FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10 and Rule 13)
1. Title of the Inventioo:-
Improved Amine Based Additive Composition for Control and Inhibition of Polymerization of Aromatic Vinyl Monomers, and Method of Use thereof.
2. Applicant(s):-
(a) Name : DORF KETAL CHEMICALS (INDIA) Private Limited
(b) Nationality : An Indian Company
(c) Address : Dorf Ketal Tower, D'Monte Street, Orlem, Malad (W),
MUMBAI -400,064, Maharashtra, INDIA
3. Preamble to the Description:-
PROVISIONAL SPECIFICATION:
The following specification describes the Invention

Title of the invention:
Improved Amine Based Additive Composition for Control and Inhibition of Polymerization of Aromatic Vinyl Monomers, and Method of Use thereof.
Field of the invention:
The present invention relates to an improved amine based additive composition for control and inhibition of polymerization of aromatic vinyl monomers, wherein aromatic vinyl monomer, for example is styrene, wherein improvement comprises a composition of one or more aliphatic amines with mixture of one or more of aromatic compounds and one or more nitroxide (or nitroxyl) compounds.
In one embodiment, the present invention relates to use of improved amine based additive composition of present invention to control and inhibit polymerization of aromatic vinyl monomers, particularly of styrene, wherein improvement comprises use of a composition comprising one or more aliphatic amines with mixture of one or more of aromatic compounds and one or more nitroxide (or nitroxyl) compounds.
In another embodiment, the present invention relates to method of preparation of improved additive composition of present invention for control and inhibition of polymerization of aromatic vinyl monomers, particularly of styrene, wherein improvement comprises preparation of composition comprising one or more aliphatic amines with mixture of one or more of aromatic compounds and one or more nitroxide (or nitroxyl) compounds.
In still another embodiment, the present invention relates to method of controlling and inhibiting polyniejization. of .aromatic vinyl monomers, particularly of styrene by employing improved additive composition of present invention, wherein improvement comprises treating the stream containing aromatic vinyl monomers with a composition comprising one or more aliphatic amines with mixture of one or more of aromatic compounds and one or more nitroxide (or nitroxyl) compounds.
Background of the invention:
The polymerization of aromatic vinyl monomers, particularly of styrene during processing is a matter of concern, because it causes formation of unwanted polymers and results in loss of yield of end product and makes the process un-economical.
In the art use of inhibitors and retarders, and combination thereof to overcome problem of polymerization of styrene has been reported.

The problem of using the inhibitors alone is that these are to be added continuously or at regular interval, because once they are consumed, the polymerization will re-start.
The problem of using the retarders alone is that these are not very effective to reduce polymerization of styrene to a level of substantial inhibition or to the acceptable level of inhibition.
The prior art proposes quinone methide based composition comprising quinone methide and 4HT (4 hydroxy tempo 2,2,6,6-tetramethyl-,l-oxide) as styrene polymerization inhibitor. However, the inventor has found [refer to examples and corresponding data] that main problem of using this known composition of quinone methide (QM) and 4HT is that even with higher amounts of the composition, the problem of polymerization is not resolved to acceptable level.
Therefore, the industry is aiming for additive composition wherein the amount of aromatic and nitroxide compounds can be reduced or minimized so that the resulted composition is economical as well as safe for human being.
Any effort to reduce or minimize consumption of aromatic compounds and/or nitroxide compounds will lessen the problems of the industry.
Need of the Invention:
Therefore, there is still .a need, pf an. effective additive composition and method of its use and preparation, and method of controlling and inhibiting polymerization of vinyl aromatic monomers by employing said composition, wherein the additive composition is not only suitable for substantial control and inhibition of polymerization of aromatic vinyl monomers, particularly styrene, but also comprises substantially reduced or minimized amounts of aromatic and nitroxide compounds.
Problem to be solved by the Invention:
Therefore, the present invention aims at providing a solution to above-described existing industrial problems by providing effective additive composition and method of its use and preparation, and method of controlling and inhibiting polymerization of vinyl aromatic monomers, wherein the additive composition is not only suitable for substantial control and inhibition of polymerization of aromatic vinyl monomers, particularly styrene, but also comprises substantially reduced or minimized amounts of aromatic and nitroxide compounds.

Objects of the Invention:
Accordingly, the main object of present invention is to provide an effective and improved amine based additive composition and method of its use and preparation, and method of controlling and inhibiting polymerization of vinyl aromatic monomers, wherein the additive composition is not only suitable for substantial control and inhibition of polymerization of aromatic vinyl monomers, particularly styrene, but also comprises substantially reduced or minimized amounts of aromatic and nitroxide compounds.
Another main object of present invention is to provide an effective and improved amine based additive composition and method of its use and preparation, and method of controlling and inhibiting polymerization of vinyl aromatic monomers, wherein the additive composition comprises substantially reduced or minimized amount of aromatic and nitroxide compounds, and is still suitable for substantial control and inhibition of polymerization of aromatic vinyl monomers, particularly styrene, and is still required in relatively lower dosage as compared to dosage of combination of aromatic and. nitroxide .compounds.for achieving the same or better acceptable level of control and inhibition of polymerization of styrene.
This is also an object of present invention to provide an effective and improved amine based additive composition and method of its use and preparation, and method of controlling and inhibiting polymerization of vinyl aromatic monomers, wherein the additive composition comprises amine, and reduced or minimized amount of aromatic and nitroxide compounds, and is still suitable for substantial control and inhibition of polymerization of aromatic vinyl monomers, particularly styrene, and is still required in relatively lower dosage as compared to dosage of combination of aromatic and nitroxides compounds for achieving the same or better acceptable level of control and inhibition of polymerization of styrene, and wherein the amine is one or more aliphatic amines.
The present invention particularly aims at providing an effective and improved amine based additive composition and method of its use and preparation, and method of controlling and inhibiting polymerization of vinyl aromatic monomers, wherein the additive composition comprises amine, and reduced or minimized amounts of aromatic compounds including quinone methide (QM) and nitroxides (i.e. nitroxyl) compounds including l-oxyN2,2,6,6, tetrarnemylpiepridin-4-ol (or 4 Hydroxy Tempo or 4HT) and

is still suitable for substantial control and inhibition of polymerization of aromatic vinyl monomers, particularly styrene, and is still required in relatively lower dosage as compared to dosage of combination of aromatic and nitroxides compounds for achieving the same or better acceptable level of control and inhibition of polymerization of styrene, and wherein the amine is one or more of aliphatic amines, and therefore, the composition of present invention is not only economical, but is also environment friendly.
The present invention also aims at improving the performance of a) additives consisting of aromatic compounds and b) additives consisting of nitroxides (or nitroxyl) compounds, in-addition to c) additive compositions consisting of combination of aromatic compounds and nitroxide compounds, wherein the present composition comprises one or more aromatic compounds and one or more nitroxide compounds, and further comprises one or more aliphatic amines.
The present invention also aims at improving the performance of a) additives consisting of aromatic compounds, and b) additives consisting of nitroxides (or nitroxyl) compounds, in-addition to c) additive compositions consisting of combination of aromatic compounds and nitroxide compounds at a wider range of temperature including the higher temperature, wherein the composition comprises one or more aromatic compounds and one or more nitroxide compounds, and further comprises one or more aliphatic amines.
The present invention also aims at improving the performance of a) additives consisting of aromatic compounds, and b) additives consisting of nitroxides (or nitroxyl) compounds, in-addition to c) additive compositions consisting of combination of aromatic compounds and nitroxide compounds at a wider range of temperature including the higher temperature and in presence of air, wherein the composition comprises one or more aromatic compounds and one or more nitroxide compounds, and further comprises one or more aliphatic amines.
Other objects and advantages of present invention will become more apparent from the following description when read in conjunction with examples, which are not intended to limit scope of present invention.
Description and Preferred Embodiments of the Invention:
With aim to overcome above-described problems of prior art and to achieve above-described objects of the present invention, the inventor has found that when an

aliphatic amine is added to composition consisting of aromatic and nitroxide compounds, then not only polymerization controlling and inhibiting efficiency of composition consisting of aromatic and nitroxide compounds is substantially improved, but polymerization of aromatic vinyl monomers, particularly of styrene, surprisingly and unexpectedly, is also controlled and inhibited to the acceptable level with substantially reduced and minimized dosage of aromatic and nitroxide compounds in a composition comprising one or more aliphatic amines, and one or more aromatic compounds and one or more nitorxide compounds, which makes the present composition economical as well as environment friendly.
With aim to overcome above-described problems of prior art and to achieve above-described objects of the present invention, the inventor has found that when an aliphatic tertiary amine, or aliphatic tertiary amine containing one or more hydroxyl groups is added to composition consisting of aromatic and nitroxide compounds, then not only polymerization controlling and inhibiting efficiency of composition consisting of aromatic and nitroxide compounds is substantially improved, but polymerization of aromatic vinyl monomers, particularly of styrene, surprisingly and unexpectedly, is also controlled and inhibited to the acceptable level with substantially reduced and minimized dosage of aromatic and nitroxide compounds in a composition comprising one or more aromatic compounds and one or more nitorxide compounds, and further comprising one or more of aliphatic tertiary amines or aliphatic tertiary amines containing one or more hydroxyl groups, which makes the present composition economical as well as environment friendly.
Accordingly, the present invention relates to improved amine additive composition for control and inhibition of polymerization of aromatic vinyl monomers, particularly of styrene comprising one or more aromatic compounds and one or more nitorxide compounds, and further comprising one or more of aliphatic amines.
In accordance with present invention, the aliphatic amine is an aliphatic tertiary amine.
In accordance with present invention, the aliphatic tertiary amine is aliphatic tertiary amine containing one or more hydroxyl groups in the alkyl chain of the tertiary amine.
In accordance with present invention, the aliphatic tertiary amine contains three hydroxyl groups in the alkyl chain of the tertiary amine.

In accordance with present invention, in the aliphatic tertiary amine containing one or more hydroxyl groups, the hydroxyl groups are hydroxyalkyl groups.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may be linear, branched or cyclic.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may contain one or more hydroxy alkyl groups.
In accordance with preferred embodiment of the present invention, the aliphatic tertiary amine containing three hydroxyl groups is tri-isopropanol amine [TIPA].
The inventor has been found that when composition of present invention comprises one or more aliphatic amines, the efficiency of aromatic and nitroxide compounds to control and inhibit polymerization of aromatic vinyl monomers, particularly of styrene is, surprisingly and unexpectedly, substantially improved to the acceptable level that's too at substantially reduced or minimized dosages of aromatic and nitroxide compounds, thereby making the composition of present invention relatively more economical and environment friendly.
In accordance with one of the preferred embodiments of the present invention, the composition of present invention is added to the stream containing aromatic vinyl monomers, particularly styrene in an amount varying from about 0.01 ppm to about 2000 ppm by weight of me-.stream^grvhydrpcarbon stream).
In accordance with present invention, the aromatic compound is preferably quinone methide (QM).
Accordingly, in another embodiment, the present invention also relates to method of using improved amine based additive composition of present invention described herein, a reference to which is drawn in entirety, to control and inhibit polymerization of aromatic vinyl monomers, particularly of styrene, wherein the stream comprising aromatic vinyl monomer, particularly styrene is treated with an additive composition comprising one or more aromatic compounds and one or more nitorxide compounds, and further comprising one or more of aliphatic amines.
In accordance with present invention, the aliphatic amine is an aliphatic tertiary amine.
In accordance with present invention, the aliphatic tertiary amine is aliphatic tertiary amine containing one or more hydroxyl groups in the alkyl chain of the tertiary amine.

In accordance with present invention, the aliphatic tertiary amine contains three hydroxy 1 groups in the alkyl chain of the tertiary amine.
In accordance with present invention, in the aliphatic tertiary amine containing one or more hydroxyl groups, the hydroxyl groups are hydroxyalkyl groups.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may be linear, branched or cyclic.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may contain one or more hydroxy alkyl groups.
In accordance with preferred embodiment of the present invention, the aliphatic tertiary amine containing three hydroxyl groups is tri-isopropanol amine [TIPA].
In accordance with one of the preferred embodiments of the present invention, the method comprises adding an amount varying from about 0.01 ppm to about 2000 ppm of present composition by weight of the stream (or hydrocarbon stream) containing aromatic vinyl monomers, particularly styrene.
Accordingly, in still another embodiment, the present invention also relates to method of controlling and inhibiting polymerization of aromatic vinyl monomers, particularly of styrene by employing amine based additive composition of present invention described herein, a reference to which is drawn in entirety, wherein the stream comprising aromatic vinyl monomers, particularly styrene is treated with an additive composition comprising one or more aromatic compounds and one or more nitorxide compounds, and further comprising one or more of aliphatic amines.
In accordance with present invention, the aliphatic amine is an aliphatic tertiary amine.
In accordance with present invention, the aliphatic tertiary amine is aliphatic tertiary amine containing one or more hydroxyl groups in the alkyl chain of the tertiary amine.
In accordance with present invention the aliphatic tertiary amine contains three hydroxyl groups in the alkyl chain of the tertiary amine.
In accordance with present invention, in the aliphatic tertiary amine containing one or more hydroxyl groups, the hydroxyl groups are hydroxyalkyl groups.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may be linear, branched or cyclic.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may contain one or more hydroxy alkyl groups.

In accordance with preferred embodiment of the present invention, the aliphatic tertiary amine containing three hydroxy! groups is tri-isopropanol amine [TIPA].
In accordance with one of the preferred embodiments of the present invention, the method comprises adding an amount varying from about 0.01 ppm to about 2000 ppm of present composition by weight of the stream (or hydrocarbon stream) containing aromatic vinyl monomers, particularly styrene.
In accordance with one of the embodiments of the present invention, the composition of present invention may be mixed with stream containing aromatic vinyl monomers either before the stream enters into processing system or after the stream has entered into processing system, but preferably the composition is added to the stream containing aromatic vinyl monomers before its processing starts so that polymerization of aromatic vinyl monomers is avoided or minimized.
In accordance with one of the embodiments of the present invention, the present composition can be used over a wide range of temperature including 50 degree C to 155 degree C, preferably over the range of 90 degree C to 120 degree C.
The composition of present invention may be prepared in any known manner to prepare the compositions.
Accordingly, in still another embodiment, the present invention also relates to method of preparing amine based additive composition of present invention described herein, a reference to which is drawn in entirety, for controlling and inhibiting polymerization of aromatic vinyl monomers, particularly of styrene, wherein one or more aromatic compounds, one or more nitroxide compounds and one or more aliphatic amine compounds are added individually or after mixing to the stream.
In accordance with present ,inventipn,sthe,aliphatic amine is an aliphatic tertiary amine.
In accordance with present invention, the aliphatic tertiary amine is aliphatic tertiary amine containing one or more hydroxyl groups in the alkyl chain of the tertiary amine.
In accordance with present invention, the aliphatic tertiary amine contains three hydroxyl groups in the alkyl chain of the tertiary amine.
In accordance with present invention, in the aliphatic tertiary amine containing one or more hydroxyl groups, the hydroxyl groups are hydroxyalkyl groups.
In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may be linear, branched or cyclic.

In accordance with present invention, the hydrocarbon in the aliphatic tertiary amine may contain one or more hydroxy alkyl groups.
In accordance with preferred embodiment of the present invention, the aliphatic tertiary amine containing three hydroxyl groups is tri-isopropanol amine [TIPA].
The present invention is now described with the help of following examples, which are not intended to limit scope of the present invention, but have been incorporated to illustrate mode and best mode of performing the present invention.
Experiments:
Main Experiment:
In the following experiments, weighed amount of distilled styrene (or hydrocarbon stream in gms) and weighed amount of additives (in ppm by weight of styrene or hydrocarbon stream) were taken in a tube reactor equipped with thermometer and nitrogen inlet and outlet. In these experiments, enough N2 flow was maintained to ensure proper agitation. The reactions were carried out at 120°C under continuous nitrogen flow for 2 hours. After the selected duration, the reactor was cooled to below 10°C by immersing in crushed ice. The contents of the reactor were then poured in a beaker. To this same beaker, approximately for 1.5-2g chilled polymerization mixture, about 80g methanol was used to precipitate the polymer formed in the styrene solution. The precipitate obtained was filtered, dried to remove methanol, and weighed. The weight of the precipitate formed is reported as % polymer formed.
It may be noted that styrene was purified before use to remove the stabilizers.
In following examples, the prior additive is a composition consisting of aromatic compound and nitroxide compound, wherein aromatic compound is Quinine Methide (QM); and nitroxide compound is 1 oxyl-2,2,6,6, tetramethylpiepridin-4-ol (or 4 Hydroxy Tempo or 4-HT), which are taken in an amount of about 100, 150, 200, 300, or 400 ppm in various weight ratios of 90:10 [referred as QM:4HT (90:10)], 80:20 [referred as QM:4HT (80:20)], 50:50 [referred as QM:4HT (50:50)], 30:70 [referred as QM:4HT (30:70)] of QM and 4-HT.
In following examples, the present additive composition is a composition comprising Quinine Methide (QM) being aromatic compound and 1-oxyl-2,2,6,6, tetramethylpiepridin-4-ol (or 4 Hydroxy Tempo or 4-HT) being nitroxide compound, and further comprising tri-isopropanol amine (TIPA) being aliphatic tertiary amine

containing three hydroxyl groups, wherein about 1 ppm of TIPA is added to 100 ppm and about 2 ppm of TIPA is added to 200 ppm of above-said mixture of nitroxide and aromatic compounds taken in above-said weight ratios of 90:10, 80:20, 50:50, and 30:70 of QM and 4-HT.
Experiments:-
The results of above Main Experiment when performed with lOg of distilled styrene by heating to 120°C for 2h are provided in Table-I, Table-II and Table-Ill.
Table-I

Weight Ratio of
QMand4HT
in QM and 4HT
mix. of Prior Art
and Present
Additives % Polymer formed with Prior
Art Additive
(100 ppm of QM
and 4HT mix.) % Polymer formed
with Present
Additive
(lOOppmofQM
and 4HT mix., and
1 ppm of TIPA Technical Effects of present composition
90/10 3.13 1.30 Polymerization inhibition efficiency of composition consisting of aromatic and nitroxide compounds (QM and 4HT) is substantially improved, and % polymer formed is
80/20 3.05 1.25

50/50 4.95 0.98 substantially reduced on just on addition of 1 or 2 ppm of aliphatic tertiary amine in composition consisting of aromatic and nitroxide compounds (QM and 4HT).
30/70 3.18 1.21

Table-II

Weight Ratio of % Polymer formed with Prior % Polymer formed
QM and 4HT
with Present
in QM and 4HT Additive Technical Effects of present
mix. of Prior Art and Present (200 ppm of QM (200 ppm of QM and 4HT mix., and composition
and 4HT mix.)
Additives 2 ppm of TIPA
Polymerization inhibition efficiency
90/10 1.64 0.23 of composition consisting of aromatic and nitroxide compounds

80/20 1.56 0.22 (QM and 4HT) is substantially improved, and % polymer formed is
substantially reduced on just on
50/50 1.93 0.11 addition of 1 or 2 ppm of aliphatic tertiary amine in composition

30/70 1.48 0.21 consisting of aromatic and nitroxide
compounds (QM and 4HT).

The reasons for sudden increase in % polymer formed for prior art additive composition consisting of QM and 4-HT in weight ratio of 50:50, and for present additive composition comprising QM and 4-HT in weight ratio of 30:70 with TIPA are not known presently. However, it is understood from above Table-I and Table II that when just 1 ppm or 2 ppm of TIPA is added respectively to 100 ppm or 200 ppm of mixture of QM and 4-HT in various weight ratios (prior art additive), the efficiency of prior art additive to control and inhibit polymerization of styrene is, surprisingly and unexpectedly, improved substantially.
It can also be observed from Table-I and Table-II that polymerization of styrene is, surprisingly and unexpectedly, substantially reduced just on addition of 1 ppm or 2 ppm of TIPA respectively in 100 ppm or 200 ppm of the mixture of QM and 4-HT in various weight ratios (prior art additive).
Table-Ill

Weight Ratio of
QM and 4HT
inQMand4HT
mix. of Prior Art
Additive % Polymer formed
with Prior Art
Additive
(150 ppm of QM
and 4HT mix.) % Polymer formed
with Prior Art
Additive
(300 ppm of QM and
4HT mix.) % Polymer formed with
Prior Art Additive
(400 ppm of QM and
4HT mix.)
90/10 2.17 0.58 0.24
80/20 2.15 0.55 0.22
50/50 3.13 0.54 0.27
30/70 2.52 0.55 0.23
It is also understood on comparing results of Table II with that of Table III that just by addition of 2 ppm of TIPA in 200 ppm of the mixture of QM and 4-HT in various weight ratios (prior art additive), the % polymer formed is either same or better than the prior art additive consisting of 400 ppm of the mixture of QM and 4-HT in various weight ratios which further confirms that just an addition of 2 ppm of TIPA in 200 ppm of prior art additive composition results in substantial saving of 200 ppm of prior art additive consisting of aromatic compound and nitroxide compound at various weight ratios.

The above findings confirm that present composition is more economical and environment friendly than prior art composition consisting of aromatic and nitroxide compounds.
The above findings also confirm synergistic, surprising and unexpected effects of present composition.
Above experimental results also confirm that presently provided composition is far superior than prior art additive composition, and hence, has technical advantages and surprising effects over the prior art additive.