Claims:WE CLAIM:

1. A catalyst composition comprising:
a) a metallocene compound comprising at least one transition metal selected from Zr and Ti, wherein the concentration of said metallocene compound is in a range of 1-25 µmol with respect to the total weight of the catalyst;
b) a co-catalyst selected from at least one aluminium halide and at least one magnesium compound, wherein, a molar ratio of said metallocene compound to said aluminium halide is in the range of 1:40 to 1:300; and a molar ratio of said metallocene compound to said magnesium compound is in the range of 1:10 to 1:100; and
c) a donor free Grignard reagent, wherein a molar ratio of said metallocene compound to said donor free Grignard reagent is in the range of 1:5 to 1:150.
2. The catalyst composition as claimed in claim 1, wherein the metallocene compound is at least one selected from the group consisting of dicyclopentadienyl zirconium dichloride, dicycolpentadienyl titanium dichloride and 1-phenyl ethyl fluorenyl cyclopentadienyl zirconium dichloride.
3. The catalyst composition as claimed in claim 1, wherein the aluminium halide is at least one selected from the group consisting of ethyl aluminium chloride, methyl aluminium dichloride, diethyl aluminium chloride and dimethyl aluminium chloride.

4. The catalyst composition as claimed in claim 1, wherein the magnesium compound is at least one selected from the group consisting of di-ethyl magnesium, di-propyl magnesium, di-butyl magnesium, butyl ethyl magnesium, di-hexyl magnesium, di-decyl magnesium and di-dodecyl magnesium.
5. The catalyst composition as claimed in claim 1, wherein the donor free Grignard reagent is selected from the group consisting of dodecyl magnesium chloride, dodecyl magnesium bromide, decyl magnesium bromide and decyl magnesium chloride.
6. A process for preparation of a donor free Grignard reagent, said process comprising the following steps:
(i) mixing magnesium powder with iodine in a reactor under inert atmosphere to obtain a first mixture;
(ii) heating said first mixture until the iodine start to evaporate followed by adding a first predetermined amount of at least one alkyl halide in the reactor to obtain a second mixture;
(iii) adding at least one fluid medium and a second predetermined amount of said alkyl halide to said second mixture under inert atmosphere at a temperature in the range of 70oC to 120oC to obtain a reaction mixture;
(iv) refluxing said reaction mixture at temperature in the range of 120-130oC for 60-70 hours to obtain a product mixture comprising a clear solution of the donor free Grignard reagent and unreacted magnesium; and
(v) separating the clear solution from said product mixture to obtain the donor free Grignard reagent having a concentration in the range of 0.20 to 0.30 mol/litre.
7. The process as claimed in claim 6, wherein a heat gun is used for heating the first mixture.
8. The process as claimed in claim 6, wherein, the alkyl halide is at least one selected from the group consisting of dodecyl chloride, dodecyl bromide, decyl bromide and decyl chloride.
9. The process as claimed in claim 6, wherein, the first pre-determined amount of the alkyl halide is in the range of 20-40% of total weight of the alkyl halide and the second pre-determined amount of the alkyl halide is in the range of 80-60% of the total weight of the alkyl halide.
10. The process as claimed in claim 6, wherein the fluid medium is toluene.
11. A process for preparation of a catalyst composition, said process comprising the following steps:
a. mixing at least one metallocene compound in a fluid medium followed by adding at least one co-catalyst at a temperature in the range of 10 to 25oC under stirring to obtain a mixture; and

b. adding at least one donor free Grignard reagent to said mixture and allow to react for a time period in the range of 2 minutes to 10 minutes at a temperature in the range of 10 to 25oC under stirring to obtain the catalyst composition.
12. The process as claimed in claim 11, wherein the metallocene compound is at least one selected from the group consisting of dicyclopentadienyl zirconium dichloride, dicyclopentadienyl titanium dichloride and 1-phenyl ethyl fluorenyl cyclopentadienyl zirconium dichloride.
13. The process as claimed in claim 11, wherein the co-catalyst is selected from ethylene aluminum dichloride (EADC), diethyl aluminum chloride (DEAC), and dialkyl magnesium (DAM).

14. A polymer obtained by using the catalyst composition as claimed in claim 1, has a crystallinity in the range of 5% to 95%.
, Description:FIELD
The present disclosure relates to a catalyst composition and a process for preparation thereof.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Metallocene compound: The term “metallocene compound”, also known as single site catalyst (SSC) refers to an organometallic compound with a sandwich like spatial arrangement, consisting of a transition metal situated between two cyclic organic compounds. A common example of metallocene compound is Zirconocene which consists of zirconium ion sandwiched between two cyclopentadienyl ligands.
Donor free Grignard reagent: is an organometallic compound with generic formula R-Mg-X, wherein X is halogen and R is alkyl or aryl group, and is devoid of the solvent such as tetrahydrofuran and di-ethyl-ether containing electron donating groups.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Metallocene compound with a co-catalyst is known in the art for their use in polymerisation of olefins. Typically, a co-catalyst is required for activating the metallocene catalyst. The co-catalyst generally comprises an aluminium compound and a magnesium compound. Hence, the catalyst composition comprises a metallocene compound which is a transition metal complex with a bi-dentate or tri-dentate ligand and a co-catalyst mixture containing dialkyl aluminium halide and dialkyl magnesium. Further, the conventional catalyst composition comprising a silica supported metallocene catalyst complicates, the process for preparation of catalyst composition.
Metallocene catalyst typically also requires a co-catalyst such as aluminoxane and borane compounds for the activation. Aluminoxane and borane compounds are expensive and hence the use of catalyst composition containing such co-catalyst is not economical. Further, metallocene catalyst includes support material which makes the process of catalyst preparation complicated.
Further, in the conventional processes, to adjust density or crystallinity of polymers, co-monomer is commonly used and polymer/homopolymer with wide range of crystallinity cannot be produced using the conventional catalyst composition. Therefore, co-monomers like 1-butene and 1-hexene are commonly used during polymerization process for adjusting density or crystallinity of the polymer.
Therefore, there is felt a need for a simple and less expensive catalyst composition for producing polymers with a wide range of crystallinity without the use of co-monomers.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a catalyst composition.
Another object of the present disclosure is to provide a simple process for the preparation of the catalyst composition.
Yet another object of the present disclosure is to provide a homopolymer with wide ranging crystallinity by using the catalyst composition without the addition of co-monomers.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a catalyst composition comprising a metallocene compound having at least one transition metal selected from Zr or Ti, wherein the concentration of the metallocene compound is in a range of 1-25 µM with respect to the total weight of the catalyst; a co-catalyst is at least one selected from an aluminum halide and at least one magnesium compound, wherein a molar ratio of the metallocene compound to the aluminium halide ranges from 1:40 to 1:300 and a molar ratio of the metallocene compound to the magnesium compound ranges from 1:10 to 1:100; and a donor free Grignard reagent wherein a molar ratio of the metallocene compound to the donor free Grignard reagent ranges from 1:5 to 1:150.
The present disclosure also relates to a process for preparation of a donor free Grignard reagent. The process comprises mixing magnesium powder with iodine in a reactor under inert atmosphere to obtain a first mixture. The reactor is heated until the iodine start to evaporate followed by adding a first predetermined amount of at least one alkyl halide in the reactor to obtain a second mixture. At least one fluid medium and a second predetermined amount of at least one alkyl halide is added to the second mixture under inert atmosphere at a temperature in the range of 70oC to 120oC to obtain a reaction mixture. The reaction mixture is refluxed at a temperature in the range of 120oC to 130oC for 60 hours to 70 hours to obtain a product mixture comprising a clear solution of the donor free Grignard reagent and unreacted magnesium. The clear solution comprising the donor free Grignard reagent is separated from the product mixture to obtain the donor free Grignard reagent having a concentration in the range of 0.20 to 0.30 mol/litre.
The present disclosure further relates to a process for preparation of a catalyst composition. The process comprises mixing at least one metallocene compound in a fluid medium followed by adding at least one co-catalyst at a temperature in the range of 10 to 25oC under stirring to obtain a mixture. At least one donor free Grignard reagent is added to the mixture and allowed to react for a time period in the range of 2 minutes to 10 minutes at a temperature in the range of 10 to 25oC under stirring to obtain the catalyst composition. The present disclosure also relates to the polymers obtained by using the catalyst composition, which have crystallinity in the range of 5% to 95%.
DETAILED DESCRIPTION
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Metallocene catalyst typically require co-catalyst such as aluminoxane and borane compounds for the activation. Aluminoxane and borane compounds are expensive and hence the use of catalyst composition containing such co-catalyst is not economical. Further, metallocene catalyst includes support material which makes the process of catalyst preparation complicated. Further, the conventional catalyst composition used in the polymerization processes require use of trichloro fluoromethane or dibromomethane as promotors.
Still further, in the conventional processes, to adjust density or crystallinity of polymers, co-monomer is commonly used and homopolymer with wide range of crystallinity cannot be produced using the catalyst composition.
The present disclosure provides a catalyst composition which solves the problem mentioned herein above and also provides polymers having a wide range of crystallinity.
In an aspect, the present disclosure provides to a catalyst composition comprising a metallocene compound having at least one transition metal selected from Zr or Ti, wherein the concentration of the metallocene compound is in a range of 1-25 µM; a co-catalyst is at least one selected from an aluminum halide and at least one magnesium compound, wherein a molar ratio of the metallocene compound to the aluminium halide ranges from 1:40 to 1:300 and a molar ratio of the metallocene compound to the magnesium compound ranges from 1:10 to 1:100; and a donor free Grignard reagent wherein a molar ratio of the metallocene compound to the donor free Grignard reagent ranges from 1:5 to 1:150. The “metallocene compound”, also known as single site catalyst (SSC) refers to an organometallic compound with a sandwich like spatial arrangement, consisting of a transition metal situated between two cyclic organic compounds. A common example of metallocene compound is Zirconocene which consists of zirconium ion sandwiched between two cyclopentadienyl ligands.
In accordance with the present disclosure, the metallocene compound is typically chosen from dicylcopentadienyl halide with a transition metal or a fluorenyl cyclopentadienyl halide with a transition metal. The metallocene compound is at least one selected from the group consisting of dicyclopentadienyl zirconium dichloride, dicycolpentadienyl titanium dichloride and 1-phenyl ethyl fluorenyl cyclopentadienyl zirconium dichloride. In an exemplary embodiment, metallocene compound is dicyclopentadienyl zirconium dichloride.
The concentration of the metallocene compound is in the range of 1-25 µmol with respect to the total weight of the catalyst. In an exemplary embodiment, the concentration of the metallocene compound is in the range of 1-15 µmol.
In accordance with the present disclosure, the co-catalyst is at least one selected from an aluminium compound and at least one selected from a magnesium compound. The aluminium compound is at least one selected from ethyl aluminium dichloride, methyl aluminium chloride, diethyl aluminium chloride and dimethyl aluminium chloride. A molar ratio of the metallocene compound to the aluminium compound is in the range of 1:40 to 1:300. In an exemplary embodiment, aluminium compound is diethyl aluminium chloride and the molar ratio of the metallocene compound to the diethyl aluminium chloride is 1:50. In another embodiment, the molar ratio of the metallocene compound to the diethyl aluminium chloride is 1:240.
The magnesium compound is at least one selected from diethyl magnesium, di-propyl magnesium, di-butyl magnesium, butyl ethyl magnesium, di-hexyl magnesium, di-decyl magnesium, and didodecyl magnesium. A molar ratio of the metallocene compound to the magnesium compound is in the range of 1:10 to 1:100. In an exemplary embodiment, the magnesium compound is n-butyl sec-butyl magnesium and the molar ratio of the metallocene compound to the n-butyl didodecyl magnesium compound is 1:15 and in another embodiment, the molar ratio of the metallocene to the magnesium compound is 1:70.
The donor free Grignard reagent is at least one selected from a group consisting of dodecyl magnesium chloride, dodecyl magnesium bromide, decyl magnesium bromide and decyl magnesium chloride. In an exemplary embodiment, the donor free Grignard reagent is dodecyl magnesium bromide and the molar ratio of the metallocene compound to dodecyl magnesium bromide is 1:140.
In an embodiment of present disclosure, the molar ratio of the metallocene catalyst to the magnesium compound to the aluminium compound to the donor free Grignard reagent is 1:40:100:15
Commercial Grignard reagent generally contains substantial amount of donor compounds. Typical donor compounds that are used to stabilize Grignard reagents are tetrahydrofuran (THF) and di-ethyl ether (DEE). However, the donor compounds inhibit the activity of typical metallocene compounds and therefore, are not used in catalytic composition with metallocene compounds.
The present disclosure provides a process for preparation of a stable donor free Grignard reagent that forms a part of the metallocene catalyst composition.
The process comprises mixing magnesium powder with iodine in a reactor under inert atmosphere to obtain a first mixture. The reactor is heated until the iodine starts to evaporate followed by adding a first predetermined amount of at least one alkyl halide in the reactor to obtain a second mixture. At least one fluid medium and a second predetermined amount of at least one alkyl halide is added to the second mixture under inert atmosphere at a temperature in the range of 70oC to 120oC to obtain a reaction mixture. The reaction mixture is refluxed at a temperature in the range of 120oC to 130oC for 60 hours to 70 hours to obtain a product mixture comprising a clear solution of the donor free Grignard reagent and unreacted magnesium. The clear solution comprising the donor free Grignard reagent is separated from the product mixture to obtain the donor free Grignard reagent having a concentration in the range of 0.20 to 0.30 mol/litre.
In accordance with the present disclosure, the donor free Grignard reagent is obtained by reacting magnesium powder, iodine crystals and alkyl halide in a donor free solvent in an inert atmosphere at a temperature in the range of 70oC to 120oC, for a time period in the range of 60-70 hours. Donor free solvent is degassed toluene.
The present disclosure further relates to a process for preparation of a catalyst composition The process comprises mixing at least one metallocene compound in a fluid medium followed by adding at least one co-catalyst at a temperature in the range of 10 to 25oC under stirring to obtain a mixture. At least one donor free Grignard reagent is added to the mixture and allows reacting for a time period in the range of 2 minutes to 10 minutes at a temperature in the range of 10 to 25 oC under stirring to obtain the catalyst composition.
In accordance to the embodiments of the present disclosure, the polymers obtained by using the catalyst composition of the present disclosure have crystallinity in the range of 5% to 95%. In an embodiment, the crystallinity of polymer obtained is 68.5%.
The present disclosure also provides technical advancement in terms of providing a stable donor free Grignard reagent and a process of obtaining a donor free Grignard reagent. Unlike a typical Grignard reagent stabilized by the donor compounds, the donor free Grignard reagent of the present disclosure is included in the catalyst composition. The polymers obtained by employing the catalyst composition of the present disclosure, have wide ranging crystallinity. Co-monomers are generally used for adjusting crystallinity of polymers. Use of donor free Grignard reagent in the catalyst composition allows obtaining polymers with wide range of crystallinity without the use of co-monomers.
The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure and all such modifications are considered to be within the scope of the present disclosure.
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. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Experiment 1: Preparation of donor free Grignard reagent
Oven dried magnesium powder (1.337 g; 55 mmol) was weighted into a 3-necked 100 ml round-bottomed reactor. The flask was connected to an argon gas line, a dropping funnel and a reflux condenser. The reflux condenser was further connected to a mercury-trap, which eliminated the possibility of a gas flow from the environment into the reactor. 2 mg. of iodine crystals of were added into the magnesium powder. The whole reactor system was flushed with a stream of argon gas creating totally inert conditions. The magnesium powder and iodine crystals were heated for 2 minutes with a heat-gun until the iodine started to evaporate as a violet gas. 1-bromododecane (3.6 ml; 15 mmol) was then introduced together with 50 ml of toluene from the dropping funnel into the reactor.
50 ml of dry and degassed toluene was then introduced in inert conditions into the dropping funnel together with the rest of the 1-bromododecane (8.4 ml; 35 mmol). The solution of toluene and 1-bromododecane was added drop wise into the reactor containing a similar amount of pre-heated magnesium and iodine. The temperature was kept at 90°C. After the addition was completed, the temperature was increased to the reflux temperature of toluene (~125°C). The reaction was allowed to continue for a period of about 66 hours. A clear liquid (donor free Grignard reagent) resulted with a layer of dull-gray un-reacted magnesium settled at the bottom. The clear liquid was analyzed in respect of its Mg and Br content in order to define the strength of the Grignard solution. Concentration of this solution was 35 mmol/58 ml (0.6 M).
Experiment 2: Preparation of catalyst composition
100 micromole of dicyclopentadienyl Zr dichloride complex was mixed in 10 ml. A pre-determined amount of a co-catalyst and a donor free Grignard reagent was added at a temperature of 10oC to obtain a reaction mixture. The pre-determined amounts are illustrated in table 1. The reaction mixture so obtained was allowed to react for a period of 5 minutes to obtain the catalyst composition.
Experiment 3: Ethylene polymerization using the in-situ generated catalyst composition
Autoclave was loaded with 200 ml of toluene. 3.0 bar of ethylene monomer gas was introduced into autoclave. Total pressure was maintained at 4 bar with the use of argon gas. The temperature in the autoclave was adjusted to 50oC.
First 10 µmol of metallocene was injected together with 0.27 ml (500 µmol) of diethyl aluminum chloride (DEAC). After that 0.285 ml (200 µmol) of n-butyl-sec-butyl magnesium (DAM) with 2 ml dodecyl-magnesium-bromide were added to the reactor. Thus the molar ratio of metallocene compound: DAM: DEAC is 1:15:50:55 in this polymerization set up. The compositions are illustrated in Code RY029 in table 1,2,3 and 4.
Polymerization was stopped after 50 min by transferring the toluene-polyethylene slurry into a vessel containing 300 ml of methanol and 3 ml of 10 % HCl. The results are summarized in table 1, table 2, table 3 and table 4.
Experiment 4: Ethylene polymerization using catalyst composition Cp2ZrCl2, DAM and a donor free Grignard reagent.
Ethylene polymerization as described in experiment 3 was also used for carrying out experiment 4 except the variation in amounts such as 22 µmol of Cp2ZrCl2, 1.6 ml of DAM and 0.5 ml of donor free Grignard reagent was used. The ethylene polymerization is carried out in the presence of catalyst composition which was devoid of aluminium halide.
Experiments 5-11: Ethylene polymerization using various catalyst compositions
Ethylene polymerization was carried out similar to the process as given in experiment 3 with various catalyst compositions as given in Table 1, 2, and 3.
Table 1. Catalyst composition
Code SSC SSC
(µmol) MAO
(ml) DAM2
(ml) EADC
(ml) DEAC3
(ml) Grignard4
(ml)
RY018
RY020
RY027
RY028
RY029
RY030
RY032
RY033
RY037
RY040
RY045
RY047 Cp2ZrCl2
Cp2ZrCl2
Cp2ZrCl2
Cp2ZrCl2
Cp2ZrCl2
SSC1
Cp2ZrCl2
Cp2ZrCl2
Cp2TiCl2
Cp2TiCl2
Cp2TiCl2
Cp2TiCl2
22
100
10
10
10
2.0
3.0
10
10
10
10
10 -
-
-
-
-
-
3.0
-
-
-
-
- 1.6
11.4
2.9
0.4
0.2
0.2
-
0.3
2.9
1.432
4.76
7.14 -
8.0
-
-
-
-
-
-
-
-
-
- -
-
4.08
0.54
0.27
0.27
-
0.54
4.08
4.08
5.443
8.16 0.5
-
-
0.5
2.0
1.0
-
3.0
-
-
-
-
1) SSC = 1-Phenyl-Ethyl-Flu-Cp-ZrCl2
2) 1.43 ml DAM corresponds to 1000 µmol DAM (0.7 M)
3) 5.44 ml DEAC corresponds to 10000 µmol DEAC (1.8 M)
4) Donor free Grignard was 0.28 M

Codes (RY018, RY020, RY027-RY030, RY032- RY033, RY037, RY040, RY045, RY047) in the first column represents catalyst composition used for polymerization of ethylene.
RY018 catalyst composition comprises single site compound (SSC) or the metallocene compound, dicyclopentadienyl zirconium dichloride (Cp2ZrCl2) with a concentration of 22 µmol, dialkyl magnesium (DAM) 1.6 ml and donor free Grignard reagent 0.5 ml.
RY020 catalyst composition additionally contains ethylene aluminium dichloride (EADC) in addition to ingredients enumerated in RY018.
The composition represented by code RY030, comprises metallocene catalyst 1-phenyl ethyl fluorenyl cyclopentadienyl zirconium dichloride (SSC1), dialkyl magnesium (DAM), diethyl aluminium chloride (DEAC) and donor free Grignard reagent.
RY032 represents a reference sample comprising Cp2ZrCl2 and methyl aluminoxane (MAO).
Table 2 illustrates that in case of RY020, RY040, RY045 and RY047, where catalyst composition does not include donor free Grignard reagent, crystallinity range of polymer prepared was shown to high (82% to 88%). Thus, polymer obtained with catalyst composition, devoid of donor free Grignard reagent, has high crystallinity.
Three samples RY018, RY028 and RY033, wherein additionally donor free Grignard reagent is present in addition to catalyst composition in any of the samples described herein above which gave high crystallinity polymers, produced polymers with crystallinity values recorded as 8.5%, 72.81% and 68.5% respectively.
Other catalyst composition with donor free Grignard reagent represented by code RY029 and RY030 produced polymers with crystallinity range of 66.76% and 79.43% respectively. Thus, with the addition of donor free Grignard reagent, depending on the concentration of donor free Grignard reagent, polymers of wide ranging crystallinity are obtained.
Table 2. Melting point and crystallinity of polyethylene polymers

Code Melting point (oC) Crystallinity (%) Remarks
RY018
RY020
RY027
RY028
RY029
RY030
RY033
RY040
RY045
RY047 126.09
131.22
130.71
131.78
135.48
132.93
134.2
130.41
131.52
129.36
8.5
82.0
44.7
72.81
66.76
79.43
68.5
85.8
85.7
88.83 Very broad melting peak
Very sharp melting peak
Lower crystallinity
Medium crystallinity
Medium crystallinity
Medium crystallinity
Medium crystallinity
Sharp melting peak
Very sharp melting peak
Very sharp melting peak

Table 2 illustrates melting points and crystallinity of polymers obtained with various catalyst compositions.
Table 3. Polymer yield and activity

Code Polymerization time (h) Yield
(g) Activity1 (kg PE/mol,h) Molar
ratio3 Comment
RY018
RY020
RY027
RY028
RY029
RY030
RY032
RY033
RY037
RY040
RY045
RY047 Short
0.72
0.38
0.32
0.84
1.15
0.33
0.27
0.61
0.50
0.50
0.50 Small
5.15
4.96
3.33
0.473
0.588
6.95
0.771
2.01
1.313
2.635
3.062 Low
71.5
1301
1034
559
255
4366
29.7
328
263
527
612 1:50:6
1:17:870
1:200:750
1:40:100:15
1:15:50:55
1:70:240:140
1:700
-
-
-
-
- Low activity
Low activity
Medium act.
Medium act.
Low activity
Low activity
Reference
Deactivated2
Cp2TiCl2 , Catalyst
Low activity
Low activity
Low activity
1) Activity as kg PE/ mol transition metal per hour
2) Deactivated in 16 min.
3) Molar ratio between SSC/DAM/DEAC/donor free GR
The table 3 illustrates polymerization time, yield, and activity based on the catalyst composition.
RY032 is a reference catalyst sample using a co-catalyst aluminoxane with the metallocene compound. Reference sample shows an activity of 4366 kgs of polyethylene formation / mol transition metal of metallocene compound per hour. Polymerization time is 0.33 hours and polymer yield is 6.95 gms. However, reference sample represented by RY032 has not been considered for comparison purposes as the catalyst composition is different from other samples. None of the catalyst compositions other than RY032 comprises aluminoxane.
Code RY027 comprises a metallocene catalyst, dialkyl magnesium and diethyl aluminium chloride. Samples represented by codes RY018, RY028, RY029, RY030 and RY033 additionally contain donor free Grignard reagent in addition to the ingredients of the catalyst composition in sample code RY027.
Thus RY027 composition is considered as standard prior art composition. Yield and activity of catalyst composition RY028 was comparable to standard prior art catalyst composition ingredients RY027. Polymer produced in RY033 was deactivated in 16 minutes.
Table 4. Comparison of the polymerization results where a Grignard component has been added to the polymerization to standard results achieved with “standard prior art”.

Polymerization code Grignard (ml) Activity1 Crystallinity (%)
“Standard prior art”
RY028
RY029
RY030
RY033
Max Grignard (RY018) 0
0.5
2.0
1.0
3.0
Max 1301
1034
559
255
30
1-2 85-89
72.81
66.76
79.43
68.5
8.5
1) Activity as kg PE/ mol transition metal per hour

The results of table 1, 2 and 3 are summarized in Table 4, which illustrates that a polymer obtained with a standard prior art catalyst composition comprising a metallocene compound and a co-catalyst, dialkyl magnesium and diethyl aluminium chloride, as represented by RY027, crystallinity of polymer generally ranges from 85-89%. It is further illustrated in table 4 that samples RY028, RY029, RY030, RY033 and RY018, additionally comprise a donor free Grignard reagent in varying amounts, in addition to ingredients of catalyst composition of RY027. It is illustrated that the crystallinity of polymers obtained with the addition of Grignard reagent varies with varying amounts of donor free Grignard reagent. Polymerization experiment represented by RY018 was carried out wherein diethyl aluminium chloride is left out and the catalyst comprises a metallocene compound and dialkyl magnesium and a donor free Grignard reagent (0.5ml). This test could be regarded as a polymerization test wherein molar ratio of Grignard reagent to diethyl aluminium chloride represents a maximum value as illustrated in table 4 and is labelled as Max Grignard. Though the activity is low, crystallinity of polymer drops to 8.5% in case of RY018. Activity for polymerization process drops to close to zero and therefore, depicts that use of aluminium compound is essential to the catalyst composition for polymerization process.
As the crystallinity value in polymer is normally in direct proportion to the density of the polymer this drop in crystallinity should corresponds to a similar kind of drop in density of the material. This material is still a homopolymer polyethylene material.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to the realization of a catalyst composition that exhibits:
- stability of the catalyst composition comprising metallocene catalyst, a co-catalyst and a donor free Grignard reagent;
- a process for preparation of a catalyst composition which is simple and economical;
- production of homopolymers having a wide range of crystallinity
The catalyst composition described herein above allows controlling crystallinity of polymer without adding a co-monomer.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure 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.