Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-08-03
2001-07-10
Nutter, Nathan M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S219600, C526S232100, C526S236000, C526S259000
Reexamination Certificate
active
06258905
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to novel stabilized unimolecular initiator compounds which have utility as initiators for hydrocarbon polymerization reactions. In particular, the present invention relates to the stabilized unimolecular initiator compounds, methods for making such compounds and methods for polymerizing hydrocarbons using such compounds as initiators.
2. Description of Pertinent Art
Polymerization of unsaturated, substituted or unsubstituted, hydrocarbons in the presence of radical-forming polymerization initiator compounds is well known and widely practiced. In such polymerization reactions, a radical- forming polymerization initiator compound, (for example, benzoyl peroxide), is brought into contact with polymerizable hydrocarbon compounds, (for example, styrene), under conditions of temperature and pressure such that the radical-forming polymerization initiator compound splits into one or more radicals which then combine with molecules of the unsaturated hydrocarbons to form activated centers necessary for the start of a polymer chain. A large number of such radical-forming polymerization initiator compounds are known, including organic peroxides.
Such hydrocarbon polymerization reactions have been improved by addition of stable radical compounds, along with radical forming initiators, to polymerization systems or via reversible atom transfer reactions, for control of stability and concentrations of polymerization propagating radicals in the polymerization reaction mixtures. The improved polymerization reactions are referred to as “living radical polymerizations” The generally used stable radicals are 2,2,6,6-tetramethyl-1-piperridinyloxy, (TEMPO) and organometallic radicals.
Georges, M. K.; Veregin, R. P. N.; Kazmaier, P. M.; Hammer, G. K.:
Macromolecules
1993, 26, 2987.
Kato, M.; Kamigaito, M.; Sawamoto, M.; Higashimura, T.
Macromolecules
1995, 28, 1721.
Wang, J. S.; Matyjaszewski, K. J.
Am. Chem. Soc
. 1995, 117, 5614.
Matyjaszewski, K.
ACS Symp. Ser
. 1997, 665, 12.
A living radical polymerization is a radical initiated polymerization reaction where there is no chain transfer or chain termination. That is, the initiator radicals are all attached to the end of polymer chains and remain active even at complete consumption of all the hydrocarbon monomers. Upon addition of more polymerizable hydrocarbons, monomers or polymers, the attached radicals will initiate further polymerization under polymerization reaction conditions. Characteristics of living radical polymerizations are, (1) the polymers prepared have narrow molecular weight distribution, (polydispersity index, (M
W
/M
N
),<1.3), and (2) block copolymers can be readily synthesized by adding additional monomers to a polymer product of a living radical polymerization and bring ing the mixture to polymerization conditions, without addition of additional initiators.
The living radical polymerization reactions initiated with two component initiator-stable radical systems usually exhibit much slower polymerization rates because of the requirement for the presence of excess stable radicals in order to allow precise control of polymer structures and properties. Recent developments in living radical polymerization reactions allow synthesis of a wide variety of new polymers and, in particular, finctionalized polymers with predetermined molecular weights and properties.
Solomon, D. H.; Rizzardo, E.; Cacioli, P.
Chem Abstr
. 1985, 102221335 9
Rizzardo, E.
Chem. Aust
. 1987. 54, 32.
Colombani, D.
Prog. Polym. Sci
. 1997, 22, 1649.
Georges, M. K.; Veregin, R. P. N.; Kazmaier, P. M.; Hammer, G. K.
Macromol. Symp
. 1994, 88, 89.
Recently, stabilized unimolecular initiators have been developed for use in initiating living radical polymerizations. These stabilized unimolecular initiators have facilitated construction of complex macromolecular architectures. The primary stabilized unimolecular initiator compound is:
1-benzyloxy-2-phenyl-2-( 2′2′,6′,6′-tetramethyl-1-piperidinyloxy) ethane (1)
Hawker, C. J.
J. Am. Chem. Soc
. 1994, 116 11185
Braslau, R.; Burrill, L. C., II; Siano, M.; Naik, N.; Howden, R. K.; Mahal, L. K.
Macromolecules
1997, 30, 6445.
The stabilzed unimolecular initiator,(1) above, is the reaction product of benzoyl peroxide, styrene, and 2,2,6,6-tetramethyl-1-piperidinyloxy. The synthesis reaction requires a large excess of styrene, prolonged reaction at elevated temperature and extensive isolation and purification processes. The low yield, (~40%), has limited practical commercial use of stabilized unimolecular initiator (1).
SUMMARY OF THE INVENTION
Now, according to the present invention, We have discovered novel stabilized unimolecular initiators and methods for their synthesis, which initiators have utility in polymerization, particularly living radical polymerization, of polymerizable hydrocarbons.
The stabilized unimolecular initiators of the present invention comprise the reaction product of a radical-forming polymerization initiator compound and a stabilized radical compound. Such stabilized unimolecular initiators may be economically synthesized under moderate reaction conditions and recoverd in good yield for use in large scale synthesis of hydrocarbon polymers.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
The stabilzed unimolecular initiators of the present invention are each the reaction product of a radical-forming polymerization initiator compound and a stabilized radical compound.
The radical-forming initiator compounds useful for synthesis of the stabilized unimolecular compounds of the present invention are those which initiate chain polymerization reactions of polymerizable hydrocarbon compounds. The stabilized radical compounds are those which, when reacted with a radical-forming polymerization initiator compound, form reaction products, (the stabilized unimolecular initiators), which will initiate chain polymerization reactions among polymerizable hydrocarbon compounds.
Many radical-forming initiator compounds are known. Useful in the present invention are those radical-forming polymerization initiator compounds which, upon reaction with stable radical compounds, form stabilized unimolecular initiator compounds which will initiate polymerization chain reactions among polymerizable hydrocarbons. Non limiting examples of such radical-forming polymerization initiator compounds useful in the present invention are organo peroxides and azo compounds. For example:
benzoyl peroxide; acetyl peroxide; dilauroyl peroxide;
succinic acid peroxide, dicumyl peroxide; di-tert-butyl peroxide;
2,4-dichlorobenzoyl peroxide; isononanoyl peroxide; decanoyl peroxide;
propionyl peroxide; 2,2-bis(t-butylperoxybutane); dibenzyl peroxydicarbonate;
dicyclohexyl peroxydicarbonate;
2,2′-azobisisobutyronitrile; dimethyl 2,2′-azobisisobutyrate; 2,2′-azobis(2-methylbutyronitrile);
and 1,1′-azobis(1-cyclohexanecarbonitrile).
Stable radical compounds useful in the present invention are those which react with radical-forming polymerization initiator compounds to form stabilized unimolecular polymerization initiator compounds. The stable radicals useful in the present invention are those which cannot initiate the polymerization of hydrocarbons by themselves in the reaction conditions, but which can combine with the radical-forming initiators useful in the present invention. Non limiting examples of stabilized radical compounds which may be used in the present invention include:
2,2,6,6-tetramethyl-1-piperidinyloxy;
4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy;
4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxybenzoate;
4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxymesylate;
4-amino-2,2,6,6-tetramethyl-1-piperidinyloxy;
N-(2,2,6,6-tetramethylpiperidine-1-oxy-4-yl)maleimide;
succinimidyl 2,2,5,5-tetramethyl-3-pyrroline-1-oxy-3-carboxylate;
4-(N,N-dimethyl-N-(sulopropyl)) ammonium-2,2,6,6-tetramethyl-piperidine-1-oxyl;
di-tert-butylnitroxide.
The stabilized unimolecular initiators of th
Wang Dekun
Wu Zhe
Asinovsky Olga
Nutter Nathan M.
LandOfFree
Stabilized, unimolecular initiators for hydrocarbon... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stabilized, unimolecular initiators for hydrocarbon..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stabilized, unimolecular initiators for hydrocarbon... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2527999