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Formation of New Products in a Solid-Solid Reaction in the Presence of Organic Solvent Impurity

Rabia Ahmad1*and Qamer Faisal1

1Department of Chemistry, Faculty of Natural Sciences, Jamia Millia Islamia (Central University) Jamia Nagar, New Delhi, 110 025 India

DOI:http://dx.doi.org/10.12944/CWE.6.1.16

We discuss the formation of new products in a solid – solid reaction in the capillary as in well as in bulk in the presence of an organic solvent impurity in a small amount. Three reactions namely KI + HgCl2, CuI + HgCl2and AgI + HgCl2were studied. It was found for some of the organic solvent impurities, a small amount of some substance appeared in the half occupied by HgCl2. Thus it became clear that some of the organic substances were reacting with HgCl2to produce a new substance which be an organo-metallic product. In this light HgCl2 was made to react with the different solvents. However, the new product could be separated out only in two cases, with Cyclohexanone and Dimethylsulfoxide. A black coloured product was formed with Cyclohexanone and with Dimethylsulfoxide the new product was of a light greenish colour. With the other solvents like Acetophenone and Nitrobenzene, the product, if formed, could not be separated out. So a preliminary study of the two products naming these as product A and product B formed with Cyclohexanone and Dimethylsulfoxide respectively has been done. The product A is formed by the reaction of Cyclohexanone solvent with HgCl2和产品B是由Dimethy的反应lsulfoxide solvent with HgCl2both at 80ºC, for 5 hours. The preliminary studies carried out were measurement of molecular weight (by elevation of boiling point method), ionicity, XRD, FTIR etc.


New Products; Organic Solvents; Molecular Weight; Ionicity; XRD; FTIR

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Ahmad R, Faisal Q. Formation of New Products in a Solid-Solid Reaction in the Presence of Organic Solvent Impurity. Curr World Environ 2011:6(1);115-124 DOI:http://dx.doi.org/10.12944/CWE.6.1.16

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Ahmad R, Faisal Q. Formation of New Products in a Solid-Solid Reaction in the Presence of Organic Solvent Impurity. Curr World Environ 2011:6(1);115-124. Available from://www.a-i-l-s-a.com/?p=1295


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Received: 2011-04-12
Accepted: 2011-06-17

Introduction

Many solid-solid capillary reactions have been studied during the last many years e.g.1-4In the studies normally carried out so for, both the solid reactants do not have any impurities. The main motivation of the earlier work, including that of the senior author (R.A.) in this field was to obtain a better understanding of the reaction mechanism of solid-solid reactions eg.2,5Introduction of simple organic impurities was a step in this direction. While studying the solid-solid capillary reactions in the presence of small amounts of some organic solvent impurity, that a small amount of some substance appeared in the half occupied by one of the reactants. Thus it became clear that some of the organic substances were reacting with one of the reactants to produce a new substance which be an organo – metallic product.

Here, we discuss the formation of new products due to the presence of an organic solvent impurity in a small amount. The reactions studied are KI+HgCl2, CuI + HgCl2and AgI + HgCl2in the presence of small amount of organic solvent impurity.

The two reactants when packed side by side in a capillary tube of a narrow diameter, say 0.5 cm after moistening with different solvent impurities and kept in an oven maintained at 80oC showed some new product on HgCl2side in two cases.

In the light of the indication from capillary studies HgCl2与不同的反应溶剂。如何ever, the product could be separated out only in two cases, with Cyclohexanone and Dimethylsulfoxide. A black coloured product was formed with cyclohexanone and with Dimethylsufloxide the new product was of a light greenish colour. With the other solvents like Acetophenone and Nitrobenzene, the product, if formed could not be separated out. So, we have made a preliminary study of the two new products, naming these as product A and product B respectively. The product A is formed by the reaction of Cyclohexanone solvent with HgCl2和产品B是由Dimethy的反应lsufloxide solvent with HgCl2, both at 80ºC, for 5 hours.

Experimental

Method of Preparation


We take 4 gms of well ground HgCl2(99.9% Merck) reactants, moistened with about 0.4 ml of Cyclohexanone solvent (99% Merck) on a watch glass. Then it is put in an oven at constant temperature of 80º C, for 5 hours. In this way,a black coloured product is formed,this is called product A Same procedure is adopted for the Dimethylsulfoxide solvent (99% Merck). HgCl2is moistened with 0.4 ml of the double distilled solvent and the same procedure is followed in this case also. A light greenish coloured product is formed, this is called product B. Powdered crystals of the new products are taken for observation, measurement and other studies with simple techniques for finding out their physical properties etc. These are given in Table 1.

Measurement of Molecular Weight (By Elevation of Boiling Point Method)

The equation relating the boiling point elevation with the molecular weight of the solute is given as

where M2is the molecular weight of the solute, W2is the mass of solute, Kbis the molal elevation constant, W1is the mass of the solvent and Tbis the boiling point elevation due to the presence of the solute. THF is used as solvent.

Table 1: Physical properties of new products Table 1: Physical Properties of New Products
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Table 2: Result of the measurements of the molecular weight of the products with Thf as solvent Table 2: Result of the Measurements of the Molecular Weight of the Products with Thf as Solvent
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Tbis measured by a digital electronic thermometer.

Benzoic acid and Acetanilide are taken as standard solute. A known small amount of the solute is added to known amount of THF solvent and the elevation of boiling point is found out. All chemicals used are 99% purity Merck chemicals.

The Kboccurring in the formula for the determination of molecular weight is found out using Benzoic acid and Acetanilide as solute. The mean value of Kbusing Actanilide as solute is used for the determination of molecular weight. The mean value of Kbfor THF is 191.45. These molecular weights are given in Table 2.

Measurement of Some Other Properties of this New Product Such as Ionicity, XRD, FTIR etc

The kinetics of the reaction is studied by placing 400 mgms of HgCl2崔和相同数量的近距离接触near the middle, first without any impurity, and then after mixing with the two new products formed, as impurities, taken turn by turn. Both the reactants are 99.9% purity Merck chemicals. The internal diameter of the pyrex glass tube is 0.5 cm and about 5 cm length. These are kept in an air thermostat oven, controlled upto 0.5º C to 1ºC at 80ºC. The product thickness is measured with a traveling microscope having a least count of 0.01mm at equal intervals of time (15 min). The results are given in Fig. 1 and the corresponding digital data are given in Table 3.

Table 4: XRD of Pure HgCl2 Table 4: XRD of Pure HgCl2
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The X-ray diffractogram of HgCl2and the two products are obtained. These are given in Figs. 2-4. The corresponding digital data are given in Tables 4-6. The digital data of some of the most prominent diffraction peaks is given in Table 7. The near – matching normal mode frequencies of HgCl2and the two products are given in Table 8 (a) and the remaining ones are given in Table 8 (b). The FTIR spectrum of HgCl2and the two products are given in Figs. 5-7.

Discussion

We see from Table 7 that the prominent peaks of product A are very nearly at the same place as that of HgCl2. This means that HgCl2molecule remains more or less as such in product A, with some organic group getting attached to the HgCl2molecule, consistent with the molecular weight of product A. This proposal is consistent with observations because the organic group is expected to diffract X-rays very-very scantily.

Table 5: XRD of product A Table 5:XRD of product A
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On the other hand, for product B, the 100% intensity is diffracted for d=8.0289 which is a totally new d-value. Also there is a new peak of 34.8% intensity at d=3.4618. There is also a new peak of intensity 15% at d=2.7696. Rest of the prominent d values for product B are more or less same as for HgCl2From this, we may conclude that at least one chlorine is replaced by an organic group consistent with the observed molecular weight. This should account for the observed X-ray data.

Table 6: XRD of product B Table 6:XRD of product B
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From Table 8 (a), we also notice many near matching between the normal mode frequencies of HgCl2and those of product A. There are fewer near matching between the frequencies of HgCl2and those of product B. This is consistent with our proposal regarding the new products.

We may tentatively suggest the following structures for the new products. Then one should have a very close look at the FTIR and other supporting data to eliminate many of the proposed structures to hopefully arrive at the best choice.

Table 7 Table 7
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Table 8(a , b) Table 8 (a) and (b)
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图2:X -射线衍射gram of HgCl2 Figure 2: X- Ray diffractogram of HgCl2
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Fig. 3: X- Ray diffractogram of Product A Figure 3: X- Ray diffractogram of Product A
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Fig. 4: X- Ray diffractogram of Product B Figure 4: X- Ray diffractogram of Product B
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Fig. 5: FTIR of HgCl2 Figure 5: FTIR of HgCl2
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Fig. 6: FTIR of product A Figure 6: FTIR of product A
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Fig. 7: FTIR of product B Figure 7: FTIR of product B
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Proposed structure of the new product being given heremerely as one of the examples Formula weight Observed Molecular
Product A (HgCl2 )CH3 SHO 287.54 287.07
Product B Hg SHO 299.54 303.25


The above are merely examples and these are not even good examples. Out of the many proposals, that one may make, one should be able to arrive at the correct structure, mainly on the basis of the FTIR and other supporting data. That is not being done here.

The normal mode frequencies of the two solvents, Cyclohexanone and Dimethylsulfoxide can be seen from Fig. 8 and 9, where the frequencies are noted in digital form over the spectrum.

Concluding Remark

One structure for product A and one for product B are tentatively proposed. More such structures have to be proposed and assessed against the observed molecular weighty and the spectra etc. Only then one may arrive at a unique structure for each of the two products.

Fig. 8: FTIR of Cyclohexanone Figure 8: FTIR of Cyclohexanone
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Fig. 9: FTIR of Dimethylsulfoxide Figure 9: FTIR of Dimethy lsulfoxide
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Acknowledgements

We wish to express our thanks to Prof. M.A. Wahab, HOD Department of Physics, JMI, New Delhi for X-ray measurement. Thanks are also due to Prof. Kamaluddin, Department of Chemistry, IIT Roorkee for X-ray and FTIR measurements. We would also like to thank Prof. Amir Azam for FTIR measurements. Special thanks are due to the Ex-Head of the Chemistry Department Prof. Kishwar Saleem, for extending to us the facilities of the Department. We are also thankful to Prof. Sharif Ahmad, Head Department of Chemistry, JMI, New Delhi.

Referenecs

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  5. Rahman R., Ph.D. Thesis, Aligarh Muslim University, Aligarh (1984).
  6. Maron S.H. and Prutton C.F., Principles of Physical Chemistry, 4th ed, Amerind Publishing Co. New Delhi, Bombay, Calcutta, New York (1965).