Polycarboxylic acids, preparation thereof and use thereof...

Details Polycarboxylic acids, preparation thereof and use thereof... Polycarboxylic acids, preparation thereof and use thereof...

2001-01-17

2003-08-26

Raymond, Richard L. (Department: 1623)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acids and salts thereof

C562S523000, C562S526000, C562S524000

Reexamination Certificate

active

06610884

ABSTRACT:

The invention relates to acid-stable polycarboxylic acids, to a process for their preparation by oxidative cleavage of double-bond compounds with hydrogen peroxide or hydrogen peroxide donors, to the use of the polycarboxylic acids for treating cellulosic fibres or textile or paper materials produced therefrom and to the thusly treated cellulosic fibres, textile materials or paper materials.
Textiles made of cellulosic fibres such as cotton have the advantage over synthetic fibres of being hydrophilic, which manifests itself in high moisture absorption and good wear comfort. The reason for the high moisture absorption is the swellable amorphous regions in cellulosic fibres. However, cellulose swollen by washing or perspiration wrinkles and has to be smoothed again by thermal and mechanical treatment. In addition, cotton shrinks on washing, causing textiles to lose their original shape. To control these disadvantages, cellulosic fibres have for many years been treated with products which, by reacting with the hydroxyl groups of the cellulose, partly crosslink the amorphous parts of the fibres. Owing to this treatment, the textile retains its shape on wearing and washing. Preferred crosslinkers are methylolated urea or melamine derivatives. The disadvantage with these compounds is that they may release formaldehyde in the course of the finishing and use of the textile.
There has therefore been no shortage of attempts to find alternative and ecologically better products for treating textiles. The use of polycarboxylic acids such as butanetetracarboxylic acid for formaldehyde-free textile finishing is known in principle from Text. Res. J. 37, 933 (1967) and U.S. Pat. No. 4,820,307.
It is likewise already known in principle that polycarboxylic acids may be prepared by oxidative cleavage of compounds containing double bonds. For instance, butanetetracarboxylic acid can be prepared by oxidative cleavage of tetrahydrophthalic acid using nitric acid under vanadium catalysis (J. Org. Chem. 30, 1488 (1965), DE-A-30 16 225, JP 59128350 A2). This process is disadvantageous because of the aggressive reaction conditions causing some of the starting materials used and of the intermediate and end products to be decomposed by further oxidation reactions. In addition, toxic nitrogen oxides escape in the course of the reaction and can only be removed by an inconvenient gas scrub. The process by-produces nitrogenous compounds which, in the use as textile crosslinkers, lead to noticeable yellowing of the finished fabric and are removable only by inconvenient recrystallizing.
Therefore, hydrogen peroxide is a more suitable oxidizing agent, since its use gives rise to just water as reaction product. U.S. Pat. No. 3,646,130 describes the oxidative cleavage of cyclododecene with hydrogen peroxide using Re
2
O
7
as catalyst. EP-A-0 122 804 discloses the oxidative cleavage of various olefins with hydrogen peroxide using a catalyst prepared from H
2
WO
4
, H
3
PO
4
and a phase transfer catalyst. In EP-A-0 123 495 various intermediates obtainable by dihydroxylation of olefins are cleaved to the corresponding carboxylic acids using hydrogen peroxide and a catalytic system composed of H
2
WO
4
and H
3
PO
4
.
EP-A-0 513 600 describes preparing carboxylic acids by oxidative work-up of olefins reacted with ozone. This reference too mentions preparing butanetetracarboxylic acid from tetrahydrophthalic anhydride. But the disadvantage with this process is the use of toxic ozone, which, moreover, is energy-intensive to prepare.
U.S. Pat. No. 5,047,582 describes the preparation of polycarboxylic acids in a two-step process. The first step is the conversion, in a non-catalyzed process, of an olefin into the corresponding dihydroxy compound which, in a second step, is cleaved by the use of various transition metal catalysts into the corresponding polycarboxylic acid.
EP-A-0 201 719 discloses preparing polycarboxylic acids such as butanetetracarboxylic acid by oxidative cleavage of olefins such as tetrahydrophthalic anhydride with hydrogen peroxide using a catalyst selected from tungstic acid, molybdic acid and heteropolyacids thereof.
EP-A-0 688 897 describes the oxidative cleavage of tetrahydrophthalic anhydride with hydrogen peroxide to form butanetetracarboxylic acid and also the use of the thusly obtained butanetetracarboxylic acid for treating cellulosic fibres.
JP 08295649 A2 describes preparing butanetetracarboxylic acid by using tungsten compounds combined with nitrogenous heterocyclic carboxylic acids as oxidation catalysts.
One disadvantage with the above-described background art is that the butanetetracarboxylic acid obtained does not possess adequate acid stability in the aqueous reaction solutions produced. The consequence is that some of the butanetetracarboxylic acid separates as a solid, the rest remaining dissolved in the aqueous phase. But such solids-containing solutions are unsuitable for treating fibres or textile materials. The butanetetracarboxylic acid therefore has to be first completely isolated by evaporating the water. This, however, is energy-intensive and hence not economical. In addition, crosslinkers in the form of solids are not very attractive; the most commonly used crosslinkers for cellulose are offered as aqueous solutions because of their better handlability. These disadvantages are the reason why polycarboxylic acids such as butanetetracarboxylic acid have hitherto not found commercial application for finishing cellulosic fibres or textile materials produced therefrom.
It is accordingly an object of the present invention to provide a process for preparing polycarboxylic acids that possess sufficient acid stability in aqueous solution and are suitable for crosslinking cellulosic fibres.
This object is achieved by a process for preparing polycarboxylic acids by
1) reacting compounds of the formulae (I) or (II)
where
R
1
and R
2
are identical or different and each is H or straight-chain or branched C
1
-C
5
-alkyl,
with compounds of the formula (III)
R
3
XH  (III)
where
x is O, NH or S and
R
3
is straight-chain or branched C
1
-C
30
-alkyl, straight-chain or branched C
2
-C
30
-alkenyl, C
5
-C
12
-cycloalkyl, —CHR
4
COOH
 where
R
4
is H, straight-chain or branched C
1
-C
5
-alkyl, —CH
2
OH, —CH(OH)COOH or —CH
2
COOH,
 or
—(CH
2
CR
5
R
6
Y)
n
R
7
,
where
Y is O or NR
8
,
R
5
, R
6
, R
7
and R
8
are independently H, straight-chain or branched C
1
-C
4
-alkyl, —CH
2
OH or —CH
2
CH
2
OH and
n is an integer from 1 to 20
and
2) subsequent oxidation in the presence of hydrogen peroxide or of a hydrogen peroxide releaser and of a catalyst.
The invention further provides the polycarboxylic acids obtainable by this process.
The reactants used in the process of the invention are compounds of the formulae (I) or (II). They are tetrahydrophthalic acid, tetrahydrophthalic anhydride or appropriately substituted derivatives thereof. R
1
and R
2
are identical or different and are each preferably hydrogen or methyl in the formulae (I) and (II). Particular preference is given to using 1,2,3,6-tetrahydrophthalic anhydride for the reaction with compound (III).
The compounds of the formula (III) used in the process of the invention can be monofunctional, bifunctional, trifunctional or more highly functional, depending on which of the indicated meanings are assigned to R
3
.
Preference is given to using at least bifunctional compounds of the formula (III) where
X is O and
R
3
is —CHR
4
COOH,
where
R
4
is H, straight-chain or branched C
1
-C
5
-alkyl, —CH
2
OH, —CH(OH)COOH or —CH
2
COOH, or —(CH
2
CR
5
R
6
Y)
n
R
7
,
where
Y is O or NR
8
and
R
5
, R
6
, R
7
and R
8
are independently H, straight-chain or branched C
1
-C
4
-alkyl, —CH
2
OH or —CH
2
CH
2
OH and
n is an integer from 1 to 10, preferably from 1 to 5.
Particular preference for use as bi- or trifunctional compounds of the formula (III) is given to the use of ethylene glycol, diethylene glycol, triethylene glycol, lactic acid, glycerol, trimethylolpropane or 2,2-bis(hydroxymethyl)propionic acid.
In a preferred

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