Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
2002-05-03
2003-03-25
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S407000, C564S347000
Reexamination Certificate
active
06538158
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a process for preparing 1,4-diaminonaphthalene and/or 1,5-diaminonaphthalene from naphthalene.
1,4-diisocyanatonaphthalene was mentioned for the first time in the literature as a starting material for polyurethanes in Ann. Chem. 562, 6 (1949). Due to the lack of a cost-effective manufacturing process for 1,4-diaminonaphthalene and hence for 1,4-diisocyanatonapththalene, only a few areas of application for 1,4-diisocyanatonaphthalene are described in the literature. Examples of such areas of application are the preparation of polyurethane-based adhesives or fiber additives, which are disclosed in JP-A2-52096295 and DE-A1-2403656.
An isocyanate component used for the preparation of naphthalene-based polyurethane according to the prior art is mainly 1,5-diisocyanatonaphthalene, which is used in the preparation of polyurethane elastomers.
1,5-diisocyanatonaphthalene is prepared industrially by the phosgenation of the corresponding diamine 1,5-diaminonaphthalene. In accordance with the prior art, 1,5-diaminonaphthalene is prepared via the sulfonation of naphthalene and the subsequent substitution of the sulfonic acid groups with amino groups (DE-C1-3840618).
1,4-diaminonaphthalene, on the other hand, is reacted with 1,4-naphthalene diisocyanate for the synthesis of polyamides, polyimides and polyimines, and also for the preparation of conductive or electro-luminescent polymer materials, as described, for example, in the patent specifications JP-A2-06346050 and JP-A2-07022670.
Preparation of 1,4-diaminonaphthalene in accordance with the prior art is currently limited to preparation by azocoupling starting with 1-naphthylamine (JP-A2-51133237, Rev. Farm. Bioquim. Univ. Sao Paolo (1977), 15 (1-2), 19-25) and via the reaction of hydroxylamine with nitronaphthalene in strongly alkaline medium to form 1-nitro-4-aminonaphthalene (J. prakt. Chem. 156, 315 (1940), Chem. Ber., 22 (1899) 1374). These processes represent multi-stage syntheses with high production costs and low yields in addition to cost-intensive raw materials.
Polyurethanes based on 1,4-diisocyanatonaphthalene and 1,5-diisocyanatonaphthalene possess advantageous properties, so that a practicable synthesis routes for the preparation of 1,4-diaminonaphthalene and 1,5-diaminonaphthalene and their corresponding isocyanates are required.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a simple process for the preparation of 1,4-diaminonaphthalene and/or 1,5-diaminonaphthalene.
This and other objects which will be readily apparent to one skilled in the art are accomplished by reacting naphthalene with a halogen and reacting the halogenated naphthalene with ammonia and/or an organic amine, optionally, in the presence of a catalyst.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a process for preparing 1,4-diaminonaphthalene and/or 1,5-diaminonaphthalene by
a) reacting naphthalene with a halogen,
b) optionally, separating 1,4-dihalogen naphthalene and/or 1,5-dihalogen naphthalene from the mixture from step a),
c) re acting the mixture from step a) or the 1,4-dihalogen naphthalene and/or the 1,5-dihalogen naphthalene from step b) with ammonia and/or an organic amine in the presence of a catalyst.
The selective dihalogenation of naphthalene can take place in the absence of a catalyst or it may be catalyzed but it is preferably catalyzed.
If a catalyst is used, suitable catalysts for the dihalogenation reaction include iodine, tin, elements of Groups 8, 10, 12 and 13 of the Periodic Table (nomenclature to I.U.P.A.C 1985), mineral acid salts and oxides of the elements of Groups 8, 9, 10, 12, 13, 14 and 15 of the Periodic Table (nomenclature to I.U.P.A.C 1985) and mineral acids.
Preferably, iodine, iron, tin, zinc, aluminum, nickel, halides or oxides of iron, nickel, aluminum, antimony, arsenic, tin, zinc, boron or phosphoric acid are used.
Suitable halogens include chlorine, bromine and mixtures thereof.
In principle, any solvent which is able to dissolve naphthalene and is not halogenated to a significant extent under the prevailing conditions may be used in the process of the present invention. Dichloromethane, trichloromethane, tribromomethane, tetrachloromethane, tetrabromo-methane, chlorobenzene, dichlorobenzenes and trichlorobenzenes are preferred. Most preferred is trichloromethane.
The procedure adopted for the dihalogenation is preferably such that the halogen, preferably bromine, is introduced into a mixture of naphthalene, solvent and catalyst at an absolute pressure in the range of from about 0.5 to about 10 bar, preferably from 1 bar to 2 bar, most preferably from 1 bar to 1.2 bar, and at a temperature in the range of from 0° C. to 150° C., preferably from 10° C. to 70° C., most preferably from 20 to 30° C. The naphthalene concentration during the halogenation is preferably in the range of from 5 to 70 wt %, most preferably from 25 to 50 wt %, based on the weight of the solvent.
During the dihalogenation, a mixture containing 1,4-dihalogen naphthalene and 1,5-dihalogen naphthalene is obtained. Prior to amination, the mixture may be purified. The 1,4-dihalogen naphthalene and/or the 1,5-dihalogen naphthalene can also, however, be separated out of the mixture. The 1,4-dihalogen naphthalene or the 1,5-dihalogen naphthalene can be aminated free from isomers in this way.
The separation of the 1,4-dihalogen naphthalene and/or the 1,5-dihalogen naphthalene out of the mixture can be accomplished by taking advantage of the large melting point difference of these isomers, for example, by crystallization.
The halogen-amine substitution is performed in the presence of a catalyst. Suitable catalysts include any of the metals of Groups 8, 9, 10 and 11 of the Periodic Table (nomenclature to I.U.P.A.C 1985) and oxides, acetates and mineral acid salts of metals of Groups 8, 9, 10 and 11 of the Periodic Table (nomenclature to I.U.P.A.C 1985).
The metal catalyst can be in the form of granules, chips, powder or fixed to a support, for example on aluminum oxide, silicon oxide or titanium oxide, or in any other solid form. The chlorides, acetates and oxides can be used, for example, in the form of pellets or as powder or fixed to a support such as aluminum, silicon or titanium oxide.
Preferably nickel, copper, cobalt or iron metal, halides of iron, nickel, copper, cobalt, oxides of iron, nickel, copper, cobalt, acetates of iron, nickel, copper, cobalt are used.
In principle, any solvent which is able to dissolve dihalogen naphthalene and is inert under the prevailing conditions may be used in the process of the present invention. Preferably, water, methanol, ethanol, N,N-dimethyl acetamide, n-propanol, n-butanol, acetonitrile, benzonitrile, dioxan or dioxan/water mixtures or inert solvents which are immiscible with water such as toluene, xylene or aliphatic or cycloaliphatic hydrocarbons of the C
6
-C
12
fraction are used. The use of liquid ammonia as a reaction medium without further solvent addition is also suitable for the amination reaction of the dihalogen naphthalene.
Ammonia as well as any primary and/or secondary amines such as monoalkyl amines, monoacyl amines or dialkyl amines are suitable as amination agents. Ammonia is preferably used.
The yield of the halogen-amine substitution reaction in terms of diamino-naphthalene can be raised considerably if the hydrohalic acid formed, during the reaction is neutralized with a base. Suitable bases include carbonates and hydroxides of Groups 1 and 2 of the Periodic Table (nomenclature to I.U.P.A.C. 1985). Preferably, sodium, potassium, calcium or magnesium carbonate or hydrogencarbonate or sodium, potassium, calcium or magnesium hydroxide or mixtures or mixed crystals thereof are used. The addition of cesium, rubidium or barium chloride, cesium, rubidium or barium sulfate improves the yield-increasing effect of the base. Cesium chloride or cesium sulfate is preferably used.
The halogen-amine substitution is carried out at temperatures in the range of from 0° C. to 200° C., preferably
Duda Lothar
Hoffmann Andreas
Temme Bodo
Wegener Gerhard
Zechlin Joachim
Barts Samuel
Bayer Aktiengesellschaft
Gil Joseph C.
Whalen Lyndanne M.
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