Title of Invention

A PROCESS FOR THE PREPARATION OF FERROCENE POLY GLYCOL OLIGOMER

Abstract This invention relates to a process for the preparation of ferrocene polyglycol oligomer (FPGO) comprising the steps of preparing diacetyl ferrocene by synthesising diacetyl ferrocene by reacting ferrocene, acetyl chloride & AICI3 preferably in the mole ratio of 1:2.6-2.8:2.4-3, respectively, by adding acetyl chloride drop wise at 20-30°C within 30-40 minutes, adding ferrocene to this solution under continuous stirring while maintaining the temperature to 20-30°C, pouring the said reactants over ice and purifying the crude obtained by recrystallisation in cyclohexane; preparing bis (hydroxy ethyl) ferrocene from the said diacetyl ferrocene obtained from step (a) by reducing 0.1-0.2 M of diacetyl ferrocene completely to bis (hydroxy ethyl) ferrocene with 0.7-0.8 M sodium borohydride in 12-16 M isopropanol, at 70-90°C and recrystallising the product in n-heptane copolymerising the said bis (hydroxy ethyl) ferrocene and 1,4 butane diol by condensing the said bis (hydroxy ethyl) ferrocene and bis (hydroxy ethyl) ferrocene using boron trifluoride etherate to obtain ferrocene polyglycol oligomer (FPGO).
Full Text FIELD OF INVENTION:
The present invention relates to a process for the preparation of Ferrocene Poly Glycol Oligomer (FPGO). PRIOR ART :
High burning rate composite propellants are needed for futuristic programs, particularly in surface to air mission to reduce the operational time of the missiles. Commonly used ballistic modifiers, such as ferric oxide or copper chromite do not meet these objectives as their addition, beyond an optimum limit, leads to high end-of- propellant mix viscosity.
During recent times, liquid ferrocenes such as n-butyl ferrocene and catocene are getting attention as ballistic modifiers due to their plasticisation capability. These catalysts not only overcome the problem of high end-of-propellant mix viscosity but also allow a high level of solid (oxidizer and metal fuel) fillers, resulting in superior ballistics.
One of the severe drawbacks of these ferrocenes, known in the prior art, is that they migrate out of the propellants resulting in change in composition of the propellant.
Yet another disadvantage of these ferrocenes, known in the prior art, is that these come in contact with liners and insulators and, thereby, adversely affecting the pre-programmed combustion pattern.
Still another disadvantage of these ferrocines is that when used as ballistic modifiers, these result in the formation of aerosol during processing due
to high volatility thereby posing fire hazards in presence of ammonium perch lorate
In order to overcome migration problem, the recent approach, known in the prior art, involves chemical grafting of ferrocene catalyst on HTPB binder. This grafted pre polymer is referred as ' Butacene'. The burning rates of Butacene based propellants are comparable to those incorporating traditional non bonded ferrocenes like n-butyl ferrocene. However, these butacenes, already known in the art, also suffer from disadvantages.
The major problem of "Butacene' is that its synthesis is tedious involving several steps. The first step involves the preparation of organosilicon ferrocene derivative like Fc-R-Si H(CH3)2 ( R= alkyl or phenyl group),where reaction conditions & work up is critical due to susceptibility of silicon derivative to moisture resulting in decomposition. In the second step, organosilicon ferrocene obtained is added to hydroxy terminated polybutadiene (HTPB) through hydrosilation reactions in presence of a "Platinum" based catalyst. The process is cost intensive due to platinum based catalyst and lower yields. OBJECTS OF THE INVENTION :
Primary object of the invention is to provide a process for the preparation of Ferrocene Poly, Glycol Oligomer (FPGO) from bis (hydroxy ethyl) ferrocene and 1,4 butane diol.
Another object of the invention is to provide a process for preparation of composite propellant incorporating FPGO of the present invention which does not suffer from aerosol formation and migration.
Yet another object of the invention is to provide a process for the preparation of Ferrocene Poly Glycol Oligomer (FPGO), which does not migrate to the surface of propellant.
Yet further object of the invention is to provide a process for the preparation of FPGO which forms the backbone of the polymer and which does not get oxidised.
Yet another object of the invention is to provide a process for the preparation of Ferrocene Poly Glycol Oligomer (FPGO), which is nonvolatile.
Still another object of the invention is to provide a process for the preparation of Ferrocene Poly Glycol Oligomer (FPGO), which is liquid with better thermal stability.
Yet further object of the invention is to provide a process for the preparation of Ferrocene Poly Glycol Oligomer (FPGO), which is miscible with HTPB binder.
DESCRIPTION OF THE INVENTION:
According to this invention there is provided a process for the preparation of ferrocene polyglycol oligomer (FPGO) comprising the steps of:
a) preparing diacetyl ferrocene by synthesising diacetyl ferrocene by reacting ferrocene, acetyl chloride & AICI3 preferably in the mole ratio of 1:2.6-2.8:2.4-3, respectively, by adding acetyl chloride drop wise at 20-30°C within 30-40 minutes, adding ferrocene to this solution under continuous stirring while maintaining the temperature to 20-30°C, pouring the said reactants over ice and purifying the crude obtained by recrystallisation in cyclohexane;
b) preparing bis (hydroxy ethyl) ferrocene from the said diacetyl ferrocene obtained from step (a) by reducing 0.1-0.2 M of diacetyl ferrocene completely to bis (hydroxy ethyl) ferrocene with 0.7-0.8 M sodium borohydride in 12-16 M isopropanol, at 70-90°C and recrystallising the product in n-heptane;
c) copolymerising the said bis (hydroxy ethyl) ferrocene and 1,4 butane diol by condensing the said bis (hydroxy ethyl) ferrocene and bis (hydroxy ethyl) ferrocene using boron trifluoride etherate to obtain ferrocene polyglycol oligomer (FPGO).
of the present invention has hydroxyl end-groups having following structural formula.

(Formula Removed)
The process for the preparation of ferrocene compound comprises of following steps. (i) Preparing diacetyl ferrocene
In the first step, diacetyl ferrocene is synthesised. The Synthesis involves reaction of ferrocene, acetyl chloride & AlCl3 preferably in the mole ratio of 1: 2.6-2.8: 2.4 -3, respectively, in suitable solvent. Initially, acetyl chloride is added drop wise to AICI3at about 20-30°C within 30-40 minutes. Next, ferrocene is added to this solution under continuous stirring while maintaining the temperature to 23-27 °C. Subsequently, the contents are poured over crushed ice and the crude product obtained is purified by recrystallisation in cyclohexane. (ii) Preparing Bis ( hvdroxy ethyl) ferrocene (BHEF)
0.1 - 0.2 M of diacetyl ferrocene, obtained from step (i), is reduced completely to bis (hydroxy ethyl)ferrocene with 0.7- 0.8 M sodium borohydride
in 12 - 16 M isopropanoi. Diacetyle ferrocene is added to sodium borohydride and the mixture is heated to 75-85°C under continuous stirring for about 2 hours. The product obtained is recrystallised in n-heptane. (iii) Co-polvmerising bis (hvdroxv ethyl) ferrocene (BHEF) with 1,4 butane diol
Bis (hydroxy ethyl)ferrocene, obtained from step (ii) is copolymerised with 1,4 butane diol by condensing 0.1 - 0.2 M bis hydroxy ethyl ferrocene with 0.5 -0.6 M of 1,4butane diol, under nitrogen, in presence of 0.003 - 0.005 M boron trifluoride etherate (in 10 -15 cc of diethyl ether) at a temperature of 25-30°C to give FPGO Preparation of Propellant Formulation incorporating FPGO
The compound, finally obtained, is incorporated in AP based composite propellant composition by adopting slurry cast technique. The preparation of propellant incorporating Ferrocene poly glycol oligomer (FPGO) comprises of following steps :-
a) Mixing of Binder components
The binder (15-20%) comprising HTPB and dioctyl adipate (DOA) in (60:40) ratio, crosslinker pyrogall (0.25-.35%) cured with toluene diisocyanate(TDI) NCO:OH-(1:1.5-1:1) and lecithin(process aid) (0.3%) are mixed in a planetary mixer along with FPGO (0.3%) for 10-20 min at 60 ± 2°C to obtain a uniform slurry.
b) Mixing of Ammonium Perchlorate
Slurry obtained in step (a) is deaerated by applying vacuum of the order of 5-10 torr at 60 + 2°C under stirring and bimodal AP of 250 M. size (50 - 55%) and
8-10µ size (30 - 35%) or monomodal AP of 8-9 LI, (80 - 90%AP (coarse) and AP (fine) are added preferably in small installments to the slurry and mixing is continued for 30-40 min at 60 ± 5°C . Subsequently, slurry temperature is brought down to c) Mixing of toluene di-isocyanate
toluene di-isocyanate is added to the slurry obtained in Step (b ) and mixing is continued at 45 ± 5°C in conditioned room with RH d) Casting of the slurry
Casting of the slurry obtained by step (c) above is carried out in a mould, evacuated to 2-5 torr. The vacuum is released and the mould is transferred to a water jacketed oven maintained at 55 ± 5°C and is allowed to cure for 7-8 days. This invention will now be illustrated with a working example which is intended to be a typical example to explain the working of the present invention and is not intended to be taken restrictively to imply any limitation in the scope of the present invention. Working Example-1 (i) Preparation of diacetvl ferrocene (DAF)
To 192 g of AICI3 in 730cm3 of dichloromethane, 123 cm3 of acetyl chloride was added drop wise at ~25°C within 30 to 40 min. A solution of 112 g of ferrocene in 375 cm3 of dichloromethane was added to this solution under
stirring within 25 min while maintaining temperature of 25 + 5°C by using chilled water bath. Stirring was continued for 2 hours at 25 ± 5°C. Then the contents were poured on crushed ice with stirring. The organic layer was separated . Aqueous layer was extracted with 1800 cm3 (600 cm3 x 3) of dichloromethane. The dichloromethane extract was mixed with organic layer obtained earlier and contents were concentrated to 600 cm3. 300 cm3 of chloroform was added to the concentrate and solution poured in 1000 cm3 of cyclohexane all at once, filtered and kept in ice bath. The yield was 95-100 g (55 to 65 %). (ii) Preparation of Bis (hvdroxy ethyl) ferrocene (BHEF)
To 29.7 g of sodium borohydride in 812 cm3 of isopropanol, 65 g of diacetylferrocene was added. The mixture was heated to 80 ± 5°C under stirring for 2 hours. 670 ±10 cm3 of isopropanol was recovered by distillation. After cooling to ambient temperature, 325 cm3 of 15% sodium chloride solution was added and stirred well for one hour. The contents were extracted with 725 cm3 of dichloromethane. Extract was washed with 100 cm3 of 15% aqueous solution of sodium chloride and dried on anhydrous sodium sulphate. Solvent was evaporated to dryness. 63 g of crude BHEF was collected and recrystallised in n-heptane. The yield was 55 - 60 g (80 to 90 %). (iii) Preparation of Ferrocene polvglvcol oligomer (FPGO)
50 g of BHEF and 50 cm3 of 1,4 butane diol were stirred together under nitrogen atmosphere, at 25 ± 4°C temperature. To this, 0.3 cm3 of boron tri fluoride etharate in 10 cm3 diethyl ether was added drop wise. Stirring was
continued for two hours at 25 ± 5°C temperature and , then for one hour at 40 to 45°C. The contents were allowed to cool.
200 cm3 each of dichloromethane and water were added to the reaction mixture kept under stirring. Organic layer was separated and washed three times with 200 cm3 of 2% aqueous solution of sodium bicarbonate. The solvent was evaporated under vacuum and crude FPGO was collected. The yield was 65 g (85 to 90 % ). FPGO was further purified by precipitating it with petroleum ether (60 - 80°C). The final yield was 45 - 50 g.
The characteristics of the FPGO, prepared from the process of the present invention, has been provided in the following:
Number average molecular weight (~Mn ) of FPGO 700 ± 40
Hydroxyl equivalent 0.029 to 0.033 eq/kg
Iron content 16 ±1 % .
Density 1.23± 0.03 g/cm3
Viscosity 4650 ± 100 cPS (at 25°C)
It is to be understood that the process of the present invention is susceptible to modifications, changes and adaptations. Such variations / modifications and adaptation are intended to be within the spirit and scope of the present invention which is set forth by the following claims.


WE CLAIM:
1. A process for the preparation of ferrocene polyglycol oligomer (FPGO) comprising the steps of:
a) preparing diacetyl ferrocene by synthesising diacetyl ferrocene by reacting ferrocene, acetyl chloride 8B AICI3 preferably in the mole ratio of 1:2.6-2.8:2.4-3, respectively, by adding acetyl chloride drop wise at 20-30°C within 30-40 minutes, adding ferrocene to this solution under continuous stirring while maintaining the temperature to 20-30°C, pouring the said reactants over ice and purifying the crude obtained by recrystallisation in cyclohexane;
b) preparing bis (hydroxy ethyl) ferrocene from the said diacetyl ferrocene obtained from step (a) by reducing 0.1-0.2 M of diacetyl ferrocene completely to bis (hydroxy ethyl) ferrocene with 0.7-0.8 M sodium borohydride in 12-16 M isopropanol, at 70-90°C and recrystallising the product in n-heptane;
c) copolymerising the said bis (hydroxy ethyl) ferrocene and 1,4 butane diol by condensing the said bis (hydroxy ethyl) ferrocene and bis (hydroxy ethyl) ferrocene using boron trifluoride etherate to obtain ferrocene polyglycol oligomer (FPGO).

2. A process as claimed in claim 1 wherein bis hydroxy ethyl ferrocene is copolymerised with 1,4 butane diol by condensing 0.1-0.2 M of said bis hydroxy ethyl ferrocene with 0.5-0.6M of the 1,4 butane diol, under nitrogen, in presence of 0.003-0.005 M boron trifluoride etherate (in 10-15 cc of diethyl ether) at a temperature of 23-27 °C.
3. A process for the preparation of ferrocene polyglycol oligomer (FPGO) as herein described in example.

Documents:

1521-DEL-2003-Abstract-(18-05-2009).pdf

1521-DEL-2003-Abstract-26-05-2008.pdf

1521-del-2003-abstract.pdf

1521-DEL-2003-Claims-(18-05-2009).pdf

1521-DEL-2003-Claims-26-05-2008.pdf

1521-del-2003-claims.pdf

1521-del-2003-complete specification (granted).pdf

1521-DEL-2003-Correspondence-Others-26-05-2008.pdf

1521-del-2003-correspondence-others.pdf

1521-del-2003-correspondence-po.pdf

1521-DEL-2003-Description (Complete)-(18-05-2009).pdf

1521-del-2003-description (complete)-26-05-2008.pdf

1521-del-2003-description (complete).pdf

1521-del-2003-form-1.pdf

1521-del-2003-form-18.pdf

1521-del-2003-form-2.pdf

1521-DEL-2003-Form-3-26-05-2008.pdf

1521-DEL-2003-GPA-(18-05-2009).pdf

1521-DEL-2003-GPA-26-05-2008.pdf

1521-del-2003-gpa.pdf


Patent Number 235098
Indian Patent Application Number 1521/DEL/2003
PG Journal Number 31/2009
Publication Date 31-Jul-2009
Grant Date 24-Jun-2009
Date of Filing 08-Dec-2003
Name of Patentee THE DIRECTOR GENERAL
Applicant Address DEFENCE RESEARCH & DEVELOPMENT ORGANISATION MINISTRY OF DEFENCE, GOVT OF INDIA, DTE OF ER & IPR/IPR GROUP WEST BLOCK 8, WING 1, R K PURAM NEW DELHI-110011
Inventors:
# Inventor's Name Inventor's Address
1 GIRISH MUKUND GORE HEMRL, SUTARWADI, PUNE-411 021.
2 SHRI NANDAN ASTHANA HEMRL, SUTARWADI, PUNE-411 021.
3 KALPANA RAVINDRA TIPRE HEMRL, SUTARWADI, PUNE-411 021.
4 RASIK GHEWARCHAND BHATEWARA HEMRL, SUTARWADI, PUNE-411 021.
5 MOHANIRAJ ANANT TAPASWI HEMRL, SUTARWADI, PUNE-411 021.
6 CHANDRAKANT NANASAHEB DIVEKAR HEMRL, SUTARWADI, PUNE-411 021.
PCT International Classification Number C07F 17/02
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA