghosh, R. Saha and B. Saha, J. Ind. Eng. Chem., 2014, 20, 345-355.
- M. Budny, J. Włodarczyk, T. Muzioł, M. J. Bosiak and A. Wolan, Tetrahedron Lett., 2017, 58, 4285-4288.
- Y. Todoroki, K. Kobayashi, H. Yoneyama, S. Hiramatsu, M. Jin, B. Watanabe, M. Mizutani and N. Hirai, Bioorg. Med. Chem., 2008, 16, 3141-3152.
- A. Majhi, S. S. Kim and H. S. Kim, Appl. Organomet. Chem., 2008, 22, 466-470.
- J. Clayden, N. Greeves and S. Warren, Organic Chemistry, 2nd edn. Oxford University Press, New York, 2001, pp. 138–140.
- S. Caron, Practical Synthetic Organic Chemistry: Reactions, Principles, and Techniques, 1st edn., Wiley, New Jersey, 2011, pp. 75–76.
- C. L. Yuan, Z. Z. Xu, M. X. Fan, H. Y. Liu, Y. H. Xie and T. Zhu, J. Chem. Pharm. Res., 2014, 6, 2233-2237.
- L. Abu-Ghunmi, M. Badawi and M. Fayyad, J. Surfactant Deterg., 2014, 17, 833-838.
- P. Sar, A. Ghosh, S. Malik, D. Ray, B. Das and B. Saha, J. Ind. Eng. Chem., 2016, 42, 53-62.
- F. A. Cotton, G. Wilkinson, C. A. Murillo and M. Bochmann, Advanced Inorganic Chemistry, 6th edn., Wiley, New York, 1999.
- E. Perez-Benito and E. Rodenas, Langmuir, 1991, 7, 232-237.
- A. K. Das, Coord. Chem. Rev., 2004, 248, 81-99.
- A. Acharjee, A. Rakshit, S. Chowdhury, M. A. Ali, B. Singh and B. Saha, J. Mol. Liq., 2020, 303, 112655.
- R. Saha, A. Ghosh and B. Saha, Chem. Eng. Sci., 2013, 99, 23-27.
No competing interests reported.