FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
PROVISIONAL / COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION :
A process of preparing 1,4-bis (2 methyl styryl) benzene and 1,4- bis (2 methyl styryl) benzene obtained therefrom.
2. APPLICANT
(a) NAME : SUDARSHAN CHEMICAL INDUSTRIES LTD.
(b) NATIONALITY : An Indian Company registered under the provisions of
the Companies Act, 1956.
(c) ADDRESS : 162, Wellesley Road,
PUNE- 411001, Maharashtra State, India.
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL COMPLETE
The following specification described the The following specification
invention. particularly describes the invention and
the manner in which it is to be
performed.
4. DESCRIPTION (Description starts from page 2)
5. CLAIMS: Given on a separate sheet
6. DATE AND SIGNATURE: Given at the end of last page of specification.
7. ABSTRACT OF THE INVENTION: Given on a separate sheet

TECHNICAL FIELD:
The present invention relates to a process for the preparation of 1,4-bis (2 methyl styryl) benzene (BIS MSB)suitable for scintillation application. More particularly, the present invention relates to a process for the preparation of 1,4-bis(2-methyl styryl) benzene by reacting 2-methyl benzyl triphenylphosphonium halides with terephaldicarboxadehyde in presence of a suitable base.
The expression BIS MSB used in the specification means the compound of the present invention.
The main object of the present invention is to provide a novel process for the preparation of 1,4- bis (2-methyl styryl) benzene.
Another object of the present invention is to make 1,4-bis (2-methyl styryl) benzene using less expensive, easily accessible starting materials.
Still further object of the present invention is to make scintillation grade 1,4 bis (2 methyl styryl) with high yield and purity.
BACKGROUND AND PRIOR ART:
1,4-bis (2- methyl styryl) benzene (Bis MSB) is a valuable compound used for scintillation application. In the study of fluorescent compounds, Pichal et al suggested the use of distyryl benzene as a scintillation solute in plastic scintillators. This was followed by Adam Heller studies of the scintillation properties of substituted distyrylbenzenes (Compare Journal of Chemical Physics, 50, 26,1953; French patent 1071794(1954); Journal of Chemical Physics, 40(10), 2839, 1964.
Bis styrylbenzene derivatives have been prepare by several known methods. One such known method is described in Journal of Organic Chemistry, 24, 1246(1959) that involves Wittig reaction of p-xylene- bis-triphenyl phosphonium chloride and substituted
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aromatic aldehydes in presence of lithium ethoxide in alcohol. Under this condition mixture of three geometrical isomers separate out which needs to be heated in hydrocarbon solvent to convert into desired trans-isomer of distyryl benzene derivatives.
Another general method for substituted distyrylbenzene disclosed by Drefahl et al. in Ber.94,907 (1961), wherein, Grignard reaction of 4-stilbenzaldehydes and benzyl magnesium chlorides is conducted followed by dehydration of resulting diol to obtain desired product with very low overall yield.
Further an effort was made to improve the yields obtained by Grignard reaction between substituted benzyl magnesium chlorides and terephthaadehyde. Adam Heller, Journal of Chemical Physics, 40, 2839, 1964 reported that although various solvents and organometallic compounds were tried at varied range of temperature conditions, the yields always remained below 20%
R.E. Buckles et al, Organic Synthesis, 33,70 (1953); Organic synthesis,33,88 (1953) have disclosed process for preparation distyryl benzenes that involves condensation of p- phenylenediacetic acid with aromatic aldehydes under the conditions of either the Perkin reaction or those Dobbner -Miller reaction followed by decarboxylation of the product thus, obtained yielded the expected respective products in low yield.
Preparations of symmetrical distyryl derivatives are described by Arient, Josef, Collect. Czech . Chemical Communications, 46(1), 101-6 (1981) wherein 1,4- distyryl derivatives were prepared by condensation of 1,4- bisdiethyl benzyl phosphonate and appropriately substituted aromatic aldehyde in presence of potassium ethoxide in DMF according to Wittig - Horner reaction.
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Deficiencies Of Prior Art:
1. The prior art processes either utilize relatively expensive starting materials or provide low yields due to the formation of undesired side products.
2. The process for preparation of Bis styryl derivatives involves rigorous purification steps.
Description of the Present Invention:
Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.
The present invention relates to a process for the prepararion of pure 1,4- Bis(2-methyl styryl)benzene (Bis MSB) of formula (I) in relatively high yields and purity. More particularly, the present invention relates to a process for the preparation of pure high quality 1,4 -Bis(2- methyl styryl)(Bis MSB) suitable for scintillation application. The present invention also discloses a process for the preparation of 1,4- Bis(2- methyl styryl) benzene of formula(I) by reacting 2-methyl benzyl triphenyl phosphonium halides of formula (III) where halides X is CI, Br or I with terephaldicarboxaldehyde of formula (II) in presence of suitable base like sodium ethoxide, potassium tert.butoxide, sodium tert.butoxide, lithium ethoxide, potassium ethoxide, sodium methoxide and suitable polar solvent like methanol, toluene, xylene, dimethyl formamide, dimethyl sulfoxide, ethanol atl0degC-180degC.
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Example:
In a four- necked round-bottomed flask equipped with overhead stirrer,thermo well, reflux condenser, nitrogen purger and guard tube were placed 2-methyl benzyltriphenylphosphonium halide (CI, Br or I) (0.22- 0.33 mole) with base (0.24 to 0.33 mole) diluted with 1ml to 5ml solvent per 1 milimole of phosphonium halide and stirred reaction mixture at room temperature for 0-12 hours. In to the reaction mixture, terephthaldicaboxaldehyde (0.11 moles) was added and reaction temperature raised to 35-180 deg C. The reaction was maintained at 35-180 deg C for about 10-55 hours. The progress of the reaction was monitored by thin layer chromatography (TLC). After completion, reaction mixture was cooled to 20-30 deg C, filtered through suction and dried under vacuum at 30-80 deg C till constant weight. The crude product weighed 16.2 - 19.4 g, having melting point 179-181 deg C which was analysed by High pressure liquid chromatography (HPLC) for its purity. The resultant 1,4-Bis(2-methylstyryl) benzene could be recrystallizes by dissolving 1 gm of crude product in 15 ml toluene at 80 deg C.
Variations:
1. Various bases which can be used are sodium ethoxide, potassium tert butoxide, sodium tert butoxide, lithium ethoxide, potassium ethoxide and sodium methoxide.
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2. Various solvents which can be used are methanol, xylene, toluene, ethanol, dimethylformamide and dimethyl sulfoxide.
The embodiments of the invention as described above and the method disclosed of the present invention will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention which is defined by the scope of the following claims.
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We Claim:
1. A novel process of preparing 1,4- bis (2methyl styryl) benzene of formula (I) as shown below comprising reacting 2 methyl benzyl triphenyl phosphoriium halides of formula (III) as shown below wherein X is CI, Br or I with terephaldicarboxaldehyde of formula (II) in the presence of suitable base such as herein described and solvent such as herein described at 10 deg C to 180 deg C

2. A process of preparing l,4-bis(2 methyl styryl) benzene of formula (I) as claimed in claim 1, wherein the solvent is selected from the group comprising of methanol, xylene, toluene, ethanol, dimethylformamide, dimethyl sulfoxide.
3. A process as claimed in claim 1, wherein the base is selected from the group comprising of sodium ethoxide, potassium tert.butoxide, sodium tert.butoxide, lithium ethoxide, potassium ethoxide, sodium methoxide.
4. A process as claimed in claim 1, wherein 2 methyl benzyl triphenyl phosphonium
halides of formula (III) is used in 2.0 to 3.0 mole equivalent.
5. A process as claimed in claim 1, wherein base is used in 2.2 to 3.0 mole equivalent.
6. A process as claimed in claim 1, wherein reaction performed is at atmospheric
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pressure.
7. A process of as claimed in claim 1 substantially as herein described with reference to the example.
8. 1,4- bis (2 methyl styryl) benzene prepared by the process as claimed in claims 1 to 7 above.


Dated this 18th September, 2006

Abstract
This invention relates to a process of preparing 1,4- bis (2methyl styryl ) benzene of formula (I) as shown below comprising reacting 2 methyl benzyl triphenyl phosphonium halides of formula (III) as shown below wherein X is CI, Br or I with terephaldicarboxaldehyde of formula (II) in the presence of suitable base and solvent at lOdegCto 180degC

In the above process the various bases which can be used are sodium ethoxide, potassium
tert.butoxide, sodium tert.butoxide, lithium ethoxide, potassium ethoxide and sodium
methoxide.
In the above process the various solvents which can be used are methanol, xylene,
toluene, ethanol, dimethylformamide and dimethyl sulfoxide.