Green synthesis of zirconium phosphate by combustion method:
photocatalytic application and microwave-assisted catalytic conversion of aldehyde to nitriles
M SHASHANK1, H S BHOJYA NAIK1,* , J SHASHIKANTH3, AATIKA NIZAM2 and G NAGARAJU3
1Department of Studies and Research in Industrial Chemistry School of Chemical Sciences, Kuvempu University, Shankaragatta 577451, India
2Department of Chemistry, Christ University, Bangalore 560029, India
3Energy Materials Research Laboratory, Department of Chemistry, Siddaganga Institute of Technology, Tumakuru 572 103, India
*Author for correspondence (hsb_naik@rediffmail.com) MS received 27 March 2021; accepted 22 July 2021
Abstract. Water pollution has increased swiftly, especially the dyes from industries that have disturbed aquatic eco-system. Photocatalytic degradation (PCD) is one of the attractive methods to eliminate dyes from industrial effluents.
Zirconium phosphate (ZP) nanoparticles were synthesized by combustion method using zirconyl nitrate and phosphorous pentoxide as precursors. The obtained ZP was characterized by powder X-ray diffractogram, Fourier transform infrared, scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, photolumines- cence spectroscopy, Brunauer–Emmett–Teller surface area. PCD was carried out using methylene blue as a model pollutant in aqueous medium in the presence of UV light irradiation with different concentrations of dye, catalyst and pH.
Higher degradation efficiency was observed in basic medium. ZP is employed as a catalyst to form nitrides from aldehydes using different solvents with different aldehydes.
Keywords. Combustion; photocatalytic degradation; aldehydes; nitriles.
1. Introduction
The existence of pollutants in water possesses huge ecological problems to all living creatures [1]. Synthetic organic compounds including dyes produced from various industries, such as pigment, cosmetics, paper, plastic, skin, leather, photography [2], food and pharmaceuticals, etc., are the major causes for pollution [3,4]. The aromatic structure of dyes makes them more resistant to degradation in natural environmental conditions [5]. Since pollution has been increased largely, the international environmental standard is becoming rigid to reduce pollution (ISO 14001, October 1996), and the technology to remove/diminish dyes has been developing. A few of such methods are adsorption [6], biodegradation [7], chemical methods [8], etc.
In recent years, we are facing challenges in the inefficient reduction of pollutants in the environment. Photocatalytic degradation (PCD) is one of the prominent ways to reduce pollutants in water [9], since the major by-products are CO2 and H2O [10,11]. The proposed article concentrates on PCD of methylthioninium chloride (C16H18N3SCl), commonly called as methylene blue (MB), which is used in the
applications like dying wool, cotton, cloths, etc. MB can cause burning sensation in the eye, which can lead to damage in the eye. If MB enters the human body it may lead to mental disorder, nausea, methemoglobinemia, etc. [12–14]. Syn- thesis of nanoparticles (NPs) from naturally available plant extract instead of using laboratory available chemicals, which produces harmful by–products, is considered as a green synthesis [15]. Various reports are available for the synthesis of metal oxide NPs using plant extracts as a fuel [16].
Zirconium phosphate (ZP) shows good cation-exchanger [17] and proton conductor [18]. It shows unique properties such as fluorescence [19], chiral or molecular recognition and also a good catalyst [20]. Many methods have been applied for the synthesis of ZP NPs, such as hydrothermal [21], sol–gel method [18], co-precipitation [22], ionothermal, etc. ZP has been stud- ied in diverse applications, such as insulin nano encapsulation for oral delivery, ion exchanger, Al3?potentiometric sensor, dehydration of fructose and insulin [23] etc. The photocatalytic activity of ZP has not been studied extensively.
The nitrile is an exceptionally helpful material for organic chemists and it may be promptly changed over into different heterocycles and functional groups, for example, https://doi.org/10.1007/s12034-021-02555-7
amines, amides, carboxylic acids, ketones, esters, etc. [24].
Nitriles are also significant capital materials in synthetic and pharmaceutical ventures, and have been broadly utilized in the generation of useful compounds, for example, polymers, agrochemicals, pharmaceuticals and colours [25]. Appro- priately planned organ nitrile subsidiaries are broadly archived as bioactive molecules (figure 1) [26].
The most well-known way to study the formulation of nitriles includes substitution reactions of organic halides with nitrile group. Extremely functional and modest course for the synthesis of nitriles makes use of poisonous cyanide, which demonstrates risk on scale up. Then again, some natural cyanide sources have been investigated with extraordinary result. Traditional techniques for nitrile for- mulation are Sandmeyer reaction [27], ammoxidation of aldehydes [28], Kolbe nitrile synthesis, hydrocyanation of alkenes [29] and Rosenmund–von Braun reaction [30].
As opposed to consolidating the nitrile’s usefulness straight forwardly, different nitrogen-containing function- alities can be changed over into nitriles. Alternative strategies for the synthesis of these compounds include the one-step change of aldehydes into nitriles, which is a standout amongst the most productive and cleanest paths for this change [31]. Through the previous decades, studies on formulation of nitriles from aldehydes have gained much consideration. A few techniques are accounted for in the literature, which incorporate utilizing trichloroisocyanuric acid (TCCA) [32], dry alumina [33], FeCl3[34], graphite, zinc oxide (ZnO) [35], Ag NPs [36], [BMIM(SO3H)][OTf]
(BMIM1-butyl-3-methyl-imidazolium) [37], acetohy- droxamic acid/Bi(OTf)3[38], CuO NPs [39], CeCl37H2O/
KI/H2O2, triflic acid [40] and electrochemical strategies [41].
In any case, the prior strategies experienced at least one of the accompanying disadvantages: the utilization of strong acids or bases or oxidants, delayed reaction time, low yield, prerequisite of overabundance reagents/catalysts, arduous work up systems, or severe reaction conditions.
Recently, solid acid, which assume a noteworthy job in the improvement of clean advancements, has fascinated expanding interest and effectively utilized in an assortment of reactions. As contrasted with conventional liquid acids, solid acid has numerous preferences, for example, produc- tivity, operational straight forwardness, simple recyclabil- ity, noncorrosive nature and ecological amiability [42].
Microwave-helped synthesis has pulled in significant consideration off lately. This unusual microwave (MW) energy has been utilized for warming food for half a century and is currently being used for a range of synthetic appli- cations as well as organic synthesis [43]. Utilizing micro- wave in synthesis can drastically lessen reaction time and furthermore expand yield, selectivity and purity of the product most of the time and permits the reaction to con- tinue under solvent-free conditions with most extreme efficiency [39,44].
The aim of this study is to synthesize ZP by a simple and low-cost combustion method, usingTamarindus indicaas a novel fuel for the photocatalytic application with MB dye degradation with diverse experimental conditions. In addi- tion, we report microwave-assisted ZP catalysed conversion of aldehyde to nitriles using hydroxylamine hydrochloride.
This route was chosen for its simplicity, low toxicity and highly compact reaction time.
2. Experimental
2.1 Materials used
All chemicals used were of analytical grade and proceeded without further purification. Zirconyl nitrate [ZrO(NO3)2x H2O] was supplied by S D Fine Chemicals Limited, India, and phosphorous pentoxide (P2O5) was supplied by Fisher Scientific, India.
Preparation of tamarind seed powder: Locally (Tumakuru) available tamarind seeds were collected and washed with water, and dried in the presence of sunlight until it gets completely dry. Then the dried seeds were ground well until a fine powder was formed. Tamarind seeds mainly consists of carbohydrates (50–57%), proteins (13–26%), sugar (15–25%), oil (5–15%), crude fibre (7–8%), tannin, ash content and moisture.
2.2 Synthesis method
Zirconyl nitrate [ZrO(NH3)2] (230 mg) and phosphorous pentoxide (P2O5) (140 mg) are taken in a clean and dried crucible, followed by the addition of tamarind seeds powder (200 mg). A quantity of 10 ml of deionized water was added, and stirred for few minutes with a magnetic stirrer to get the homogeneous mixture. Then the crucible is placed in a pre-heated muffle furnace at*5008C, erupt-type reaction Figure 1. Effective biologically active nitrile molecules.
takes place within 7–10 min. After the combustion, the crucible was left in a furnace to reach the room temperature.
Nanosized ZP powder was forged.
2.3 Characterization
Powder X-ray diffractogram (XRD) was recorded on a Rigaku Smart Lab X-ray diffractometer (Cu-Ka,k= 1.5406 A˚ ). Fourier transform infrared (FT-IR) was examined using Shimadzu FT-IR-84000s spectrophotometer. Surface area and pore volume was studied by Brunauer–Emmett–Teller using Bellsorp Max, Japan. The morphology was examined by scanning electron microscopy (SEM) on JOEL NeoS- cope JCM-6000PLUS. Transmission electron microscopy (TEM) analysis was examined by JEOL/JEM 2100. UV DRS was conducted using LABINDIA Technologies UV 3092 spectrophotometer. Agilent technology-Cary-60
Eclipse spectrophotometer was used for luminescence studies. Raman spectroscopy was examined by Horibal- abram HR 800. 1H NMR was done using Bruker spec- trometer at 400 MHz grade and delta values are expressed in ppm. GC-MS was done in Shimadzu GCMS-QP2010SE for the identification of the synthesized nitriles obtained.
10 20 30 40 50 60
200 400 600 800 1000 1200
(430)
(332)
(321)
Intensity
2 Theta (Degree)
(111) (200) (210) (211) (220) (311) (024)(331) (422) (511)
(222) (023) (400) (410)
Figure 2. XRD pattern of ZP NPs.
Figure 3. FT-IR spectrum of ZP NPs.
Figure 4. Nitrogen adsorption–desorption isotherm with porous size distribution curve of ZP NPs.
Figure 5. (a, b) SEM images, (c) EDX spectrum, (d) TEM images, (e) HR-TEM and (f) SEAD pattern of ZP NPs.
2.4 Measurement of photocatalytic activity
The photocatalytic activity of ZP NPs was evaluated by the degradation MB at room temperature. The photocat- alytic reaction was carried-out using Hebber Scientific UV-Visible reactor. It contains 100 ml of 8 quartz tube placed around the source in a circular way. Blue Pho- toreactor, UV source of 250 W, is used for the photocat- alytic experiment. Before irradiation, pollutant sample was stirred by air bubbles for 30 min in dark conditions to gain adsorption-dispersion equilibrium of the dye. During the PCD, approximately 2 ml of the suspension was col- lected at a 30-min time interval and centrifuged for the removal of particles. The percentage of MB degraded with respect to time was measured by UV-Visible spectrometer.
The efficiency of PCD was calculated using the formula, Percentage of degradation¼ ½ðCiCfÞ=Ci 100%;
Figure 6. UV–visible DRS and energy bandgap of ZP NPs. ð1Þ
Figure 7. (a) Excitation, (b) emission peak and (c) CIE diagram of ZP NPs.
whereCiis initial concentration of MB at timet= 0,Cfthe concentration between the selected time interval.
2.5 General procedure for synthesis of nitrile
A mixture of aldehyde (2 mmol), NH2OHHCl (2 mmol), DCM (2.5 ml) and 6 mg of ZrPO4 was taken in a 15 ml pyrex cylindrical tube, homogenized and was irradiated with microwave at 250 W. Post-irradiation of reaction mixture for 2–3 min, cooled to room temperature and extracted with ethyl acetate (5 ml). The solvent was evap- orated using vacuum and organic layer was dried over anhydrous sodium sulphate. The crude product was refined using a short column silica gel, using petroleum ether and ethyl acetate as eluent to procure the pure product.
3. Results and discussion
3.1 X-ray diffraction (XRD)
XRD pattern, in figure 2, of the synthesized NPs shows cubic phase with space group Pa-3, space group no. 205.
The diffraction patterns of nanosized particles are in good agreement with the JCPDS 01-085-0896, with lattice parametersa = b = c= 8.25 A˚ ,a=b=c=908and no other impurity peaks were observed. The average crystallite sizes of ZP NPs were calculated using Debye-Scherrer’s equation.
D¼ ðkkÞ=bcosh; ð2Þ
where k is crystallite shape constant (0.89), k the wave- length of corresponding Cu-Ka(1.5406 A˚ ),bthe full-width and half-maximum andhthe glancing angle. From equation (2), the average size of the synthesized ZP NPs is found to
be 66 nm. Table
1.ComparisonofphotocatalyticactivityofZPNPswithreferentsample. Sl.NoMaterialSynthesismethodNameoftheorganicdyeLightsourceDegradation(%)attimeReference 1ZirconiumphosphateReflexmethodMethyleneblueLow-pressuremercurylampUV(15W,Philips)60%for120min[49] 2ZrP-TiO2SolvothermalapproachMethylorange20Wultravioletlamp90%for130min[50] 3ZP-TiO2SolvothermalapproachMethyleneblueNaturalsunlight68%for300min[51] 4Zirconiumphosphatesol–geltechniqueCongoredNaturalsolarlight50%for60min[52] 5ZirconiumphosphateSolvothermalapproachRhodamineBHalogenlamp5%for30min[53] 6ZirconiumphosphateCombustionmethodMethyleneblueTungstenbulb98%for150minPresentwork Figure 8. Raman spectrum of ZP NPs.
(a) (b)
(c)
0 20 40 60 80 100 120 140
0 20 40 60 80 100
Degradation(%)
Time(min) Time(min)
Time(min)
20 mg 15 mg 10 mg 5 mg
0 20 40 60 80 100 120 140
0 20 40 60 80 100
Degradation(%) 5 ppm10 ppm
15 ppm 20 ppm
0 20 40 60 80 100 120 140
0 20 40 60 80 100
Degradation(%)
2 pH 4 pH 6 pH 8 pH 10 pH 12 pH
Figure 9. Photocatalytic degradation of MB with different (a) catalytic loads, (b) initial concentration and (c) varying pH conditions.
Figure 10. (a) Rate constant of MB in the presence of ZP NPs. (b) Photoluminescence spectrum of 7-hydroxyl coumarin generated.
3.2 FT-IR analysis
The FT-IR spectrum of ZP NPs is shown in figure 3. The band at 1108 cm–1 corresponds to P = 0 asymmetric stretching vibration. An adsorption band was identified at 545 cm–1 due to asymmetric stretching vibration of Zr-O [23,45,46]. The peaks at 3432 and 1622 cm–1 come from O–H stretching and bending vibration of water. The band at 2925 cm–1corresponds to C–H stretching, arising from the presence of fuel.
3.3 Brunauer–Emmett–Teller
Surface area is one of the major factors for the degradation of organic dyes. The pore size and the specific surface area distribution (BJH) were studied by N2 adsorption–desorp- tion isotherm experiment of synthesized NPs. Brunauer–
Emmett–Teller surface area of ZP NPs is found to be 8.018 m2g–1, the total pore volume is 0.019607 cm3g–1and mean pore diameter was found to be 9.7817 nm, which are shown in figure 4. From pore size distribution pattern, we can conclude that ZP NPs have a good porosity.
3.4 Morphological analysis
SEM is used to investigate the morphology of the sample.
Figure 5a and b shows agglomerated structure. Energy dispersive X-ray analysis pattern, in figure 5c of ZP NPs shows the presence of zirconium, phosphorous and oxygen.
TEM images, figure5d, show the structure similar to honey comb with uneven distribution. HR-TEM image, figure5e, shows the d-spacing of 0.25 nm, which corresponds to
(311). Selected-area electron diffraction pattern, figure 5f, shows good crystallinity, which is in agreement with the XRD pattern.
3.5 UV-DRS
Kubelka–Munk equation was adopted to calculate energy bandgap of ZP NPs (figure 6) [47].
F Rð 1Þ ¼ð1R1Þ2=2R1; ð3Þ
whereRis the reflection co-efficient of sample.
By plotting the graph of [F(R)E]1/2 vs. energy bandgap, energy bandgap of ZP NPs was found to be*4.2 eV.
3.6 Photoluminescence spectrum
Photocatalytic efficiency of a catalyst can also be predicted using photoluminescence spectroscopy. Figure7a shows the photoluminescence emission spectrum of ZP NPs by exciting at 277 nm. Figure7b shows violet emission at 386 nm [19,48]. CIE 1931 chromaticity diagram of ZP NPs (figure7c) shows blue emission.
3.7 Raman spectrum
Raman spectrum of ZP NPs (figure 8) shows peaks at 81 and 1356 cm–1, which attribute to P–O bonds and the peak at 1603 cm–1 symmetric stretching of the PO4 unit. The Table 2. Reaction optimization with different solvents.
Entry Solvent Catalyst Yield (%)
1 Ethyl acetate ZrPO4 70
2 Dichloromethane ZrPO4 98
3 Hexane ZrPO4 57
4 Acetone ZrPO4 40
5 Ethanol ZrPO4 42
6 Water ZrPO4 30
Table 3. Catalyst load optimization.
Entry Catalyst load (g) Yield (%)
1 0.006 98
2 0.036 98
3 0.216 98
Scheme 1. Microwave-assisted catalytic conversion of aldehyde to nitriles.
Figure 11. Reusability of catalyst.
peaks at lower frequencies are related to the long-range order of the system. These peaks are attributed to vibration stretching and bending between elements.
3.8 Photo-catalytic degradation
The combustion-assisted ZP NPs photocatalytic activity has been degraded under tungsten light source. MB was con- sidered as organic pollutants for degradation using ZP NPs.
In the absence of light, there is no degradation observed.
The PCD was conducted at different parameters like a variation in the amount of catalyst, different concentrations of dye and different pH conditions. The comparative study of degradation of dyes in the presence of ZP NPs is shown in table1.
3.8a Effect of catalytic dosage: The effect of catalytic loading is studied by varying the amount of ZP NPs by keeping the concentration of MB constant at 5 ppm/100 ml of MB. From figure 9a, increase in the amount of catalyst increases the rate of degradation due to increase in active sites.
3.8b Effect of initial dye concentration: The increase of dye concentration decreases the rate of PCD (figure 9b).
This is because, as the concentration of dye increases, more number of dye molecules are adsorbed on the surface of the catalyst. This leads to decrease in OH• radical production on the surface of NPs. The path length of photons entering the aqueous solution reduces as initial dye concentration increased, reducing the amount of photons reaching the active material, which reduces the rate of degradation [54].
3.8c Effect of pH: The effect of pH is one of the important factors that alter the PCD greatly. Effect of pH is studied by varying the pH from acidic to basic medium
using 5 ppm/100 ml MB with 10 mg of ZP NPs, as shown in figure9c. It indicates that photocatalytic activity is more in basic medium [55]. In acidic medium, the surface of ZP becomes positively charged and the attraction between dye and NPs decreased with low degradation capacity. Increase in the pH value of basic medium increases the degradation rate. In basic condition, the surface of NPs becomes negatively charged, which attract the dye leading to increase in degradation because of the electrostatic interaction of negatively charged ZP surface and cationic MB [56]. In basic condition, availability of OH• is higher from OH–ions rather than H2O, which helps in height rate of PCD of MB. Further, the direct oxidation and reduction between the catalyst and MB dye in basic pH is due to adsorption of MB onto catalyst. Hence, the photocatalytic dye degradation at acidic pH is low compared to basic pH, and similar results of PCD were found for ZP, as shown in the equation below [57].
hVBþþOH !OH ð4Þ
Methylene blueþhVBþ!oxidation products ð5Þ Methylene blueþeCB!reduction products ð6Þ
3.8d Possible mechanism for dye degradation: During PCD, the energy absorbed by a semiconductor should be greater than or equal to its bandgap. The electrons (e–) that gets exited from valence band (VB) to conduction band (CB) causes e–and holes as indicated in equation (7).
ZPþhm!ZPðeðCBÞ þhþðVBÞ ð7Þ The holes generated in VB react with water to create OH• radical.
H2Oþ!hþðVBÞOHþHþ ð8Þ
The–OH radical created on the surface of ZP is oxidizing agent. It attacks the closest dye and causes them to convert to an extent depending the stability. The e–in the CB is Table 4. Microwave-assisted catalytic conversion to nitriles.
Entry Substrate Product m/z Yield (%) IR (cm–1)
1 Benzaldehyde Benzonitrile 103.04 98 2231
2 m-Nitrobenzaldehyde 3-Nitrobenzonitrile 148.03 83 2238
3 o-Nitrobenzaldehyde 2-Nitrobenzonitrile 148.03 78 2239
4 o-Chlorobenzaldehyde 2-Chlorobenzonitrile 137.00 89 2227
5 p-Chlorobenzaldehyde 4-Chlorobenzonitrile 137.00 95 2227
6 p-Hydroxybenzaldehyde 4-Hydroxybenzonitrile 119.04 99 2232
7 o-Hydroxybenzaldehyde 2-Hydroxybenzonitrile 119.04 90 2230
8 Furfuraldehyde Furan-2-carbonitrile 93.02 78 2225
9 p-Fluorobenzaldehyde 4-Fluorobenzonitrile 121.03 85 2233
10 p-Bromobenzaldehyde 4-Bromobenzonitrile 180.95 86 2221
11 o-Bromobenzaldehyde 2-Bromobenzonitrile 180.95 80 2221
12 Methoxy benzaldehyde 4-Methoxybenzonitrile 133.05 72 2227
13 2-Naphthaldehyde 2-Naphthonitrile 153.06 92 2231
14 Vanillin 4-Hydroxy-3-methoxybenzonitrile 149.05 88 2228
picked up by oxygen to generate anionic superoxide radical (O2–•).
O2þeðCBÞ !O2 ð9Þ
The O2–and–OH radicals created attacks the dye, which reduces to form CO2and H2O as major products.
3.8e Kinetics of PCD: From previous studies [58,59], PCD of dyes can be regarded to pseudo-first-order reaction.
Langmuir–Hinshelwood model was applied for degradation kinetics of MB dye, ln(Co/Ct) = kt, whereCois the initial concentration of dye when time is zero. Ct is a concentration in a selected time interval and k the rate constant. The rate constant, from figure10a, of ZP NPs was found to be 2.4 910–2min–1.
3.8f Detection of OH radicals: In PCD, hydroxyl radicals (•OH) have an important role as reactive species.
It was studied using coumarin. Coumarin reacts with •OH giving 7-hydroxyl coumarin and it is measured by photoluminescence technique. In this process, 20 mg of ZP NPs was dispersed in 100 ml of 0.5 mM aqueous coumarin solution photoreactor. The solution was bubbled for 30 min before irradiation. For every 30 min, 2 ml solution was taken out and photoluminescence intensity was measured. Figure 10b shows OH radical intensity with different time of irradiations.
3.9 Formulation studies
3.9a Synthesis of nitriles: The pilot reaction was done using benzaldehyde (2 mmol) and hydroxylamine hydrochloride (2 mmol) to make the reaction conditions optimal. The reaction was initially done with and without the catalyst to check the importance of the catalyst on heating at 70C. Following, the reaction was worked with various solvents (3 ml) in the presence of the catalyst to monitor the effect on yield (table2). It was noted that when only catalyst was used the yield was 68%, while with solvent and catalyst it reached a maximum yield of 98%.
Subsequently, load of the catalyst was changed to monitor the effect of catalyst load on the yield and it was found that it did not change with increase in catalyst load (table 3).
Further, for time optimization, reaction was stopped at every 30 s, the yield was checked and found that it reached maximum at 3 min. A succession of nitrile compounds was synthesized using aldehydes and hydroxylamine using catalyst and microwave assistance (scheme 1).
The catalyst reusability was done as per the entry 1 in table 2, under equal conditions. The catalyst was retrieved using filtration of the reaction mixture, was washed with water and ethyl acetate and dried at 808C for 1–2 h. The yield was calculated for each cycle by taking into the consideration the starting material and the product obtained Table5.NMRresultsofmicrowave-assistedcatalyticconversiontonitriles. EntrySubstrateProductNMR 1BenzaldehydeBenzonitrile1HNMR(CDCl3)d=7.62–7.80(3H,m),7.48(2H,d) 2m-Nitrobenzaldehyde3-Nitrobenzonitrile1 HNMR(CDCl3)d=8.54–8.51(1H,m),8.42(1H,s)8.31–8.33(1H,m),7.88–7.90(1H,m) 3o-Nitrobenzaldehyde2-Nitrobenzonitrile1 HNMR(CDCl3)d=8.40–8.42(1H,m),7.90–7.96(2H,m)7.39–7.41(1H,m) 4o-Chlorobenzaldehyde2-Chlorobenzonitrile1 HNMR(CDCl3)d=7.69–7.67(1H,m),7.56–7.52(2H,m),7.40–7.38(1H,m) 5p-Chlorobenzaldehyde4-Chlorobenzonitrile1 HNMR(CDCl3)d=7.63–7.60(2H,m),7.50–7.48(2H,m) 6p-Hydroxybenzaldehyde4-Hydroxybenzonitrile7.70–7.68(2H,m),7.14–7.12(2H,m),5.34(1H,s) 7o-Hydroxybenzaldehyde2-Hydroxybenzonitrile7.55–7.47(2H,m),7.13–7.18(2H,m)5.35(1H,s) 8FurfuraldehydeFuran-2-carbonitrile1 HNMR(CDCl3)d=8.03–8.05(1H,m),7.15-7.17(1H,d),6.82-6.84(1H,m) 9p-Fluorobenzaldehyde4-Fluorobenzonitrile1 HNMR(CDCl3)d=7.70–7.68(2H,m),7.20–7.18(2H,m) 10p-Bromobenzaldehyde4-Bromobenzonitrile1 HNMR(CDCl3)d=7.68–7.65(2H,m),7.50–7.52(2H,m) 11o-Bromobenzaldehyde2-Bromobenzonitrile1 HNMR(CDCl3)d=7.78–7.80(1H,m),7.61–7.54(3H,m) 12Methoxybenzaldehyde4-Methoxybenzonitrile1 HNMR(CDCl3)d=7.40(2H,d),6.95(2H,d),3.73(3H,s) 132-Naphthaldehyde2-Naphthonitrile1 HNMR(CDCl3)d=8.35–8.37(1H,m),7.89–8.01(3H,m)7.50–7.70(3H,m) 14Vanillin4-Hydroxy-3-methoxybenzonitrile1 HNMR(CDCl3)d=7.45(1H,s),7.27(1H,d),7.01(1H,d),5.32(1H,s),3.82(1H,s)
after purification. A maximum of seven cycles was done and the calculated yield was of 93% after the seventh cycle, showing very low degradation in the catalytic activity of ZP material (figure 11). The material was retained in similar manner as above after every cycle.
The reaction was carried out using various aromatic and heteroaromatic aldehydes. The conversion to nitrile occur- red in under 3 min, no matter the substitution on the aro- matic ring and the yields were exceptionally high (table4).
The synthesized nitrile compounds were confirmed using FT-IR, which shows a sharp peak at 2220–2245 cm–1 attributing to (–C:N). The GC MS results were recorded and m/z values are shown in table 4. The NMR spectral details of microwave-assisted catalytic conversion to nitriles are represented in table 5, while the comparative study on the organic transformation with the reported methods are shown in table 6.
4. Conclusion
ZP NPs have been synthesized by combustion method using low-cost novel fuel. XRD pattern confirms the formation of ZrPO4. SEM shows flake-like structure and energy disper- sive X-ray analysis show the presence of all the elements.
TEM images show honeycomb-like structure. FT-IR shows the presence of different vibrations. It shows good catalytic activity for the degradation of MB dye.
Synthesis of nitriles was fruitful using hydroxylamine hydrochloride and ZPs catalyst assisted by microwave radiation. The above-mentioned strategy has numerous advantages like very short reaction time, high selectivity and high purity. The reported procedure is also a green approach towards the synthesis, since there was no use of toxic substances that gives this methodology an edge over other reported procedures.
Acknowledgements
One of the authors Nagaraju acknowledges VGST, Govern- ment of Karnataka (SMYSR, GRD No. 498), for financial support to procure UV-Visible photoreactor and DST
Nanomission (SR/NM/NS-1262/2013), New Delhi, Govern- ment of India, for financial support.
References
[1] Thakur M, Sharma G, Ahamad T, Ghfar A A, Pathania D and Naushad M 2017 Colloids Surf. B: Biointerfaces 157 463
[2] Naik M M, Naik H B, Nagaraju G, Vinuth M, Vinu K and Rashmi S 2018J. Mater. Sci: Mater. Electron.2920414 [3] Pathania D, Katwal R, Sharma G, Naushad M, Khan M R
and Ala’a H, 2016Int. J. Biol. Macromol.87374
[4] Gundogdu A, Ozdes D, Duran C, Bulut V N, Soylak M and Senturk H B 2009Chem. Eng. J.15369
[5] Kaushik P and Malik A 2009Environ. Int.35141
[6] Zhao Q, Xing Y, Liu Z, Ouyang J and Du C 2018Nanoscale Res. Lett.1369
[7] El-Sheekh M M, Gharieb M and Abou-El-Souod G 2009Int.
Biodeterior. Biodegr.63704
[8] Huang H, Liu J, Zhang P, Zhang D and Gao F 2017Chem.
Eng. J.307706
[9] Saravanan R, Sacari E, Gracia F, Khan M M, Mosquera E and Gupta V K 2016J. Mol. Liq.2211033
[10] Wang H, Zhang L, Chen Z, Hu J and Li S 2014Chem. Soc.
Rev.435244
[11] Fujishima A and Honda K 1972Nature23838
[12] Tan I, Ahmad A and Hameed B 2008J. Hazard. Mater.154 346
[13] Tan I, Ahmad A and Hameed B 2008Desalination22528 [14] Kant S, Pathania D, Singh P, Dhiman P and Kumar A 2014
Appl. Catal. B: Environ.147352
[15] Roy A, Bulut O, Some S, Mandal A K and Yilmaz M D 2019 RSC Adv.92702
[16] Vinay S, Nagarju G, Chandrappa C and Chandrasekhar N 2019SN Appl. Sci.1477
[17] Sharygin L, Kalyagina M and Borovkov S 2005 Russ.
J. Appl. Chem.78228
[18] Hogarth W H, da Costa J C D, Drennan J and Lu G M 2005 J. Mater. Chem.15758
[19] Bermu´dez R A, Colo´n Y, Tejada G A and Colo´n J L 2005 Langmuir21895
[20] Santiago M E B, Declet-Flores C, Dı´az A, Ve´lez M M and Bosques M Z 2007Langmuir237817
[21] Shuai M, Mejia A F, Chang Y-W and Cheng Z 2013 CrystEngComm.151977
Table 6. Comparative study on the organic transformation with the reported methods.
Catalyst/reagent Conditions Time Yield (%) Reference
NH4OAc, I2and TBHP Under reflux 6 h 86 [60]
Copper fluorapatite (CuFAP)/TsCl Solvent-free, 100C 6 h 94 [61]
TiO2@CuO@Chromite/K4Fe(CN)6 Solvent-free at RT 25 min 96 [62]
Chloramine-T/KI THF/acq ammonia 1.5 h 90 [63]
NH4I DMSO/electrolysis 4 h 96 [64]
ZrPO4 Microwave 250 W 2–3 min 98 This study
[22] Dı´az A, David A, Pe´rez R, Gonza´lez M L and Ba´ez A 2010 Biomacromolecules112470
[23] Antonetti C, Melloni M, Licursi D, Fulignati S and Ribechini E 2017Appl. Catal. B: Environ.206377
[24] Kelly C B, Lambert K M, Mercadante M A, Ovian J M, Bailey W F and Leadbeater N E 2015 Angew. Chem. 127 4319
[25] Hyodo K, Togashi K, Oishi N, Hasegawa G and Uchida K 2017Org. Lett.193008
[26] Fleming F F, Yao L, Ravikumar P, Funk L and Shook B C 2010J. Med. Chem.537917
[27] Ghosh P, Saha B, Pariyar G C, Tamang A and Subba R 2016 Tetrahedron Lett.573618
[28] Ellis G P and Romney-Alexander T M 1987Chem. Rev.87 794
[29] Bini L, Mu¨ller C, Wilting J, von Chrzanowski L, Spek A L and Vogt D 2007J. Am. Chem. Soc.12912623
[30] Koelsch C F and Whitney A 1941J. Org. Chem.6803 [31] Nishiyama K, Oba M and Watanabe A 1987Tetrahedron43
700
[32] Veisi H 2010Synthesis20102635
[33] Sharghi H and Sarvari M H 2002Tetrahedron5810328 [34] Ghosh P and Subba R 2013Tetrahedron Lett.544887 [35] Reddy M M and Pasha M 2010Chin. Chem. Lett.211028 [36] Das V K, Harsh S and Karak N 2016Tetrahedron Lett.57
553
[37] Nandi G C and Laali K K 2013Tetrahedron Lett.542179 [38] Sridhar M, Reddy M K K, Sairam V V, Raveendra J and
Godala K R 2012Tetrahedron Lett.533424
[39] Anandakumar B S, Reddy M B M, Tharamani C N, Pasha M A and Chandrappa G T 2013Chin. J. Catal.34710 [40] Rokade B V and Prabhu K R 2012J. Org. Chem.775370 [41] Chen Q, Fang C, Shen Z and Li M 2016 Electrochem.
Commun.6455
[42] Gupta P and Paul S 2014Catal. Today236170
[43] Baig R N and Varma R S 2012Chem. Soc. Rev.411584 [44] Pa¨sha M and Nizam A 2010Synth. Commun.401279
[45] Liu X-Q, Wang D-Y, Wang X-L, Chen L and Wang Y-Z 2011Polym. Degrad. Stab.96777
[46] Horsley S E, Nowell D V and Stewart D T 1974Spectrosc.
30535
[47] Nagaraju G, Shubha J, Manjunath K and Dupont J 2018Int.
J Hydrogen Energy434035
[48] Liu L, Li J, Dong J, Sˇisˇak D, Baerlocher C and McCusker L B 2009Inorg. Chem.488954
[49] Barhon Z, Saffaj N, Albizane A, Azzi M, Mamouni R and El Haddad M 2013J. Mater. Environ. Sci.3884
[50] Chen R, Wang J, Wang H, Yao W and Zhong J 2011Solid State Sci.13635
[51] Das D, Baliarsingh N and Parida K 2007 J. Mol. Catal. A 261261
[52] Gupta V K, Pathania D, Singh P, Rathore B S and Chauhan P 2013Carbohydr. Polym.95440
[53] Pica M, Nocchetti M, Ridolfi B, Donnadio A and Costantino F 2015J. Mater. Chem. A35534
[54] Daneshvar N, Salari D and Khataee A 2003J. Photochem.
Photobiol. A: Chem.157116
[55] Gupta H and Tanaka S 1995Water Sci. Technol.3154 [56] Davis A P and Huang C 1991Water Res.251278 [57] Behnajady M, Modirshahla N and Hamzavi R 2006
J. Hazard. Mater.133232
[58] Xu H, Xu Y, Li H, Xia J and Xiong J 2012Dalton Trans.41 3394
[59] Wang X, Li J-G, Kamiyama H, Moriyoshi Y and Ishigaki T 2006J. Phys. Chem. B1106809
[60] Fang C, Li M, Hu X, Mo W and Hu B 2017RSC Adv.71489 [61] Chavan S S, Pathan M Y, Shaikh T M and Mulla S A 2017
Open J. Synth. Theory Appl.623
[62] Sajadi S M, Pirouei M, Salih N A, Kolo K and Hamad S M 2020Environ. Sci. Eur.3214
[63] Zhu Y-Z, Zhang X-Q, Liu F, Gu H-M and Zhu H-L 2013 Synth. Commun.432948
[64] Qu Q, Gao X, Gao J and Yuan G 2015Sci China Chem.58 750
