Synthesis and Characterization of Bi13B0.48V0.49-xPxO21.45 and Efficient Catalyst for the Synthesis of 2,3-dihydroquinazolin-4(1H)-ones Derivatives Synthesis

A new compound has been found in the system Bi13B0.48V0.49-x PxO21.45 (with 0≤x≤0.34), were prepared by the direct solid-state reaction of Bi2O3, (NH4)2HPO4, V2O5, and B2O3. This material melts congruently and it crystallize with the sillenite structure (space group I23) and form a solid solution with the cubic lattice parameter increasing from with a = 10.1568 Å to 10.1436 Å with increasing of P2O5 molar. Consequently, the new composites belong to -variety of solid state. The samples have been characterized by Fourier transform infrared spectroscopy (FT-IR), diffraction XRD and scanning electron microscopy (SEM) coupled to the EDX. On the other hand, the valorization of the prepared composites was performed by using them as heterogeneous catalyst in the 2,3-dihydroquinazolin-4(1H)-ones derivatives synthesis. The catalyst is stable (as a bench top catalyst) and reusable. Copyright © 2020 BCREC Group. All rights reserved


Introduction
Metal oxides have been recognized as catalysts for various applications. Some notable examples of these solids used in heterogeneous environmental photocatalysis include TiO2, ZnO, Bi2O3, CdS, WO3, SnO2, ZnS, CdTe, CdTe, Fe2O3, AgNbO3, and SrTiO3 [1]. Bi2O3 is an important inorganic functional material. It has been the subject of particular attention due to

Materials and Instrumentation
The characterization of the prepared phases is carried out by X-ray diffraction on powder using a SIEMENS 5000 diffractometer from the PANALYTICAL company with copper anticathode (k Cu=1.5406 Å), the different diagrams obtained are recorded at room temperature, in a wide angular range (20° ≤ 2Ɵ ≤ 60°) with a step of 0.06° and for a counting time of 40 s. XRD data processing is performed by X'Pert Highscore Plus. The intermediate and final compounds resulting from the thermal decomposition of the precursors were analysed using Fourier Transform Infrared Spectrophotometer (FTIR) ALPHA.
The morphology and size of the synthesized powders were examined by scanning electron microscopy SUPRA 40 VP GEMINI ZEISS COLUMN, coupled with an EDX type analyzer (Energy Dispersive X-Rays Spectroscopy, Oxford instruments X-Max 20 mm 2 ) to determine the local quantitative elemental composition of a sample, with a maximum resolution of 1 µm at voltages ranging from 10 to 25 kV.
All chemicals used in this study were purchased from Aldrich and Fluka and are used without further purification. The synthesized products were characterized by their physical properties and by comparison with authentic samples that exist in the literature. The 1 H NMR spectra were recorded on an advanced 300 MHz Bruker instrument and the 13 34 were prepared by standard solid-state meth-ods. Appropriate amounts of Bi2O3, B2O3, ((NH4)2HPO4) and V2O5, were grounded together in an agate mortar. The dried powders were heated at 350 °C for 15 hours. After this first heating, the mixtures are removed from the oven, and finely ground and then heated a second time at a temperature of 700 °C for 15 hours. The simples were ground into powder for characterization.
2.3 General Procedure for the 2,3dihydroquinazolin-4(1H)-ones Derivatives Synthesis A mixture of (1 mmol) anthranilamide and (1 mmol) aromatic aldehyde in (3 mL) ethanol were reacted in the presence of Bi13B0.48V0.49-x PxO21.45 with (0≤x≤0.34) (Scheme 1). The mixture was stirred under reflux for 10 to 40 min. The reaction is followed by (TLC) (Chloroform/Methanol, 8/2). After completion of the reaction, the mixture was cooled at room temperature. Then, dichloromethane (5 mL) was added to the mixture to separate the catalyst by simple filtration; the filtrate was evaporated until the precipitates were formed. The product was purified by recrystallization with ethanol to obtain the 2,3-dihydroquinazolin-4(1H)-ones. The catalyst may be reactivated later by washing with ethanol to remove the products that may be present on its surface and then dried before being reused. The products obtained 3a-3g are identified by the spectroscopic methods NMR H 1 , NMR C 13 as follow: 2-Phenyl-2,3-dihydroquinazolin-4(1H)-one 3a: 1 13

Characterization of Catalysts
The X-ray crystallographic analysis was performed for the phases obtained within the quaternary system Bi2O3-B2O3-P2O5-V2O5, the substitution of vanadium by phosphorus revealed the existence of a total solid solution of the selenite type of formula Bi13B0.48V0.49-x PxO21.45 with (0≤x≤0.34). The four samples were analyzed by X-ray diffraction and the results obtained are presented in Figure 1.
These samples are identified by comparing the experimental diagrams with the reference data of the JCPDS standard data (Joint Committee for Powder Diffraction Standards). All the observed diffraction peaks can be indexed to the standard data of Bi13B0.48V0.49-x PxO21.45 with card No 00-044-0425. The progressive substitution of vanadium by phosphorus shows the existence of a pure phase which crystallizes in a cubic system of space group I23 with a = 10.1568 Å for x = 0, a = 10.1536 Å for x = 0.14, a = 10.1518 Å for x = 0.24 and a = 10.1436 Å for x = 0.34. This phase will be designated throughout this work by -Bi2O3.
The various compositions of the solid solution are perfectly indexed in the cubic system. Table 1 shows the indexing of the diffraction peaks and the observed and calculated reticular distances. The cell parameter was refined by TREOR 90, a sub-program of the Full prof software. After searching for peaks in each is saved in a TREOR format to generate a data file. The refinement results are displayed in output files. The variations in the "a" cell parameter are shown in Figure 2.
From Figure 2, it can be seen that the linear decrease in the mesh parameter is due to the difference in the size of the ionic rays of the phosphorus and vanadium cations of the same coordination (V). In effect, by replacing the P 5+ ions of ionic ray with V 5+ ions, a small cation is replaced by a large cation, which favours the observed decrease. This shows that the substitution of phosphorus by vanadium leads to the formation of a solid solution (sillenite type).
Another information that we can extract from X-ray diffraction diagrams is the average crystalline crystal size. Indeed, Scherrer [13,14] has shown that the size of the particles is inversely proportional to the width of the diffraction peaks. This crystal size can be obtained by applying the following relation (Equation 1).
(1)  It can be seen that the average size of the crystallites D of the cubic phase decreases as a function of x. This leads to the conclusion that the average size of the crystallites depends on the composition of the solid solution and that the substitution of phosphorus by vanadium leads to the formation of smaller crystallites, which is a priori of interest for catalysis. The reduction in grain size leads to an increase in the specific area, which results in an increase in catalytic activity [15].
The infrared spectra of Bi13B0.48V0.49-xPxO21.45 with (0≤x≤0.34) are recorded at room temperature in the frequency range between 100 and 400 cm -1 as shown in Figure 3. The observed bands along with their vibrational assignments of samples have been tabulated in Table 3.
The IR spectra show a band around 1387 cm -1 which is attributed to the asymmetric stretching mode B-O in the orthoborate units (BO3) [31]. It can be attributed to the vibrations of the B-O-bonds as well as to the vibrations of B-O bonds present in borate rings [32]. The band at 1072 cm -1 , corresponding to (νasPO3) moves towards the high frequencies at 1094 cm -1 this is due to the changes in angular connection inside the chains P-O-P [29,30]. Indeed a new band emerges in the infrared spectra at 960 cm -1 . This band is due to the simultaneous vibration isolated V=O groups in a vanadyl bipyramid triangular base VO5 and the symmetric vibration PO3 (νsPO3) [26][27][28]. The band around about 845 cm -1 correspond more particularly to vibration elongations of the Bi-O bonds in the pyramid units [BiO3] [25]. However the band near 760 cm -1 has been assigned to asymmetric stretching modes (νas POP) [20][21][22][23][24]. The band around 660 cm -1 contributing to the vibrations of BO4 units and would correspond more particularly to the vibrations of BO4 units present in rings such as diborate units, or tri, tetra or pentaborate units [19]. The band at 570 cm -1 is attributed to the vibrations of the V-O-V links in VO4 tetrahedra [18]. Finally, the band centred at 521 cm -1 may be attributed to the Bi-O-Bi stretching vibrations of BiO6 Octahedral units [17] and another band situated at 430 cm -1 is assigned to the Bi-O vibration mode in the [BiO6] configuration [16].
Scanning electron microscopy provides information not only on the morphology, distribution and size of grains or agglomerates but also on the local chemical composition when coupled with an X-EDX analyzer shown in Figure  4.

Bulletin of Chemical Reaction Engineering & Catalysis, 15 (3), 2020, 866
Copyright © 2020, BCREC, ISSN 1978-2993  The resulting images are shown in Figure 4, respectively. These images show a micrograph of particles that are globally heterogeneous and crystallized as randomly distributed clusters. The grains appear with different shapes and texture relative to the presence of some small holes, inside the compounds which are due to low porosity.
To identify the elements contained in the synthesized powders and to determine their compositions an EDX chemical analysis was carried out on some prepared compositions ( Figure 5). The spectra clearly show the presence of the chemical elements that make up the synthesized compounds without any element foreign to the materials.
3.2 Catalytic Test of Bi13B0.48V0.49-x PxO21.45 The condensation between benzaldehyde and anthranilamide is chosen as a model reaction to test the catalytic activity of Bi13B0.48V0.49-xPxO21.45 with (0≤x≤0.34). Firstly, the model reaction was carried out in the absence and presence of the catalyst. The results obtained are shown in the Table 4.
The results presented in Table 5 show that in the absence of catalyst, only traces of the product 3a obtained even after 60 min. While  34), the product 3a is obtained in short reaction times (10-25 min) with good yields (78-87%). These results clearly shows the interesting catalytic activity of the f ou r ca tal y sts used i n the 2 , 3dihydroquinazolin-4 (1H) -ones synthesis.
In addition, the comparison of the results obtained with x = 0 and that obtained with x = 0.14, x = 0.24 and x = 0.34, shows that a significant correlation exists between the catalysts and the catalytic activity, That is to say, when we go from x = 0 to 0.34, the catalytic ac-tivity decreases, which is explained by the decrease in the specific surface.
In order to optimize the reaction solvent, we examined the influence of the solvent on the yield of product 3a, by varying the nature of the reaction solvent, such as protic polar (Ethanol , Methanol), p olar ap rotic (Acetonitrile) and apolar aprotic (Chloroform, Dioxane). The yields obtained are summarize in Table 5. The results given in Table 5 show that the reaction is clearly favored in protic polar solvents and more specifically in ethanol, this is available for the model reaction where the Bi13B0.48V0.49-x PxO21.45 with (0≤x≤0.34) catalysts were applied, the product 3a is obtained with yields which are 87, 83, 80, and 78% respectively. However, in the case of methanol it is noted that it allows obtaining the product with a lower yield than ethanol even though its dielectric constant is greater compared to the ethanol one, which may be explained by the fact that the methanol is more acidic than the ethanol, thus the O-H bond is more polar in methanol than in ethanol. Therefore, the methanol tends to liberate the proton more easily, unlike to the ethanol which just allows the polarization of the reagents leading to the formation of the desired product 3a with a good yield. Moreover, the appropriate solvent for each organic synthesis depends on the nature  3  18  87  5  18  88  7  18  90  9  18  87  10  18  83   x= 0.24   3  20  86  5  20  88  7  20  85  9  20  82  10  20  80   x= 0.34   3  25  79  5  25  81  7  25  83  9  25  79  10 25 78 Table 6. Influence of the catalyst amount on the 2,3-dihydroquinazolin-4(1H)-one synthesis a a Reaction conditions: benzaldehyde (1 mmol), anthranilamide (1 mmol), EtOH, catalyst amount (x mg). b Isolated yields of the reaction mixture. Therefore, the use of ethanol as a solvent facilitates the formation and the separation of the charges on the active sites of the reagents, indeed this process is caused by the electrostatic interaction involved between the atomic charge on the atom forming polar bond of the solvent with the active atomic center which possesses the opposite sign of charge, in the reagent, this interaction makes easy the formation of the final product 3a.
As regards the aprotic polar solvents and apolar (Acetonitrile, Dioxane, Chloroform), used in this part of our study, one can notice that the yield obtained in presence of each solvent is lower than that obtained in ethanol. One can deduce that ethanol is the appropriate solvent allowing to obtain the desired product with excellent yields.
The next study of this work has been focused on the determination of the appropriate  catalyst amount for the synthesis of product 3a.
The model reaction has been realized in various catalyst amount from 3 to 10 mg. The results obtained are collated in Table 6. From the results obtained (Table 6), we can clearly see the influence of the amount of catalyst on the yield. The best yield 92, 90, 83 and 88% has been obtained in presence optimum masses of the catalysts are 7 mg of x= 0, 0.14, 0.34 and 5 mg of x= 0.24 respectively.
The long-term durability of the catalyst must be also studied to prove its catalytic efficiency. For that, the model reaction was performed under the optimal conditions of solvent and catalyst amount. After reaction completion, the catalyst was recovered and washed Scheme 3. A plausible mechanism for the formation of 2,3-dihydroquinazolin-4(3H)-ones.

Catalysts
Reaction  with EtOH, stirred for 10 min, then dried at 100 °C to be ready the next reuse. The obtained yields are presented in Figure 6. The results shown that the catalytic activity was not affected even after five cycles of reuse since the yield of product 3a remains almost unchanged. For the generalization study of 2,3dihydroquinazolin-4(1H)-one derivatives synthesis, the reaction was carried out under optimal conditions using various aromatic aldehydes with different functional groups to react with anthranilamide (Scheme 2). The obtained results are collected in Table 7. The results show that whatever the substituent (R) of the used aromatic aldehyde, the final product is obtained with an excellent (80-95%) yield in short reaction time (10-40 min). Indeed, the nature (donor/attractor) of the aldehyde substitution group has not a significant effect on the catalyst efficiency.
One of the key points to understand the reaction mechanism in heterogeneous catalysis is the determination of the active surface sites and the activation processes. The presence of a large population of electron pairs on the surface compounds, such as: B 3+ , Bi 3+ , V 5+ , P 5+ , and O 2indicates that the surface of Bi13B0.48V0.49-x PxO21.45 presents certainly multicatalytic active sites such as basic sites (BS) and acidic sites (AS).
The synthesis mechanism of 2,3dihydroquinazolin-4(3H)-ones formation was mostly based on direct cyclocondensation process; the plausible mechanism for this reaction was proposed in Scheme 3. Initially, the acidic sites coordinate with the oxygen atom of the aldehyde and facilitate the nucleophilic attack the amino group of anthranilamide to form intermediate 2. Then, the product 2 is activated by catalyst to facilitate the intermolecular nucleophilic attack of nitrogen on the imine carbon to directly give the desired 2,3dihydroquinazolin-4(3H)-ones (3a-g).
In order to estimate the efficiency of the used catalysts in the 2,3-dihydroquinazolin-4(1H)-one synthesis, a comparative study has been carried out between Bi13B0.48V0.49-x PxO21.45 and other catalyst reported in the literature ( Table 8). The results (Table 8) shows that the four catalysts possess interesting catalytic activity compared to other catalysts reported in the literature in terms of the obtained reaction time and yield concerning the 2,3dihydroquinazolin-4(1H)-one synthesis.

Conclusions
The elaboration of Bi13B0.48V0.49-x PxO21.45 with (0≤x≤0.34), gives a solid solution it behaves as good solid catalysts with a percentage reaching 92%. Catalytic activity decreases with increasing phosphorus. It can be seen that the average size of the crystallites D of the cubic phase (rich in bismuth) decreases as a function of x. This makes it possible to conclude that the average size of the crystallites depends on the composition of the solid solution and that the substitution of vanadium by phosphorus leads to the formation of smaller crystallites, which is a priori advantageous for catalysis. The ability to recycle and reuse these catalysts remains an important advantage which will allow the opening of a field to very broad applications.