DD213929A1 - PROCESS FOR PREPARING ETHANHYDROXYDIPHOSPHONIC ACID IN THE MIXTURE WITH PHOSPHORIC ACID - Google Patents

Abstract

The aim and the object of the invention is to process the by-products obtained in the phosphorus (III) oxide synthesis in a reaction stage into technically utilizable end products and thereby to obtain a favorable economy for the process route of the preparation of P-organics from elementary phosphorus via intermediate P deep4 O deep6. It has been found that the phosphorus oxides or phosphorus oxide mixtures which are solid at temperatures> 25 ° C. and have an average oxidation number between 3 and 5 with acetic acid, if appropriate in the presence of moisture and acetic anhydride, in the weight ratio P component: acetic acid = 1: 2 to 1:20 are combined at temperatures <equal to 50 degrees C and the reaction mixture is reacted under Erwaermen up to temperatures of <equal to 150 degrees C for 10 minutes to 5 hours to Ethanhydroxydiphosphonsaeure and phosphoric acid. With the addition of Zn ions or other inhibitors, ready-to-use solutions for water treatment in circulatory systems can be obtained.

Description

Process for the preparation of ethane hydroxydiphosphonic acid in admixture with phosphoric acid

Field of application of the invention

The invention relates to a process for the preparation of ethane hydroxydiphosphonic acid in admixture with phosphoric acid.

The Ethanhydroxydiphosphonsäure (EHDP) takes üf.a · application as hardness stabilizer in water systems · With the addition of particular Zn un.d PO ₄ --Ionen result korrosionsinhibirende preparations for metal surfaces (DOS 1.9O2 * 651 _# 2 DOS. .850ί "925, DOS II", 767-454),

Characteristic of the known technical solutions

Synthesis processes for the preparation of the EHDP from the lower-order phosphorus oxide P ₄ O ₆ and further anhydrides of the P (III) oxides which are known from P ₄ O ₆ and H ₂ O are known. Formally construct H ₃ PO ₃ (US 3,400,149, GB I 145.608, GB 1,190,399, GB 1,39,844, VSP 106,654, WP 108,511, DOS 25,235n, 689).

The P (III) -coronate is reacted with acetic acid ", optionally in an inert solvent such as sulfones, sulfolanes and / or acetic anhydride to an intermediate product (condensed EHDP), which is then hydrolyzed by a steam treatment to EHDP svi r &'-'' .:

The economics of the process over the phosphorus (III) oxide

/ rrn jArtA. r »/« iVi "k η."

P ₄ O depends to a great extent by the recovery of by-products from "For the latter exists outside of the esterification reaction for P _A Q -mixtures (x = 7-9), no economically and technologically effective process, which of course from the composition applicable solids becomes. According to the hitherto known processes for preparing the phosphorus (II) oxide P ₄ Og, the proportions of by-products make up about 30 % and more (US Pat. No. 3,532,461, VVP 79.280, VVP 76.007, WP 26.660, US Pat. No. 3,652. 211, US 3,652,213, US 3,679,560). The by-products furthermore have highly sorptive egg J- properties, meaning they also hold large amounts of PO determines which makes distillation difficult to remove :.

Object of the invention

The aim of the invention is to create a favorable economy for the process route of the production of P-organics from elementary phosphorus via the intermediate P .Qc via a technologically simple processing of the by-products obtained in particular in the phosphorus (III) oxide synthesis

 4 6

) Presentation of the essence of the invention

The object of the invention is to achieve this processing in such a way that a technically utilizable end product is formed in a reaction stage and a simultaneous reaction of still adhering P ₄ Og quantities. is mitgewährleistet * According to previous references arise in the P-oxidation process, preferably xm f-lolverhältnis P ₄ ; O ₂ = 1: 3 {P ₄ 0 ₆ synthesis), as by-products PCIIIiVj-oxide mixtures of an average composition between P ₄ O _{7 2} and P ₄ O _{8 5} and to a small extent simultaneously water-insoluble phosphorus suboxides in addition to small amounts of unreacted white phosphorus ,

In the preparation of P-oxides by hot flame reaction (temperature> 500 ⁰ C) by reacting P ₄ with oxygen in the molar ratio P.: O _n = 1: 2 to 1: 4, preferably of P ₄ : Q ₂ = 1: 3, in plants exceeding the laboratory scale (100-200 g / h), it was found that under certain operating conditions (insufficient turbulence of the reaction components P ₄ and oxygen and too long or too short quenching) in addition to the substances just mentioned (phosphorus (III, V) oxides, phosphorus suboxides) further solid by-products of other more complex composition arise. The resulting solid reaction products were analyzed in various ways (Example 1). Depending on the conditions of presentation, the composition of these by-products varies. "The interpretation made with regard to the possible structure of the substances in the individual analysis fractions does not limit the inventive concept. The analytical results listed, however, indicate the complicated and confusing structure, so that similar to the Reaction of P ₄ rait O ₂ and acetic acid according to GB 1,138,238, in which pyrophoric by-products are formed (B. Blaser et al., Z. anorg, Allg. Chera., 381, 247-259 (1971)), with a large number of reaction products was to be expected.

Surprisingly, it was found that in the reaction of P-0-containing, at room temperature above 25 ⁰ C solid compounds having a mean Gxydationszahl between 3 and 5, in a hot flame reaction at temperatures> 500 ⁰ C in the reaction of P ₄ and Oxygen (O ₂ ) in the molar ratio P ₄ : O ₂ = 1: 2 to 1: 4, preferably 3, optionally in the presence of inert gases such as N ₂ , and a rapid quenching to temperatures <400 ⁰ C in <10 see, preferably <1 see :, are obtained as by-products, with acetic acid optionally in the presence of moisture and

Acetic anhydride, in weight ratio P-koraponente; Acetic acid = 1: 2 to 1: 20, preferably 1: 5 to 1: 15, at temperatures ^, 50 ⁰ C and the following steps:

Optionally, separating the insoluble in acetic acid products such as phosphorus suboxides

- Heating the reaction mixture to temperatures of 150 ⁰ C, preferably to the boiling point of acetic acid, 10 min to 5 h, preferably 30 min to 2 h

- Separating excess acetic acid at temperatures up to 150 ⁰ C, optionally by applying negative pressure

- Hydrolysis of the intermediate obtained

- If necessary, filtration still insoluble in water components such as phosphorus suboxides

a mixture of ethane hydroxydiphosphonic acid and phosphoric acid is formed in the form of an aqueous solution which can be processed in a manner known per se. It proceeds zweckraäßigerweise so that the acetic acid in a teoperierbaren RührwerksbehäXter presented with RückfluBkühler under inert gas and the air-sensitive solid reaction products are added so that the temperature of the reaction sgetaisches 50 ⁰ C does not exceed. Before the subsequent heating process, the unreacted compounds consisting essentially of phosphorus suboxides can be filtered off. The further tempering is conveniently carried out by heating the acetic acid solution at reflux *. De according to de © chosen ratio P component: acetic acid separates a liquid phase, the ui.a. condensed phosphonic acid contains. The latter can be subjected to an Ifasser steam treatment. In the presence of a homogeneous acetic acid solution, excess acetic acid is separated off before the steam treatment

 By mixing in other components such as z * 3. Zn ions,

other inhibitors, dispersants, etc. can be easily prepared ready solutions for water treatment in circulatory systems. The process has the advantage that in a simple manner from previously unreachable or poorly usable reaction products, a high quality end product is produced · Ethanhydroxydiphosphonsäure and H ₃ PO ₄ could practically be identified as sole reaction products. The former, in particular in the case of incomplete hydrolysis, was partly present as a condensed product (5-10 %) before "d.hi, others not attributable to the EHDP and H, PO _A.

31 feeding reaction products could not be detected by P-NMR spectroscopy and paper chromatographic methods. Like the high P (V) content (compared to the P (V) value in the starting product), this is also surprising. The Struktureleraente listed in Example 1 as well as other well-known go in the reaction with the acetic acid and the selected reaction conditions virtually quantitatively in PC bound phosphorus of the EHDP grouping and pentavalent phosphorus (phosphates). Under analogous reaction conditions, virtually no P (V) content is formed in the reaction of pure P ₄ O ₆ with acetic acid.

Exemplary embodiments

The process is illustrated in the following examples: Example 1; Analytical Characterization of Byproducts Reacted in Example 2 An almost completely water soluble by-product of the P ^ Og synthesis with a P _Qes = 54.8 % (water insoluble fraction 0.1 %) was broken down into individual fractions. After extraction of the solid by-products by means of carbon tetrachloride, a residue which was taken up in water ("phosphorus (III, V) oxide ^M" fraction) remained, which contained 22 % of the total amount of phosphoric acid.

made. The P (III): P (V) - ratio was 10.6, -soluble from CCl ₄ fraction could be converted successively 20,25 and 2% of Gesaratphosphormenge in the aqueous phase at a three-time addition of water. By comparative analyzes it was possible to ensure that in the "P (III, V) oxide" fraction the P (III) P (V) ratio was only insignificantly influenced by P4O5 still adhering, the first water extraction stage being approximately equivalent to the P.Og ratio. Proportion corresponded and remained in the CCl. Phosphor phase contained only insignificant amounts of elemental phosphorus. With the aid of analytical methods of E. Thilo and D. Heinz (E. Thilo and D. Heinz, Z. Anorg, General Cherau 281, 303 (1955); D .. Heinz "Upper oxides of phosphorus with oxidation numbers less than V ", Dissertation, Humboldt University Berlin 1964) for the determination of P ¹ -, P ¹¹¹ -. and P ^V units in P ¹¹¹ -, *

pii2-oP ^V -, pu p ^V - and P ^ groups containing Strukturelefflenten that failed especially when CCl ^ -Fraktiotr let be deduced that obviously the P. Tetrahedron still largely in the -soluble in _CCl4 phosphorus oxides or is partially degraded by POP bonds and that in the "phosphorus (III, V) oxide" fraction in addition to the P .0 mixtures (X = 7-9) a polymeric PÄOi with P- € -P- Bindings in which statistically P (V) and PP units can be incorporated.

Example 2

100 g of the analyzed in Example 1 substance were langsasii registered containing in a -Γϊ 1000 g of acetic acid tempered Rührwerksgefäß with Rückflaßkühler at room tempera door · The resulting solution wcsrde of very small amounts of Phosphorsuboxiden filtered off and then erwärist _t being at temperatures of about · 90 ⁰ C an exothermic reaction is recorded. Under

Another 'sVärmezufuhr and stirring was further heated for one hour and then distilled off excess acetic acid in the Vakuurarotationsverdampfer, the temperature was raised to 130 ⁰ C. After a four-hour steam treatment of the acidic solution with 550 ml of 33% strength NaOH to a pH of 9, an aqueous product mixture was obtained which had the following analysis values in the dry matter:

P (III) = 1.0 %. P _{ges #} = 19.5 % a. P (V) = 3.1 %.

In the P-NMR were Spektrura except for a small amount of P (III) practically only two resonance signals in the pro- j tonenentkoppelten spectrum at -19.7 ppm (sodium salt of EHDP) and -2.4 ppm {Na ₂ HPO ₄₎ To recognize. A hinted at -15 to -16 ppm very weak signal could also be identified by means of paper chromatographic investigations as condensed EHDP (proportion ca, 5% of total phosphorus).

Example 3

265 g of a by-product of the P-Og synthesis with P _s = 56.7 %, P (Y) = 4.9 %, Phosphorsuboxidanteil = 1.3 % and a P (III): P (V) ratio in the "P (III, V) oxide" ~ fraction = 6.9: 1 was analogously to Example 1 in 600 g; Acetic acid at 30-40 ⁰ C registered. The mixture was then heated for 4 h, the bath temperature being 140 ° C. Excess acetic acid was distilled off at this temperature at the end by applying a vacuum. Subsequently, steam was introduced at this temperature for 4 hours and, after addition of activated carbon, the solution was filtered. By adding sodium hydroxide to pH = 9, a mixture of Na, ΞΗΟΡ and Na ₂ HPO _{4 was} prepared approximately. Cav was obtained 700 g of solid. It showed the following analyzes ::. P (III) _-1.1 %, _ηηο = 17.5 %, P (V) = 7.3 %. P-NMR spectroscopy and quantitative paper-chromatographic studies showed that The main reaction products include the Na salts of EHDP

<Γ = - 19.6 ppm and H ₃ PO ₄ at Γ = -2.3 ppm and about 5% of the total phosphorus can be detected as condensed EHDP.

Claims (2)

invention claim 1 · A process for the preparation of Eihanhydroxydiphosphonsäure in admixture with phosphoric acid, characterized in that at temperatures> 25 ⁰ C solid phosphorous oxides or Phosphoroxidgeraische having an average oxidation number between 3 and 5 with acetic acid »optionally in the presence of moisture and acetic anhydride, in the weight ratio P- Component: acetic acid = 1: 2 to 1: 20 at temperatures ^, 50 C are combined and the reaction mixture with heating to temperatures
5 hours is implemented ¹ . up to temperatures of ^ 150 ⁰ C for 10 minutes 2. A process for the preparation of Ethanhydroxydiphosphonsäure in admixture with phosphoric acid according to item 1, characterized in that are used as starting material at temperatures> 25 ⁰ C solid phosphorous oxides or phosphorus oxide mixtures having a mean oxidation number between 3 and 5, in hot Flamrareaktion at temperatures> - 500 ⁰ C in the reaction of P. with O ^ in the molar ratio.P ₄ : 0 ~ = 1 t to 1: 4, optionally in the presence of inert gas and a rapid quenching to temperatures <400 ⁰ C in <10 s than By-products were obtained.