Organic compounds -- part of the class 532-570 series – Organic compounds – Rare earth containing
Reexamination Certificate
2002-02-19
2003-12-16
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Rare earth containing
C549S220000, C556S001000, C556S069000, C556S076000, C556S182000, C560S057000, C560S096000, C568S828000, C568S832000
Reexamination Certificate
active
06664380
ABSTRACT:
The present invention relates to catalyst compounds and processes for carbon-carbon bond formation, and particularly for alkene or aromatic acylation, alkoxylation or alkylation reactions.
The most widespread of these reactions is the Friedel-Crafts reaction, the activating agents for which are relatively low cost and enable a wide variety of organic manufacturing processes. Other reactions include the Diels-Alder and Kondakov reactions.
These reactions however present the manufacturer with a number of challenges, including the handling of raw materials, the handling of solvents, process conditions and effluent control. For example, such reactions often require the use of acyl halides, Lewis acid activating agents (typically AlCl
3
, TiCl
4
, BF
3
) and halogenated solvents. The handling of these can present significant health, safety and environmental problems, especially for the batch processing typically used by smaller companies or for smaller quantity production.
Also because the activating agent is typically decomplexed from the product by the use of water, there is a considerable amount of aqueous effluent generated, which must be treated to be environmentally acceptable.
Furthermore, the activating agent, although sometimes called a catalyst, is not a true catalyst since it usually has to be present in more or less stoichiometric amounts, and the decomplexing hydration effectively renders the agent non-reusable.
There have been proposals for various catalysts and processes as substitutes, and although some of these have had limited success for specific starting materials or types of starting materials, there has been no proposal of which we are aware which would be generally applicable over a wide range of starting material, which would use truly catalytic materials and quantities and which would not pose other problems as severe as those encountered in the classical Friedel-Crafts situation.
Reviewing current industrial practice in more detail, typical raw material feedstocks are (1) substituted aromatics (alkylbenzenes, tetralins, naphthalenes, thiophenes, phenols), alkenes; (2)acylating agents—acyl halides (acetyl chloride, benzoyl chloride), acyl anhydrides, epoxides (ethylene/propylene oxide) and fatty acids; (3) Lewis acids—(AlCl
3
, TiCl
4
, BF
3
) and (4) solvents—such as dichloroethane/methane, chlorobenzene and nitro-solvents.
A generic example is as follows:
Typically, alkenes or substituted aromatics are reacted in the presence of a Lewis acid activating agent with an acyl chloride or anhydride to give ketones, or with an epoxide to give an oxalkylated product. The Lewis acid is present in at least stoichiometric amounts and the reactions nearly always require a polar solvent.
Strictly speaking the Lewis acids (typically AlCl
3
, TiCl
4
) used are not true catalysts as they are used in stoichiometric amounts or more. This is because they form complexes with product compounds which are more strongly bonded than with the reagents and this requires a destructive method (aqueous hydrolysis) of retrieving the product, so the Lewis acids are non-recoverable.
AlCl
3
, TiCl
4
and FeCl
3
have the advantage of ready economic supply. Other more exotic and expensive Lewis acid catalysts are used in different parts of the chemical industry.
A Friedel-Crafts acylation reaction will end up with the product as a complex with the Lewis acid activating agent. These complexes are solids if isolated (which is unusual) but in practice the polar solvent typically employed keeps them in liquid phase and prevents potential abrasion of the reactor wall. The products are liberated by the addition of water which also reacts with the freed activating agent to generate a large volume of a non-recoverable effluent stream.
The acyl halides and Lewis acids are moisture-sensitive with the risk of liberation of hydrogen halides (usually as hydrogen chloride). Additionally, solid Lewis acids can present both dust and mechanical erosion problems. Reactions tend to be very fast and the time taken is directly related to heat removal from the plant. They are normally run in semi-batch mode to deal with their exothermicity, with efficient cooling or low boiling solvent reflux to take the required heat out of the system.
Reaction mixtures are usually quenched into water/ice to break the complex of catalyst and product. The resulting aqueous effluent has to be treated. Products are then recovered by solvent extraction, considerable washing (hence more effluent), solvent recovery and recrystallisation or distillation to purify the product, incurring relatively high energy costs.
Waste disposal for these reactions is expected to be subject to more stringent legislation, and to be a source of increasing cost. Waste disposal methods vary, but normally the major waste is precipitated metal hydroxide/salts, which goes to landfill unless an alternative use, e.g. as a flocculating agent, can be found.
Existing plant can be used for these reactions provided it is acid-resistant (especially to HCl). This generally rules out stainless steel and the ideal is glass-lined equipment.
The problems with these reactions are well known, and various solutions have been proposed—see for example Pearson & Buehler, “Friedel-Crafts Acylations with Little or No Catalyst”, Synthesis, 1972, 533-542. Success has been limited, usually with a catalyst being found suitable only for one substrate/agent, or only in very specific conditions.
An ideal solution to the problems would include as many as possible of the following criteria:
1) the reaction should be truly catalytic, preferably giving desired selectivity
2) the catalyst should (a) not form a strong complex with the product (b) be recyclable (c) have no deleterious effect on the end product (d) not be limited by mass transfer problems
3) non-halogenated reagents could be used e.g. acids, esters or anhydrides
4) no solvents or only non-halogenated (preferably hydrocarbon) catalyst solvents would be preferable, though a fluorinated solvent would be acceptable if not soluble or can be rendered insoluble in or immiscible with the organic reaction phase.
Where there is no carboxy group in the product, as in alkylation, complexation will frequently not be a problem; but most of the other criteria apply.
The present invention is concerned with fluorinated sulfonyl compounds and their use in catalysis.
Nishikido et al, Synlett, 1998, 1347 have disclosed a lanthanide compound—ytterbium triflamide, Yb[N(SO
2
C
4
F
9
)
2
]
3
—as a catalyst, which may be used in catalysis of Friedel-Crafts and Diels-Alder reactions. See also Zhu, Synthesis, 1993, 953.
WO-A-97/11930 shows Bismuth triflate, Bi(OSO
2
CF
3
)
3
, as a catalyst. Kobayashi et al, Synlett 1994, 545 have demonstrated that lanthanum and hafnium triflates are catalysts for Friedel-Crafts acylation reactions.
Turowsky & Seppelt, Inorg. Chem., 1988, 27, p2135, have disclosed the preparation of HC(SO
2
CF
3
)
3
.
In the Journal of Organic Chemistry 1999, 64, p2910, Waller et al disclose the compounds Yb and Sc [C(SO
2
CF
3
)
3
]
3
, as aromatic nitration catalysts. They name the compounds “triflides”. They also disclose a method for their synthesis.
The present invention utilizes, to fulfil one or more of those desirable criteria listed above, the use of a fluorosulfonylmethide compound represented by the formula I:
M[C(SO
2
R
1
)
3−(m+q)
(SO
2
R
2
)
m
(SO
2
R
3
)
q
]
x
where
M is H, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Zr, Hf, Th, Nb, Ta, U, Bi, Al, Ga, In or Tl
x is the common oxidation state of a said metal M
R
1
, R
2
and R
3
are perfluorinated or polyfluorinated hydrocarbon, ether or amine moieties
and m+q=0, 1, 2 or 3 (m and q being zero or integers)
as catalyst in a C—C bond formation reaction and in particular an acylation, alkylation or alkoxylation reaction.
The compound is used in catalytic quantities, for example 10 mol % or less based on the substrate of the reaction. Amounts of 5 mol % or less are effective, down to 1 mol % or below o
Barrett Anthony Gerard Martin
Braddock David Christopher
Chadwick David
Morgan & Lewis & Bockius, LLP
Nazario-Gonzalez Porfirio
The Institute of Applied Catalysis
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