DE1045373B - Use of phosphonic acids - Google Patents

Description

Use of phosphonic acids It is already known that pyro- and poly phosphates are suitable as complexing agents for low-grade metals. These However, phosphates have the disadvantage that with increasing p-values and temperatures hydrolyzed to ineffective o-phosphorous acid. They are therefore only very limited applicable.

It is also known to use polyphosphonates - made from e.g. B. Ethulene diamine or its N-alkyl compounds or its N-, N'-diacetic acid and 2 moles of chloromethylphosphonic acid - to be used as a complexing agent. Critical to the effectiveness of these compounds is the combination of a phosphonate with an amino group. Only the introduction of this Amino group with the free electron pairs enables complex formation.

In contrast, nitrogen-free polyphosphonates are usually not Complexing agents, such as, for example, the compounds lithane-1,2-diphosphonic acid and Show propane-1,3-diphosphonic acid.

It has been found that diphosphonic acids and phosphonic carboxylic acids, whose functional groups are only linked by a C H2 group. or their Alkali salts are particularly suitable as complexing agents.

The phosphonic acids can be classified according to various known per se Process. For example, you can from chloroacetic acid alkyl esters by Sales with trialkyl phosphites obtained the trialkyl phosphonoacetate, the in the saponification the phosphonoacetic acid gives in a smooth reaction. One can also Halogen esters, such as. B. Chlofmethylphosphonsäure dialkyl ester, with alkali dialkyl phosphites Condense to diphosphonic or phosphonic acid esters and these in the usual way Way to saponify the acids.

The nitrogen-containing polyphosphonates have compared to the invention Phosphonic acids have the disadvantage that they are more difficult to access. Detrimental to the nitrogen-containing phosphonates, it is also that they z. B. in the presence of acids fail at about Pn 2 and become completely ineffective.

The phosphonic acids present, in particular methylene-diphosphonic acid, as such or in the form of their alkali metal salts, they have cations other than those of the alkali metals excellent to bind complex. The ions are so strongly masked in the complexes, that they no longer give numerous chemical reactions.

For example, the Fe3 + complex gives the methylenediphosphonic acid with Rhodanide no red color, the corresponding Caldum complex with ammonine moxalate none Precipitation. It is of particular importance that the phosphonic acids mentioned according to the invention in aqueous solution completely temperature and p-loading are constantly, so in this one Relationship are not subject to any restrictions in their application such as pyro- or polyphosphates. Compared to the latter, they also have the great advantage of being stronger Complexing ability. which is why in practice much less phosphonates than Needs to use phosphates. The calcium binding capacity was determined in the way that 10 g of complexing agent in aqueous solution is titrated with 0.5 N calcium chloride solution were using ammonium oxalate as an indicator until turbidity appeared by calcium oxalate.

1 g Na pyrophosphate binds 18.6 mg calcium ions; 1 g sodium tripolyphosphate binds 61.0 mg calcium ions; 1 g of disodium methylene diphosphonate binds 99 mg of calcium ions.

In general, concentrations of about 0.01 to 1 are used ovo off. The diphosphonic and phosphonic carboxylic acids or their salts can be used anywhere be used with advantage in industrial processes in aqueous medium, where interference is caused by foreign ions. They can be used as temperature and p-resistant Water softeners can be used. As an additive to solid and liquid soaps, detergents, Cosmetic items, hair shampoos and other cleaning products stop them in sufficient concentration, the formation of sparingly soluble metal soaps, discoloration and becoming rancid and at the same time act as antioxidants and stabilizers of the Foam. In photographic practice, all can be achieved by using hard Water related disturbances are eliminated, e.g. B. developer solutions can be stabilized will. on Because of their ability to bind heavy metal salts, the diphosphonates and phosphonic carboxylates mentioned according to the invention are suitable for stabilizing peroxy compounds such as those used for cleaning and bleaching purposes are used to stabilize latices made of natural rubber or also synthetic products made from polystyrene, butadiene and others Ability for the same reason to inhibit autoxidation, such as B. of sulfite (hair bleaching), fats, oils, Proteins, gums, plastics, etc. In the display and for stabilization antibiotics such as penicillin can be used to advantage. In the leather industry With their help, leather discolouration (e.g. due to iron) and decay of the Avoid skins. In the hydrazine preparation, they have the effect of improving the yield like an additive of glue. In the electrolytic preparation of metals, the addition of called phosphonates because of their ability to bind foreign ions, favorable. In electroplating processes, they are superior to alkali cyanides because they are physiologically harmless and do not require the use of distilled water. As an additive to alkaline baths for the »finish« of metal objects as well as for Polishing of metal parts can be used to achieve good gloss effects, as they prevent the formation of sparingly soluble salts and soaps. Also for agricultural chemicals They can be used to advantage in numerous cases. So can that Soil missing trace elements particularly effectively supplied as phosphonate complexes will. Growth solutions and weedkillers, such as a-naphthylacetic acid and dichlorophenoxyacetic acid, which can be precipitated by hard water are kept in solution by the phosphonates mentioned. Because of their calcium binding capacity Like citric acid, they can inhibit blood clotting. In papermaking With their help, very white and easy-to-bleach papers can easily be produced. The phosphonates can be used to advantage in dyeing and in the preparation of dyes used to bind calcium, magnesium and heavy metal ions. That has with all the dyes, e.g. B. vat dyes, ice colors and azo dyes with the azo group or carboxyl group ortho-position oxy groups, meaning those with the ones mentioned Ions usually form poorly soluble salts, which leads to a reduction in yield and loss of authenticity, z. B. the rub and wash fastness can occur. Catalytic decomposition too Diazotized amines by traces of iron and copper ions can be with the mentioned Stop phosphonates. In the representation of chromating dyes they serve to remove traces of disruptive heavy metal ions, such as especially copper and Iron ions, to bind. Even when peeling off some dyes, such as. B. some You can use sulfur dyes and copper dyes to decopper with success be used. With the representation of strength, they prevent the foxing, so far it is caused by hard water or metals. Leave at the rayon display the disorders caused by lead ions can be remedied with the above-mentioned phosphonates. The FeS + complexes are suitable for the low-temperature polymerisation of plastics of the phosphonates mentioned according to the invention in combination with Fe2l + salts are excellent to initiate polymerization.

Claims (1)

PATENT CLAIM Use of phosphonic acids of the general formula X-CH2-PO3 H2, where X is -P OsH, or -CO2H, and their alkali salts as complexing agents for binding polyvalent metal ions in an aqueous medium. ~~~~~~~ Considered Publications: British Patent Nos. 703180, 703181, 744633.