Title of Invention

"A PROCESS FOR THE PREPARATION OF AN INTERFACE COATING MATERIAL FOR CHEMICAL SENSORS"

Abstract A process for the preparation of an interface coating material for chemical sensors comprising of the steps of: synthesising the precursor chemical -4,4' - isopropylindenediphenol diallyl ether by refluxing 5-30 weight % of 4,4'- isopropylidenediphenol (bisphenolA), 10-60 weight % anhydrous K2CO3, 15-90 weight % allyl bromide and dry acetone taken 6 times in excess of bisphenol A, simultaneously stirring the reaction mixture @ 200-400 r.p.m. at 55-58°C for 16-24 hours, cooling to room temperature of 25°C, filtering and purifying the filtrate containing the precursor by rotary evaporator; the claisen rearranging of the precursor -4,4'- isopropylidenediphenol diallyl ether prepared in step (a) by refluxing 10-40% w/v preferably 15-20% w/v of the said 4,4'-isopropylidenediphenol diallyl ether dissolved in dry and distilled N,N-dimethylaniline at 190-194°C for 5-10 hours preferably 6-8 hours under an inert atmosphere of nitrogen, removing the solvent by distillation under reduced pressure leaving behind the coating material 2,2-Diallyl' 4-4' - isopropylidenediphenol, dissolving 5-30 mg/ml of 2,2'-Diallyl 4,4' - isopropylidenediphenol prepared in step (b) in a solvent like toluene, acetone, acetonitrile, benzene, chloroform, methanol etc. preferably methanol.
Full Text FIELD OF INVENTION
The present invention relates to a process for the preparation of a high performance interface coating material for chemical sensors. More particularly, the present invention relates to a process for preparation of 2,2'-diallyl-4,4' isopropylidene diphenol monomer which works as high performance coating material for the interface in chemical sensors.
PRIOR ART
Most of the modem chemical sensors employ a thin layer of a sorbent coating of a chemically selective material on an interface of the sensor transducer to collect and concentrate analyte(s) of interest. The sensor response is elicited by some change in the physicochemical properties of the coated material. The response (sensitivity and reversibility) of the sensor is largely dependent on the chemical nature and sorption-desorption behaviour of the interface coating material. The coated interface has to meet certain stringent properties. It should have rapid and high sorption of the analytes, as also their fast and complete desorption, chemical and thermal stability, and ease of preparation.
Vast number of commercially available hydrogen bond acidic functional group containing compounds, like docosanol, sorbitol, diglycerol and carboxylic acids, are of particular interest for use as chemical sensors in sensing of basic vapours of nerve agents and their simulants.
The main limitation of hydrogen bond acidic sensors is their tendency of self association which reduces the driving force for interacting with the basic vapours.
Another limitation is their volatile nature and limited stability.
On the basis of a survey of solubility interactions and hydroxylic organic functional groups, fluorinated alcohols, and fluorinated or fluoro-alkyl-substituted phenols have been used as target structural units in designing hydrogen-bond acidic sensitive polymers. Prominent amongst them are fluoro-polyol, hexafluoro-2-propanol (HFIP) containing polystyrene and polyisoprene, and hybrid organic-inorganic copolymers such as polysiloxanes containing diallyl hexafluorobisphenol-A. Interfaces coated with such materials are good chemical sensors and
exhibit fairly high sensitivity to nerve agents.
The disadvantage of these above known materials is. that their synthesis involves toxic gases such as hexafluoroacetone and HFIP.
Another drawback is the commercial non-availability of some of the precursor monomers thereby making the polymer synthesis tedious and a multi-step process.
Yet another disadvantage is the comparatively high cost of the precursors.
Still another drawback with these polymers is the difficulty in their purification.
Abraham et al (J. Chem. Soc. Perkin Trans 2, 1991, page 1417) have reported a number of involatile liquids based on 4,4'-isopropylidenediphenol (bisphenol) or other bisphenols as coatings for piezoelectric sorption detectors. Some of these liquids have been used in the synthesis of polymers such as fluorosiloxanes {Grate et al, Chem. Mater, 9, 1997, page 1201) and evaluated against a chemical simulant.
The main limitation of the above known process is that the polymers used are difficult to purify.
Other reported methods for the synthesis of 2,2'-Diallyl-4,4'-isopropylidenediphenol utilise solvents that are either hygroscopic [2-(2-ethoxyethoxy)ethanol] or air-sensitive (tetrahydronaphthalene).
The main limitation of the above processes is the comparative difficulty in removing the solvents due to their higher boiling points.
Another disadvantage is that the yield of the compound is low, upto -65%.
Some reported methods utilise a claisen rearrangement under high temperature without using any solvent.
The disadvantage of the above method is that it invariably leads to charring and requires stringent temperature control.
There was a need for a process for the preparation of a high
performance interface coating with a chemical sensor material with consistent and high physiosorption capacity for nerve agents. More importantly the need was for a high purity, an easily processable and soluble material which could be easily coated on a sensor interface.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide a process for the preparation of a high performance interface coating material for chemical sensors.
Other object of the present invention is to provide a process for the preparation of a high performance interface coating material for chemical sensors which is particularly sensitive to nerve agents and their simulants.
Another object of the present invention is to provide a process for the preparation of a high performance interface coating material for chemical sensors which exhibits fast dynamics and high magnitude of sorption-desorption of nerve agent vapours.
Yet another object of the present invention is to provide a process for the preparation of a high performance interface coating material which can be easily coated on a quartz or gold piezoelectric substrate.
Still another object of the present invention is to provide a process for the preparation of a high performance interface coating material for chemical sensors wherein the reaction time is highly reduced.
Further object of the present invention is to provide a process for the preparation of a high performance interface coating material for chemical sensors which is simple, rapid and convenient.
Yet further object of the present invention is to provide a process for the preparation of a high performance interface coating material for chemical sensors which uses cheaper, commercially available non-toxic chemicals.
Still further object of the present invention is to provide a process for the preparation of a high performance interface coating material which has hydrogen bond acidic nature coupled with chemical and thermal stability at least upto 80°C.
Another object of the present invention is to provide a process for the preparation of a high performance coating material which is highly pure and has quantitative yield.
Yet another object of the present invention is to provide a process for the preparation of a high performance interface coating material which is non-volatile and has a shelf life of at least one year.
DESCRIPTION OF INVENTION
According to this invention there is provided a process for the preparation of an interface
coating material for chemical sensors comprising of the steps of:
a) synthesising the precursor chemical -4,4'- isopropylidenediphenol diallyl ether by refluxing 5-30 weight % of 4,4'- isopropylidenediphenol (bisphenolA), 10-60 weight%, anhydrous K2CO3, 15-90 weight % allyl bromide and dry acetone taken in excess of bisphenol A while simultaneously stirring the reaction mixture @ 200-400 r.p.m. at 55-58°C for 16-24 hours, cooling to room temperature (about 25°C), filtering and purifying the filtrate containing the precursor by rotary evaporator;
b) the claisen rearranging of the precursor -4,4'- isopropylidenediphenol diallyl ether prepared in step (a) by refluxing 10-40% w/v preferably 15-20% w/v of the said 4,4'- isopropylidenediphenol diallyl ether dissolved in dry and distilled N,N-dimethylaniline at 190-194°C for 5-10 hours preferably 6-8 hours under an inert atmosphere of nitrogen, removing the solvent by distillation under reduced pressure leaving behind the coating material 2,2'-Diallyr4-4'-isopropylidenediphenol.
c) dissolving 5-30 mg/ml of 2,2'-Diallyl 4,4'- isopropylidenediphenol prepared in step (b) in a solvent like toluene, acetone, acetonitrile, benzene, chloroform, methanol etc. preferably methanol.
The process of the present invention is simple, rapid and with reduced number of steps thereby reducing the reaction time. A volatile solvent viz. Acetone is used which can be easily stripped off Another advantage of using acetone with anhydrous potassium carbonate is to circumvent the use of any phase transfer catalyst. Another solvent used is N,N-dimethylaniline, which is easily available and also easy to remove, it additionally provides a high yield (82%) of the compound. Moreover there is no need for stringent temperature control and there is no probability of charring.
A thin layer of 2,2'-Diallyl-4,4'- isopropylidenediphenol acts as an interface between the
analyte vapour (nerve agent) and the sensor transducer. The sensor response is in direct
proportion to be concentration of the analyte sorbed by the coating material.
DESCRIPTION OF THE PROCESS
According to the present invention, the process for the preparation of high performance
interface coating material for chemical sensors comprises of the following steps:
a) Synthesis of the precursor chemical -4,4'- isopropylidenediphenol diallyl
ether In a three-necked round bottomed flask fitted with a water condenser
and a pressure equalising dropping funnel, 5-30 weight% preferably 10-15 weight% of 4,4'-isopropylidenediphenol (bisphenolA), anhydrous K2CO3 (10-60 weight%, preferably 20-30 weight%,)and dry-acetone is taken 6 times in excess of bisphenol A. 15-90 weight% preferably 30-45 weight% allyl bromide is added dropwise over a period of 30 minutes, simultaneously stirring the reaction mixture @ 200-400 r.p.m. and refluxing at 55-58°C for 16-24 hours. A heavy white precipitate of KBr starts forming, soon after the refluxing. The completion of reaction is monitored by thin layer chromatography using silica gel as the stationary phase and petroleum ether (40°C to 80°C) as the mobile phase. The mixture is then cooled to room temperature (about 25°C) and filtered. The precursor is isolated from the filtrate and purified using rotary evaporator till a clear, viscous, tacky, oily liquid (boiling point 225°C at 0.02 mm Hg) is obtained.
b) The Claisen rearrangement of the precursor - 4,4'-
isopropylidenediphenol diallyl ether
10-40% (w/v), preferably 15-20% (w/v) of 4,4'-isopropylidenediphenol diallyl ether prepared in step a is dissolved in dry and distilled N,N-dimethylaniline and refluxed at 190-194°C for 5-10 hours (preferably 6-8 hours) under an inert atmosphere of nitrogen. The solvent is then removed by distillation under reduced pressure leaving behind the coating material 2,2'-Diallyl-4,4'-isopropylidenediphenol as a viscous liquid (boiling point 190°C at 0.5 mm Hg). The yield of the product is 80-88% with 100% purity.
c) Dissolving the coating material for preparing the interface
The solution used for preparing the interface is made by dissolving 5-30 mg/ml preferably 8-12 mg/ml of 2,2'-Diallyl 4,4'isopropylidenediphenol prepared in step b in a solvent like toluene, acetone, acetonitrile, benzene, chloroform, methanol etc, preferably methanol.
2-10 µl preferably 3-6µl of this solution is coated on the piezoelectric crystal substrate by dipping, spraying, spinning, layering by a dropper or a microlitre syringe, preferably a microlitre syringe. The coated crystal is then dried at about 80°C under a vacuum of 0.5 mm Hg.
This invention will now be illustrated with a working example, which is intended to be typical example to explain the technique of the
present invention and is not intended to be taken restrictively to imply any limitation to the scope of the present invention.
Working Example
For the synthesis of 4,4'-isopropyhdenediphenol diallyl ether, 0.05 mol (11.4g) of 4,4'-isopropylidenediphenol (bisphenolA) and 0.15 mol (36g) of allyl bromide were refluxed in 100 ml of dry acetone in the presence of 0.1 mol (27.6g) of anhydrous K2CO3 at 55-58°C for 20 hours with continuous stirring at about 300 r.p.m. The reaction was monitored by thin layer chromatography. The mixture was then cooled to room temperature and filtered. The filtrate was subjected to rotary evaporation to give 95% yield of 4,4'-isopropylidenediphenol diallyl ether. 0.03 mole (lOg) of 4,4'-isopropylidenediphenol diallyl ether was dissolved in 50 ml of N,N-dimethylaniline and was refluxed at 190-194°C for 8 hours under an inert atmosphere of nitrogen. The solvent was removed by distillation under reduced pressure and the product 2,2'-Diallyl-4,4'-isopropylidenediphenol was collected as viscous liquid (yield 82%, purity 100%). lOmg of this compound was dissolved in 10 ml of methanol, approximately 5µl of this solution was dropped on the piezoelectric crystal substrate using a microlitre syringe. The coated crystal was then dried at 80°C under a vacuum of 0.5 mm Hg.
Evaluation of the interface coated with the coating material of the present invention:
The average value for shift in frequency (AF) of the coated crystal was 5KHz. The crystal coated with 2,2'-Diallyl-4,4'-isopropylidenediphenol of the present invention was exposed to pre-defined concentration of sarin (90 mg/m'^) and the sensor (10 MHz bulk acoustic wave device) response (AF) values were noted. The value was of the order of 110 Hz for 1 min exposure and 320 Hz for 5 min exposure. The response time (time for attaining 90% sorption) of the sensor was 90 sec and desorption was complete within 100 sec. The coated material was subjected to repeated exposures of sarin and the performance was found to be consistent.
A similar methodology was followed on the surface acoustic wave (SAW) sensor of 430 MHz oscillating frequency. The crystal was spin-coated with 2,2'-Diallyl 4,4'isopropylidenediphenol and exposed to the vapours of dimethyl methylphosphonate (DMMP). AF values obtained were significantly high (12500 Hz) indicating a high affinity of the compound for the sensing of DMMP.
It is understood that the process of the present invention is susceptible to modifications, changes, adaptations by those skilled in the art. Such modifications, changes adaptations are intended to be within the scope of the present invention which is further set forth under the following claims:








I CLAIM
1. A process for the preparation of an interface coating material for
chemical sensors comprising of the steps of:
(a) synthesising the precursor chemical -4,4' - isopropylindenediphenol diallyl ether by refluxing 5-30 weight % of 4,4'- isopropylidenediphenol (bisphenolA), 10-60 weight % anhydrous K2CO3, 15-90 weight % allyl bromide and dry acetone taken 6 times in excess of bisphenol A, simultaneously stirring the reaction mixture @ 200-400 r.p.m. at 55-58°C for 16-24 hours, cooling to room temperature of 25°C, filtering and purifying the filtrate containing the precursor by rotary evaporator;
(b) the claisen rearranging of the precursor -4,4'- isopropylidenediphenol diallyl ether prepared in step (a) by refluxing 10-40% w/v preferably 15-20% w/v of the said 4,4'-isopropylidenediphenol diallyl ether dissolved in dry and distilled N,N-dimethylaniline at 190-194°C for 5-10 hours preferably 6-8 hours under an inert atmosphere of nitrogen, removing the solvent by distillation under reduced pressure leaving behind the coating material 2,2-Diallyl' 4-4' - isopropylidenediphenol,
(c) dissolving 5-30 mg/ml of 2,2'-Diallyl 4,4' - isopropylidenediphenol prepared in step (b) in a solvent like toluene, acetone, acetonitrile, benzene, chloroform, methanol etc. preferably methanol.
2. A process as claimed in claim 1, wherein step (a), 4,4-
isopropylidenediphenol is present preferably in an amount of 10-15
wt%, anhydrous K2CO3 preferably in an amount of 20-30wt%, allyl
bromide preferably in an amount of 30-45 wt%.
3. A process as claimed in claim 1 wherein 8-12 mg/ml of the precursor of step (b) is dissolved in said solvent.

Documents:

265-del-2004-Abstract-(31-08-2012).pdf

265-del-2004-abstract.pdf

265-del-2004-Claims-(31-08-2012).pdf

265-del-2004-claims.pdf

265-DEL-2004-Correspondence Others-(31-08-2012).pdf

265-DEL-2004-Correspondence-Others-(23-12-2009).pdf

265-del-2004-correspondence-others.pdf

265-DEL-2004-Correspondence-PO-(23-12-2009).pdf

265-del-2004-correspondence-po.pdf

265-del-2004-description (complete).pdf

265-del-2004-form-1.pdf

265-del-2004-Form-18 (18-10-2011).pdf

265-del-2004-form-2.pdf

265-del-2004-Form-3-(31-08-2012).pdf

265-del-2004-GPA-(31-08-2012).pdf


Patent Number 255035
Indian Patent Application Number 265/DEL/2004
PG Journal Number 03/2013
Publication Date 18-Jan-2013
Grant Date 16-Jan-2013
Date of Filing 23-Feb-2004
Name of Patentee THE DIRECTOR GENERAL,DEFENCE RESEARCH & DEVELOPMENT ORGANIZATION
Applicant Address DEFENCE RESEARCH & DEVELOPMENT ORGANISATION MINISTRY OF DEFENCE, GOVT OF INDIA, WEST BLOCK-VIII, WING-I, SECTOR-1, RK PURAM, NEW DELHI-110 066, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 PRANAV KUMAR GUTCH DEFENCE RESEARCH & DEVELOPMENT ESTABLISHMENT JHANSI ROAD GWALIOR-474 002, INDIA.
2 VINITA DUBEY DEFENCE RESEARCH & DEVELOPMENT ESTABLISHMENT JHANSI ROAD GWALIOR-474 002, INDIA.
3 GOVERDHAN LAL DEFENCE RESEARCH & DEVELOPMENT ESTABLISHMENT JHANSI ROAD GWALIOR-474 002, INDIA.
4 DEVENDRA KUMAR JAISWAL DEFENCE RESEARCH & DEVELOPMENT ESTABLISHMENT JHANSI ROAD GWALIOR-474 002, INDIA.
5 KRISHNAMURTHY SEKHAR DEFENCE RESEARCH & DEVELOPMENT ESTABLISHMENT JHANSI ROAD GWALIOR-474 002, INDIA.
PCT International Classification Number G01N 33/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA