CLIAMS:1. A magnesium alkoxide framework having a surface area in the range of 200 m2/g to 270 m2/g and a pore volume in the range of 0.2 cm3/g to 0.35 cm3/g.
2. The magnesium alkoxide framework as claimed in claim 1, wherein said framework is obtained by reacting magnesium metal and a mixture of alcohol containing methanol and ethanol, using iodine as an initiator,
wherein, the ratio of magnesium metal to methanol is 1:6;
the ratio of magnesium metal to ethanol is 1:6; and
the ratio magnesium metal to iodine is 1:0.006.
3. The magnesium alkoxide framework as claimed in claim 1 comprises 26 wt% to 27 wt% of magnesium, 18 wt% to 22 wt% of ethoxy and 45 wt% to 55 wt% of methoxy.
4. The magnesium alkoxide framework as claimed in claim 1, wherein the particle size of the magnesium alkoxide framework is in the range of 11 micrometers to 16 micrometers.
5. A process for preparing a magnesium alkoxide framework, said process comprising reacting magnesium metal and a mixture of alcohol containing methanol and ethanol, using iodine as an initiator, said reaction being carried out initially at a temperature of 15 oC, and then the temperature of the reaction is raises up to to 60 oC, under stirring,
wherein, the ratio of magnesium metal to methanol is 1:6;
the ratio of magnesium metal to ethanol is 1:6; and
the ratio magnesium metal to iodine is 1:0.006:
6. The process as claimed in claim 5, wherein the reaction is initially maintained at a temperature of 15 oC for a time period ranging from 3 hours to 4 hours, the reaction is then maintained in the temperature range of 15 oC to 35 oC for 2 hours to 3 hours and finally the reaction is maintained in the temperature range of 35 oC to 60 oC for 3 hours to 4 hours.
7. The process as claimed in claim 5, wherein the stirring is carried out at a rotation speed in the range of 350 rpm to 400 rpm,
8. A Ziegler-Natta pro-catalyst prepared by using the magnesium alkoxide framework as claimed in claim 1, and using the Ziegler-Natta pro-catalyst for preparing polymers. ,TagSPECI:FIELD
The present disclosure relates to metal organic frameworks.
BACKGROUND
Metal organic frameworks (MOFs) have certain characteristics which make them a unique material. An MOF is formed by the arrangement of metal and organic moieties in a defined manner. It has large internal surface areas; ultralow densities; uniform channels, cavities and voids; and permanent porosity. Because of these exceptional properties, MOFs are being investigated for many potential applications, including gas storage, gas and chemical separations, chemical catalysis, ion exchange and drug delivery.
Various attempts have been made to provide MOFs of magnesium metal and alcohol. US8633124 suggests a process for the synthesis of spheroidal magnesium alkoxide having a surface area in the range of 1 m2/g to 20 m2/g. The process comprises reacting magnesium metal, in the presence of iodine, with a mixture of at least two alcohols by heating a mixture of magnesium metal, iodine and two alcohols. However, these MOFs do not have a large surface area and pore volume and therefore, the full potential of the MOFs cannot be achieved in terms of gas storage and reaction kinetics in which they are employed.
Therefore, there is still need of an MOF having a relatively large surface area and pore volume.

OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the conventional metal organic frameworks or to at least provide a useful alternative.
An object of the present disclosure is to provide a metal organic framework (MOF).
Another object of the present disclosure is to provide an MOF of magnesium and alcohol.
Yet another object of the present disclosure is to provide an MOF which possesses a relatively large surface area.
Still another object of the present disclosure is to provide an MOF which possesses a large pore volume.
Further object of the present disclosure is to provide a process for preparing an MOF.
Still further object of the present disclosure is to provide a process for preparing a Ziegler-Natta pro-catalyst using an MOF.
Other objects and advantages of the present disclosure will be more apparent from the following description and drawings which are not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a magnesium alkoxide framework having a surface area in the range of 200 m2/g to 270 m2/g and a pore volume in the range of 0.2 cm3/g to 0.35 cm3/g. The relatively large surface area of the magnesium alkoxide and the pore volume is due to the presence of a controlled amount of methanol in the framework. The ratios of the components in the magnesium alkoxide framework to achieve a surface area greater than 200 m2/g are as follows:
- magnesium metal to methanol is 1:6 and
- the ratio of methanol to ethanol is 1:1.
The present disclosure also relates to a process for preparing a magnesium alkoxide framework.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 is a graphical representation of the effect of varying methanol concentration on the time-temperature profile;
Figure 2 illustrates the extent of vigorousness of the reaction with increase in mole% of methanol;
Figure 3 is a graphical representation of the effect of varying iodine concentration on the time-temperature profile;
Figure 4 is a graphical representation of the effect of varying methanol concentration on the particle size distribution of an MOF;
Figure 5 is a graphical representation of the effect of varying iodine concentration on the particle size distribution of an MOF;
Figure 6 is a graphical representation of the effect of methoxy content inserted on surface area of an MOF;
Figure 7 illustrates the adsorption-desorption isotherms of an MOF at various concentration of methanol;
Figure 8 illustrates the SEM micrographs of magnesium alkoxide framework prepared using different concentrations of methanol; and
Figure 9 is a graphical representation of the solubility of synthesized material under various conditions.
DETAILED DESCRIPTION
The present disclosure provides a magnesium alkoxide (a type of MOF) framework containing a controlled amount of methoxy and ethoxy content, and having specified surface characteristics. It is believed that the surface characteristics of the magnesium alkoxide framework are dependent mainly on the amount of methoxy content. The magnesium alkoxide is obtained by reacting magnesium metal and a mixture of alcohols in the presence of a reaction initiator (iodine) with constant agitation.
To achieve the object of providing an MOF having relatively large surface area and pore volume, the amount of the reactants - magnesium metal, ethanol, methanol and iodine, are maintained in a particular ratio. In one embodiment, the ratio of
- the magnesium metal to methanol is 1:6;
- the magnesium metal to ethanol is 1:6; and
- the magnesium metal to iodine is 1:0.006.
In an embodiment of the present disclosure, the ratio of methanol to ethanol is 1:1.
The present disclosure also provides a process for the preparation of a magnesium alkoxide framework.
The inventors executed experiments by varying the concentrations of methanol in the mixture of ethanol and methanol both in the presence and in the absence of an initiator such as iodine. The magnesium alkoxide frameworks, thus obtained, were analyzed to determine the surface area characteristics. It is observed that when a particular concentration of methanol in the mixture of reactants is maintained, the surface area of the resulting magnesium alkoxide framework is surprisingly found to be very large for this type of materials which otherwise is not achieved. It is believed that the methanol molecule having higher kinetic energy has more number of collisions with magnesium metal compared to the ethanol molecule and hence, there is a higher probability of forming Mg-OCH3 as compared to that of Mg-OCH2CH3. The higher number of collisions of the methanol molecules with the magnesium metal is responsible for higher rate of reaction at the same temperature as compared to the bigger molecules of ethanol. The higher dipole moment of methanol is also responsible for a more electrostatic attraction towards the electropositive magnesium metal and hence, a strong chemical bond is formed between the magnesium and the methoxy moiety. This is also responsible for the higher rate of reaction between the magnesium metal and methanol as compared to ethanol, as more heat of lattice formation is liberated when methanol is reacted with magnesium and forms the solid Mg-OCH3. The Mg-OCH3 is more polar in nature as the electron cloud of the bond is more towards the electronegative – OCH3 group and hence, the bond formed between magnesium and – OCH3 is more ionic in nature. The more ionic character of the bond of Mg-OCH3 has a tendency to form a stronger lattice in its solid state structure due to more residual forces which are responsible for a solid with higher mechanical strength.
The process in accordance with the present disclosure involves mixing and reacting the reactants namely - magnesium metal, ethanol, methanol and iodine in a pre-determined amount. The reaction is carried out at a temperature which is incrementally increased in a step wise manner to obtain the magnesium alkoxide framework as a free flowing powder, after evaporating the alcohol. Initially, the reaction is maintained at a temperature of 15 °C for 3 hours to 4 hours. Next, the reaction is maintained in the temperature range of 15 °C to 35 °C for 2 hours to 3 hours and finally, the reaction is maintained in the temperature range of 35 °C to 60 °C for 3 hours to 4 hours. The step wise increase in the reaction temperature helps to control the rate of reaction (qualitatively observing the effervescences of hydrogen evolution as the reaction proceeds further), as temperature is one of the controlling parameter to get the desired kinetics. The reaction mixture is continuously stirred at a speed of rotation in the range of 350 rpm to 400 rpm. The excess amount of the mixture of alcohols is evaporated at 80 °C for 2 hours to 4 hours.
The free flowing powder obtained is collected and characterized for surface properties. From the characterization it is observed that the magnesium alkoxide framework possesses surface area greater than 200 m2/g, when the methanol: ethanol ratio is 50: 50, which is surprising for this type of organo magnesium compounds. In view of this, it can be stated that achieving a surface area greater than 200 m2/g for these types of compounds is inventive. Also, the pore volume of the magnesium alkoxide framework is in the range of 0.2 cm3/g to 0.35 cm3/g, and the mean particle size of the magnesium alkoxide framework is in the range of 11 micrometers to 16 micrometers, and the magnesium alkoxide framework comprises 26 wt% to 27 wt% of magnesium, 18 wt% to 22 wt% of ethoxy and 45 wt% to 55 wt% of methoxy in the final product, when the methanol: ethanol ratio is 50: 50.
The magnesium alkoxide framework prepared by the process of the present disclosure is characterized by various methods.
Chemical Composition: The free flowing solid powder of synthesized material under different conditions was analyzed for its chemical composition using titrimetric and gas chromatographic technique.
Particle Size Analysis: The particle size was measured by laser light scattering technique using Cilas-1190 instrument in liquid mode. The particles of the synthesized material were dispersed in a mineral oil during the measurement.
Surface Area Analysis: The surface area characteristics were measured by nitrogen adsorption on the surfaces of the materials using Brunauer–Emmett–Teller (BET) surface area analyzer (Sorpomatic-1990). The pore size and their distributions were measured through the desorption of nitrogen from the material using Barrett-Joyner-Halenda (BJH) algorithm.
Morphology: The morphology was examined by Field Emission Inc. (FEI) Inspect scanning electron microscope. Before the measurements, the sample was fixed on the carbon tape under nitrogen atmosphere and quickly loaded in the chamber. The voltage and working distance were varied during the measurements and the images were recorded.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. These laboratory scale experiments can be scaled up to industrial/commercial scale.
Experiments
A general process for the preparation of Magnesium alkoxide framework
A 4 neck 100 ml jacketed glass reactor was used after drying under nitrogen and then fitted with a mechanical stirrer having a speed of rotation of 400 rpm. A pre-determined amount of magnesium metals’ turnings (received from M/S Minmet) were added in the reactor. Similarly, a pre-determined amount of methanol and ethanol was added in the reactor. The reaction temperature was maintained at 15 °C by circulating oil in the reactor jacket by a Julabo oil circulator. A predetermined amount of sublimated iodine was then added in the reaction mixture. A predetermined time-temperature was followed during the reaction and after the completion of the reaction, the excess amount of the mixture of alcohols was evaporated by passing a nitrogen gas stream at an elevated temperature (80 °C) till the magnesium alkoxide framework in the form of powder became free flowing.
Experiment 1:
A series of experiments were carried out by varying the concentration of methanol during the preparation of the magnesium alkoxide framework as per the above described general process.
The exact mole% of the reactants used and the reaction conditions are shown in Table-1 below.
Table-1: The reaction conditions for synthesis of magnesium alkoxide
Mg-Metal Methanol Ethanol Initiator (I2 Mg : Methanol : Ethanol
Experiment No. Amount Amount Amount Amount) Methanol : Ethanol Charging
g ml ml g Mole Ratio Ratio in mole% Temp (°C)
(Ratio in mole%)
(mole) (mole) (mole) (mole )

MME-0 5.5 g 0 ml 135 ml 0.15 g 1:0:12 00:100 40
(0.2 mole) (0 moles) (2.4 mole) (0.0006) (8:0:92)

MME-10 5.5 g 10 ml 122 ml 0.15 g 1:1.2:10.8 10:90 40
(0.2 mole) (0.24 mole) (2.16 mole) (0.0006) (8:9:83)

MME-50 5.5 g 50 ml 72 ml 0.15 g 1:06:06 50:50 15
(0.2 mole) (1.2 mole) (1.2 mole) (0.0006) (8:46:46)

MME-75 5.5 g 73 ml 35 ml 0.15 g 1:09:03 75:25 15
(0.2 mole) (1.8 mole) (0.6 mole) (0.0006) (8:69:23)

MME-100 5.5 g 100 ml 0 ml 0.15 g 1:12:00 100:00 15
(0.2 mole) (2.4 mole) (0.0 mole) (0.0006) (8:92:0)

In these examples, the mole% for methanol and ethanol were varied, keeping the amount magnesium and iodine constant. It is seen from Table-1 that as the methanol amount is increased, the charging temperature for the reaction is comparatively lowered (15 oC). However, when the ethanol amount is increased, the charging temperature of the reaction was found to be higher (40 oC). More energy is required when the ethanol amount is increased in the process of the present disclosure.
Characterization of magnesium alkoxide framework obtained in Experiments MME-0, MME-10, MME-50, MME-75 and MME-100:
Figure-1 of the accompanying drawings presents the effect of methanol concentration on the rate of reaction. It is seen from Figure-1, that at lower concentration of methanol (10 mole%), the reaction temperature has to be ramped up frequently (the temperature ramping frequency is five) till 450 minutes and after that evolution of hydrogen was not observed visually. Thus, the reaction requires higher amount of heat and hence, the reaction is energy intensive. However, when higher amount of methanol (75 mole%) was used, the temperature is ramped up only thrice for getting the same extent of evolution of hydrogen (till 450 minutes of the reaction time). At higher concentrations of methanol, the reaction continues for a prolonged time without a need for frequent ramping of the temperature, which means that additional energy in the form of heat is not needed to proceed the reaction in the forward direction, indicating an energy efficient process. Thus, there is an inverse correlation between the rate of the reaction and the temperature ramping frequency. The higher number of temperature ramping frequency of the reaction indicates a low rate of reaction, while a lower ramping frequency of the reaction indicates a higher rate of reaction. The higher rate of reaction was qualitatively observed (visually) as the effervescences of hydrogen generated during the reaction between the magnesium metals and mixture of alcohols (ethanol and methanol) as a qualitative tool for the measurement of the rate of reaction. Here, the extent of hydrogen evolved is considered as the rate of reaction i.e., higher the amount of effervescences of hydrogen observed, the higher is the rate of reaction.
Further, the photographs of the reaction mixture were captured during the experiments, as presented in Figure-2 of the accompanying drawings. The extent of vigorousness of the reaction can be made out from the effervescences of hydrogen evolved during the reaction which is seen from the photographs (Figure-2). It is observed that the amount of effervescences increases when the mole% of methanol was increased from 10 mole% (Figure-2A) to 75 mole% (Figure-2C), thus the extent of reaction vigorousness was found to be in an increasing order.
The magnesium alkoxide frameworks obtained in these experiments were further characterized and the results are tabulated in Table-2.
Table-2: Physico-chemical characteristics of the magnesium alkoxide synthesized with different amount of methanol and ethanol
Experiment No. Methanol : Ethanol
Ratio in mole% Chemical Composition Particle Size Analysis (µm)
Surface Area Analysis
Mg (Wt %) Methoxy
(wt%) Ethoxy
(wt%) Yield
(g) D10 D50 D90 Mean Span
(D90-D10)/D50 Surface
Area
m2/g Pore
Volume
cm3/g
MME-0 00:100 22 0 77 25 15 31 49 32 1.1 10 0.07
MME-10 10:90 22 9 68 25 16 26 37 26 0.8 30 0.11
MME-50 50:50 27 52 20 21 5 15 27 16 1.5 265 0.33
MME-75 75:25 28 59 12 20 12 40 77 43 1.6 50 0.09
MME-100 100:00 27 72 0 21 Agglomerations 20 0.06
D10, D50 and D90 – Particle size (diameter) of 10%, 50% and 90% particles.
From Table-2, it is seen that as the amount of methanol increases from 0 mole% to 100 mole%, the amount of methoxy moiety also increases in the magnesium alkoxide framework, which is attributed to the smaller size (3.6 °A) of the methanol molecule with a higher dipole moment (1.69 D) as compared to the ethanol molecule (size 4.4 °A and dipole moment 1.68 D). The smaller size of methanol can also help in attaining more kinetic energy as compared to the bigger molecule (ethanol) at the same reaction temperature. The yield in Table-2 denotes the final reaction product obtained after the completion of the reaction between the magnesium metal and the mixture of alcohols (ethanol and methanol). As seen from Table-2, the magnesium alkoxide framework comprises 26 wt% to 27 wt% of magnesium, 18 wt% to 22 wt% of ethoxy and 45 wt% to 55 wt% of methoxy in the final product, when the ratio of methanol to ethanol is 50: 50.
The particle size analysis carried out for the magnesium alkoxide obtained in the experiments MME-0, MME-10, MME-50, MME-75 and MME-100 is presented in Figure-4 of the accompanying drawings. From the particle size distribution curves it is seen that the as the concentration of methanol is increased from 0 mole% to 100 mole%, the particle size distribution becomes broader. The particle size distribution is based on the span value calculated (Span = (D90-D10)/D50)). The higher value of the span corresponds to a broader particle size distribution. When the methanol: ethanol mole% is 50: 50 (Figure-4C), the mean particle size was found to be lower as compared to when the methanol mole% is increased (Figure-4D and E). A mean particle size in the range of 11 micrometer to 16 micrometer is observed when the magnesium: methanol: ethanol is 1: 6: 6 (Table-2 and Figure-4C). When the methanol mole% is increased to 100 % (Table-2 and Figure-4E), agglomeration of the magnesium alkoxide particles is observed.
Experiment 2:
The effect of the initiator concentration (amount of iodine) on the rate of reaction between the magnesium metal and the mixture of the alcohols (50/50 mole% of methanol and ethanol) was also studied. Table-3 below gives the different amounts of iodine used in the studies.

Table-3: Synthesis of material using the varied amount of iodine keeping the amount of other reagents constant
Mg-Metal Methanol Ethanol Initiator (I2 Mg : Methanol : Ethanol: I2 Methanol : Ethanol Charging
Experiment No. Amount Amount Amount Amount) Mole Ratio
g ml ml g Ratio in mole% Temp (°C)

(mole) (mole) (mole) (mole)
MME-I-0 2.75 g 25 ml 36 ml 0.0 g 1:6:6:0 50:50 15
(0.1 mole) (0.6 mole) (0.6 mole) 0

MME-I-75 2.75 g 25 ml 36 ml 0.75 g 1:6:6:0.003 50:50 15
(0.1 mole) (0.6 mole) (0.6 mole) 0.0003

MME-I-150 2.75 g 25 ml 36 ml 0.15 g 1:6:6:0.006 50:50 15
(0.1 mole) (0.6 mole) (0.6 mole) 0.0006

The magnesium alkoxide frameworks prepared by these experiments were named as MME-I-0, MME-I-75 and MME-I-150 when no iodine was used, when 75 mg of iodine was used and when 150 mg of iodine was used, respectively.
The rate of the reaction was studied by the comparison of the time-temperature profiles as presented in Figure-3 of the accompanying drawings. It is observed that the rate of reaction increases as the amount of the initiator increases as seen from the time-temperature profile of the reaction. When 150 mg of iodine was used, the time period for the lower temperature (15 °C) is very high (about 330 minutes), while the length of time period was only 180 minutes when iodine was not used. When 75 mg of iodine was used, the time period for lower temperature was observed to be 270 minutes. At higher concentration of iodine (150 mg), the amount of hydrogen evolved (observed as effervescences in the reaction mass) is prolonged for 330 minutes even at lower temperature (15 °C) and the reaction continues even at the low temperature. However, at low concentration of iodine, the reaction continued (evolution of hydrogen) for only 180 minutes, and the effervescences of hydrogen stopped after 180 minutes, indicating that the reaction had stopped. To continue (to carry out the reaction in the forward direction) the reaction after 180 minutes for completion, the temperature was increased for getting a similar amount of hydrogen evolution (rate of reaction). As previously mentioned, the temperature ramping frequency is related to the rate of reaction. Thus, the higher frequency of temperature ramps corresponds to a lower rate of reaction. When higher concentration of iodine was used (when 150 mg of iodine was used, temperature ramping was not required till 330 minutes of the reaction), the process was more energy efficient as additional energy in the form of heat was not required for ramping the temperature frequently.
The characteristics of the magnesium alkoxide framework obtained using different amount of iodine is given below in Table-4.

Chemical Composition Particle Size Analysis (µm) Surface Area Analysis
Methanol : Ethanol
Experiment No. Yield Surface Area Pore Volume
Ratio in mole% Mg Methoxy Ethoxy D10 D50 D90 Mean Span (D90-D10)/D50

Wt % wt% wt% g
m2/g cm3/g

MME-I-0 50:50 26.5 50 21 20.5 5 15 27 16 1.5 263 0.3

MME-I-75 50:50 26.3 53 19.5 20.5 4 9 24 11 2.2 266 0.29

MME-I-150 50:50 26.8 51 22 20.5 3 7 44 10 5.9 264 0.33
Table-4: Physico chemical characteristics of the magnesium alkoxide framework prepared using different amount of Iodine

D10, D50 and D90 – Particle size (diameter) of 10%, 50% and 90% particles.

From Table-4, it is seen that there is no significant change in the chemical composition and the surface area characteristics of the magnesium alkoxide framework when the amount of iodine was increased from 0 mg to 150 mg, and keeping the amount of magnesium, methanol and ethanol constant (methanol: ethanol ratio is 50: 50). The increased amount of iodine affects the rate of reaction as mentioned earlier.
The effect of iodine amount on the particle size and particle size distribution (PSD) is presented in Figure-5 of the accompanying drawings. It is seen that as the iodine concentration increases from 0 mg to 150 mg, the particle size of the magnesium alkoxide framework is reduced and the PSD becomes broader. The span value was calculated as previously mentioned, higher value of the span corresponds to a broader particle size distribution. When very high concentration of iodine (150 mg) was used, a corresponding high value of span was obtained, which may be due to the uneven packing of material in its lattice at very high rate of reaction which does not provide enough mechanical strength to the solid formed which ultimately breaks to generate particles during the agitation in the reaction mixture and results in broad distribution of the magnesium alkoxide particles.
Surface area and Morphological study
The surface area analysis was carried out for the powder sample of MME-0, MME-10, MME-50, MME-75 and MME-100. The relation between the amount of methoxy inserted in the product and the surface area is presented by Figure-6 of the accompanying drawings. It is seen that as the methoxy insertion increases from 0 wt% to about 50 wt%, the surface area increases from 10 m2/g to 265 m2/g. But when the methoxy content is further increased to more than 50 wt%, then the surface area is drastically reduced to 20 m2/g. The very large surface (about 270 m2/g) of the magnesium alkoxide framework was never reported earlier.
This is a completely new type of magnesium alkoxide framework with a relatively large surface area when the amount of methanol: ethanol is 50: 50. The relatively large surface area of magnesium alkoxide framework may be the result of fine tuning of the rate of the reaction between magnesium, methanol and ethanol which forms a material in which its lattice is highly porous due to the bonding between magnesium and methanol as well magnesium and ethanol. From the surface area and the pore volume, the magnesium mixed alkoxide framework fits in the category of mesoporous materials and truly in the category of metal organic framework.
The increase in the surface area of such frameworks from about 20 m2/g to 270 m2/g with increased content of methoxy in the material is surprising and the increase is 20 folds compared to the pure magnesium ethoxide. These types of phenomenon occur in case of supra molecular moiety or metal organic coordination network. The surface area remains unaffected when the initiator concentration was increased from 0 mg to 150 mg as seen from Table-4. This indicates that the chemical composition plays an important role to form this kind of framework which is highly porous in nature and gives relatively large surface area.
From Figure-7 of the accompanying drawings, it can be seen that the surface area isotherms forms a good hysteresis indicating the mesoporous structure of the material The shape of curve is also indicative of the types of pores. The shape indicates that the pores are formed from the stacking of flakes on each other. But this type of structure vanishes at higher and lower concentration of methanol as the shape of the isotherm changes with change in the methoxy insertion in the synthesized material.
Similar findings have been observed under the scanning electron microscope (SEM), as presented by Figure-8 of the accompanying drawings. At lower concentrations of methanol (Figures 8A and B), the surface of the particle remains smoother with stacking of irregular flakes on each other and has fewer amounts of surfaces to be exposed and hence, less surface area is observed. But when the amount of methanol was increased to 50 mole% (Figure-8C), the surface of the particle becomes rough and clear stacking of various flakes is formed on each other. The size of the flakes becomes uniform at 50 mole% of methanol and hence, the stacking also becomes uniform which creates uniform surfaces within the particle creating large surface area within the particle. However, when the amount of methanol mole% is further increased to 100 mole%, the surfaces of the particles again become smoother and fewer surfaces are created and hence, lower surface area is observed. When the amount of methanol mole% is increased up to 100 %, agglomeration with irregular particles is observed. From the surface area measurement (Table-2) and the SEM analysis (Figure-8), it is very clear that the magnesium alkoxide framework at 50 mole%, of methanol is a unique material and it is not a simple physical mixture of pure magnesium methoxide and pure magnesium ethoxide as both the pure material are showing very low surface area (Table-2).
Product Solubility study:
The solubility study was carried out to understand the nature of the magnesium alkoxide framework formed, when the amount of methanol was increased from 0 mole% to 100 mole%. The solubility test was carried out using methanol and ethanol as the fluid medium. In 100 ml two necked flask, 1 g of the synthesized material was taken and 100 g of the fluid medium was added to it and was stirred for 2 hours at room temperature (25 °C). After 2 hours of stirring the material was allowed to settle down and the supernatant liquid was decanted off and collected in a pre-weighed aluminium pan. The fluid medium was then evaporated by heating the solution till completely dry. The weight of the residues was calculated by differential weight of the aluminium pan, and the solubility was reported as the amount of soluble portion from the initial weight of the material.
The effect of fluid medium on solubility is presented in Figure-9 of the accompanying drawings. In this study, the results indicate that the commercial alkoxide (RELS) and the pure magnesium ethoxide are highly soluble in methanol by 5 wt% and 7 wt% respectively. However, pure magnesium methoxide is soluble to only 1 wt % to 2 wt% in methanol and ethanol. Also, pure magnesium ethoxide is soluble to only 1 wt % to 2 wt% in ethanol. This indicates that the magnesium alkoxide framework formed by mixed alcohol is not a simple physical mixture of pure magnesium methoxide and pure magnesium ethoxide, because the solubility observed for pure magnesium methoxide material is about 1 % to 2 % only, however, the solubility of pure magnesium ethoxide is 7 wt% in methanol and 1 wt % in ethanol. This confirms that the material formed is unique which is soluble to about only 1 wt% both in ethanol and methanol.
Comparative Experiment:
In this experiment, the effect of the methanol: ethanol (ratio in mole%) on the surface area of the magnesium alkoxide was studied. The ratio in mole% for methanol and ethanol used is given in Table-5 below. The spheroidal magnesium alkoxide of US8633124 having a ethoxy content in excess of the methoxy content was used for the comparative study. The surface area obtained for the magnesium alkoxide particles is summarized in Table-5.
Table-5
Methanol: Ethanol
(Ratio in mole%) Surface area (m2/g)
US8633124 (Example 1) Ethoxy content is in excess of the methoxy content 10
Present Disclosure 50:50 265

It is clearly seen from Table-5 that magnesium alkoxide framework having relatively large surface area is achieved when the amount of ethanol to methanol ratio is 50: 50. In the spheroidal magnesium alkoxide of US8633124, the ratio of magnesium to the mixture of alcohols is in the range of 1:2 to 1:20. Also, the amount of one of the alcohol is in excess amount of the other, preferably the ethoxy group is present in greater than 40 wt% of the total alkoxy content. Thus, the ratio of methanol to ethanol has a significant effect on the surface area as illustrated in Table-5.
The present disclosure provides a magnesium alkoxide framework having a relatively large surface area in the range of 200 m2/g to 270 m2/g and a pore volume in the range of 0.2 cm3/g to 0.35 cm3/g. The magnesium alkoxide framework having relatively large surface area may be used for preparing Ziegler-Natta pro-catalyst having large surface area. Such Ziegler-Natta pro-catalyst having large surface area may improve the polymerization performance of the catalyst. The magnesium alkoxide framework having relatively large surface area may be used as a carbon dioxide absorbent in the pharmaceutical industry and can also be used to store hydrogen in fuel cells.

TECHNICAL ADVANCES
- The present disclosure provides a magnesium alkoxide framework with relatively large surface area and pore volume.

- The large surface area magnesium alkoxide framework of the present disclosure can be used for preparing Ziegler-Natta pro-catalyst; the pro-catalyst is further used for preparing polymers.

The exemplary embodiments herein quantify the benefits arising out of this disclosure and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.