DE2132026A1 - Process for the production of phosphonic acids - Google Patents

Description

DR. BERG DIFL.-ING. STAPF

PATENT LAWYERS β MUNICH 8O, MAUERKIRCHERSTR. 43

Df. Bra Dipl.-Ing. Stopf, 8 MBndiwi 80, Moiwrkifdnrttrofl «45 ·

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Your writing *

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Therefore

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Arrcaltsakte? 1 180 Be / Ro

üonsanto Company St. LouiB / tTSA

"Techniques for the production of phosphonic acids *

ΐ) ίο present invention relates to ancestors eur production of Pho3phon.3il.uren. and in Beaoncierert a verbeaaerteo process for the production of l-Iiydroxy-orsaro-II-Diiihoophonsäuron, ic particulars of the l-: iydroxj'-j: ieärisali ^ liden-l # l-Diphoaphonsiiuren, woboi ea for a continuous mode of operation

0-03-21-3062 109882/197 5

BATH ORIGINAL

-2-

suitable is.

liaoh the U.3.-Patent 3,449,410 lcönnsn. 1-Hydroxyorgäno-1,1-diphosphonic acids are advantageously produced by converting a lower, aliphatic-llonocarboxylic acid and a phosphorus fihalide (phosphorus tribroinide or phosphorus trichloride) according to a reaction sequence such that at least part of the organohalide (bromide or -chloridl by-product from the reaction as Eeaktionspartner to produce the desired phosphonic verv / ends ^w ". 17ach the teaching of this patent many and various advantages are achieved, including the production of" certain diphosphonic acids in high yield, eg · higher than approx " 97 $ and purity, such as with a content lower than about 3p H ^ PCU * In this patent specification it is stated many times that the process described there uses at least part of the organohalide by-product which is otherwise a waste product should be appreciated and that the process can be easily and selectively controlled.

While that described in U.S. Patent '3-449,409 Process has many advantages, is a technical process according to the production quantity or after manufacture des desired. To evaluate the end product per unit of time »Hence is the improvement within the framework of the aforementioned calibration line very desirable, especially if these do not require additional capital investments, and the

109882/1975

6AD.

vrlinselite achieve the final result.

ώα eats a main object of the present invention, an improved process en aur the production of l-hydroxy-or ^ ano-l, l-DipliospIionsäureii aur provide au.

Vo it or ο objects of the present invention are:

- 2 in the process for the preparation of l-kydroxy-organo-ll-biphosphonoacids, da3 for a continuous method of operation
suitable is.

- 3in verialiren on the production of l-Hydroücy-organo-l.l-Diph.ocphoiiGu.uren, daa increased production is linked to the Oil volume produced per unit of time in comparison with the process according to the state of the Sechnil.

In general, the process of the present invention consists in that nan (a) in a reactionsone has a lower
aliphatic ^ ilonocarboxylic acid and a phosphorus trihalide
(Phosphorus tribronide or phosphorus trichloride) "with formation
of a liquid Eealrcior product unsetst, (b) in the reaction zone this liquid product to elevated temperatures
heated while the organohalide by-product as
Gas removed from the reaction zone, (c) the liquid product is cooled and kept at a temperature lower than 60 ° C., (d) the cooled, liquid product in the reaction zone is up to 70% by weight of a llonocarboxylic acid (as above and below

defined), based on the total weight of the

-4-109882 / 1975

Step (a) unreacted monocarboxylic acid is added, (e) to the cooled liquid product and the added monocarboxylic acid, both of which are located in the reaction zone, up to 70 wt. Ia a phosphorous trihalide (as defined above), based on 'the total weight of phosphorus trihalide used initially in step (a) "with the proviso that the molar ratio of the acid added to the trihalide added is at least 2: 1, with the formation of additional liquid (reaction) product, (f) the liquid reaction product heated in the reaction zone to elevated temperatures while the organohalide by-product is removed as a gas from the zone, (g) at least a portion of the total (collected) organohalide by-product of the reaction zone for reaction with the liquid reaction product, whereby a normally solid, anhydrous reaction product is formed and (h) thereafter the desired product is a T-hydroxy-organo-1.1-diphosp Acid wins from the normally solid, anhydrous reaction product. -

In connection with the method described above, there are specific improvements over that in the U.S. patent 3,449,409 in steps (c) to (f) described above. It was unexpectedly found that using the improvement stages (c) to (f) the production amount of combined diphosphonic acid per unit of time substantially increased v / ird, for example up to 40 ^,

.1 0 9882/1 975

OBlG ^ AL

without the need for additional capital investment.

The above-mentioned production increase per. .Time unit, the results from the improvements of the present invention over the methods of US Pat. No. 3,449,40.9 completely unexpected, because it was to be expected that side reactions would occur if the second proportions or amounts of Phosphorus trihalide and honocarboxylic acid are added to the already formed liquid reaction product, the contains a large number of compounds described below, which are generally very reactive materials as such are.

With regard to the phosphorus trihalide-monocarboxylic acid reaction, the following course of action shows the overall reaction when phosphorus trichloride is used as the phosphorus trihalide reaction partner and the stoichionetric reaction partner is used :

0 ORO

// KO _n

, + 3 R-C-OH>

(II) - HO '

It _f H _f OH + Organochloride PCP _n ' By-product I. ^v 0H OH

-6-10 9 8 8 2/1975

wherein the radical R is an aliphatic group of 1 to about 1 6 is carbon atoms; Cbv / ohi the 2nd est R unsaturated hydrocarbyl groups, like äthyleniseii unsaturated hydrocarbyl groups (Alkenyl) and the like represent kazm, - v / ird es it is preferred that E is an alkyl group.

The "compounds which are prepared by aez. Process of the invention, ie the Yc II in the above-mentioned iForiael, are denoted here ax the Sanmol term" 1-hydroxyorgano-loldipiiospiiongäuren ¹ ·, and 'iieniL E a preferred i- lkylgruppe is _s werdeji these compounds generally herein as ^ i-üydroxy-aiedrigallryliden- '1.1-diphosphonic acids designated ^n. Lie YerbinditngsiL Carnies. also referred to as alkane-i-hydroxy-i-diphosphonic acid. Such compounds have proven to be suitable for inhibiting metallic metalations in other systems; see US patent specification 3 214 454- ·

To lower, aliphatic monocarboxylic acids, which in the before

Vinegar-lying invention that can be used include vinegar acid, acrylic acid, propionic acid, propiolic acid, ldo'outyric acid, Methacrylic acid, ii-3utyric acid, vinyl acetic acid, ethylnethyl acetic acid and the same. Ss will prefer to use these acids in a concentration above about 97 & 3 ^ & au, obglaicii acids with lower water levels are used can be.

BAD ORIGINAL .10-9882 / 1 9 75

Yo ii the liquid Peaktionsprodulrt formed in the process of the present invention, step (a), first the fact that laan carboxylic acid and phosphorus trihalide unsetüt is angenoiruusn, da2 it is substantially or predominantly a Cenisch of phosphoric ^ (incl. Ortho- and pyrophosphoric acids and their carbon monomers) and acylated derivatives thereof (usually in lower amounts. Honing) and, as a by-product, is organohalide (carboxylic acid bronide or chloride), ilaiogenhydric acids (IIBr or HCl), { not unconditionally containing carboxylic acid and the like A reaction product can be produced by physical, chemical, chemical reaction of the carboxylic acid and the phosphorus trihalide in a molar ratio of at least about 2: 1 (carboxylic acid ).

and preferably at least approx. 3s1, although a slight excess of carboxylic acid, such as about 10 to about 50% by weight, especially based on the weight of the reaction partners, is particularly preferred. It is preferred that the phos- | phosphorus trihalide is added to the carboxylic acid.

In the above-described rigidity (a), the reaction is carried out at • Tsniperaturen which are sufficient to keep the mixture of reaction product and the orgarohalide occurring as ITcbenproduct liquid, these Tcn-p. Kunnen vary, depending on the used carboxylic acid ur.d like -.vcrden However, in this stage GeV / ohnl.2o. .iperaturen from about 10 to about O ⁰ 3C ⁰ C AdminC-ndot wherein nä.3ige by -3-

10 9 8 8 2/197 5

about 30 ° to about 60 ° ö preferably v / erdc-n.

In making the ge \ 7ünGchten Pliosplioncäuren under Yer <~ turn other methods which run Roaktioncii oftnals exothermic and are therefore difficult to control and handle *

However, since the preferred reaction here is endothermic, and with it the advantage of better control of the procedural waste given iot, tendons can her ο Eoalrtions sites and the like according to the method of the present hearing c-rlial- ™ will be.

The liquid, previously described reaction product is then in the process step (b) described above to elevated temperatures, which im. general be in the range of about 90 ⁰ C to 18O ⁰ C, and- the like, depending on the particular reactants used and under atmospheric pressure, although sub- or superatmospheric pressures ·. can be used and are preferably heated at reflux temperatures (ie temperatures at which at least some of the reactants and / or the product form gases from the liquid reaction product). During this temperature rise, the carboxylic acid halide by-product contained in the liquid reaction product is formed as a gas from this product and is generally collected for further use.

After the by-product carboxylic acid halide gases are essentially removed, then becomes the liquid Reaction product in the reaction zone (as in the above

109882/1975 _{BAD 0R! S1NAL} ' ⁹ "

■ - 9 -

gen step (c)) However, no mention to a temperature lower than about 6O ⁰ G, to a temperature "at which the liquid product would freeze, cooled. It was" found in experiments in connection with the present invention is that at temperatures above about 60 ^° C. the rate of formation of the hydrohalide gases which are formed during the reaction is too rapid, and that at this rapid rate of formation there is a loss of reaction raw materials, for example by entrainment of acetic acid in the gases. As such, the reaction does not proceed at temperatures below about the freezing point of the liquid reaction product and reaction raw materials. The preferred cooling region in this step (c) is of about 50 to about 4O ⁰ C.

In connection with step (d) described above, up to 70% by weight, preferably from about 30 to about 65 wt. $ Based on the total weight of the Reaction in step (a) given above. Used / ended carboxylic acid, added to the cooled, liquid reaction product in the reaction zone.

In step (e) the initially cooled liquid becomes Reaction product the Eh.osp3aortrihalog.enid added. The additional carboxylic acid carried out in step (d) is located himself.- also in the Realctionssone. It is preferred that at the addition of the Fnoaphortrihalogonida to the content of the reaction zone is stirred at least sideways »in order to provide effective, additional

109882/197 5 -10-

-.10 -

to / form quantities of the liquid realization product. the Phosphorus trihalogenates added in this step (e) amount ΐ up to 70 & 3v7.-Jj, preferably from about 30 to about 65% by weight, based on the total weight of the . previous "step (a) used phosphorus trihalide. Y / in addition is the molar ratio of the carboxylic acid and des Phosphorus trihalide in steps (d) and (e) the same, as previously referred to in connection with step (a), for example at least 2/1.

With the formation of additional amounts of liquid reaction product, the contents of the reaction zone are again subjected to the above-described heating step to elevated temperature (b). This second heating stage forms the previously described stage (f) in the sequence of the sequence. This heating stage (f) is carried out at temperatures of about 90 to about 180 C either at atmospheric, subatmospheric or superatmospheric pressure. remove any additional organohalide by-product gases formed which are collected and reused as described herein. The heating of the liquid reaction product from the temperature of the "second reaction" stage, for example, 30 to 40 ⁰ C to 9O ⁰ C also leads to a certain distance of · specified Nebenproduktgäse.

While the liquid reaction product is in the reaction zone under the temperature conditions specified above

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• "" BAD ORfGi

is held, at least part of the total collected Carboxylic acid halide by-product of this liquid Product returned or recycled. This process forms stage (g). Although the halide by-product can be fed as grass, it is preferably obtained as a liquid (because it is preserved as a liquid phase is easier to handle and allows better control of the reaction), to the liquid part of the Product and preferably under the exposed surface ' of the product (under the surface layer), that is, under the surface from which vapors are generated during heating is added. Although one has some advantages the practice of the present invention can be achieved by the fact that the halide by-product is formed Adding vapor from the liquid part during the heating will use this method because of the possibility of higher losses of the halide by-product from the reaction vessel is not preferred. Although all of the J acid halide (bromide or chloride) by-product, such as previously described, can be fed back to the reaction product during step (g), this is not preferred because such amount is generally in excess of that for attaining the benefits of the present Invention required amount, which, broadly speaking, the handling of unnecessary amounts of halide by-product would result. Furthermore, although extremely low amounts of the halide by-product are added to the ·

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Reaction product during step (g) to achieve a certain degree of improvement or advantages according to the present invention, may be added, preferably, amounts (on a weight basis) of about 10 to about 50 $ of the (jesame halide by-product phase, the are formed during heating steps (b) and (f) described above. Any amounts of halide by-product that are not "used as recycled or recycled halide-tekenene product can be hydrolyzed to carboxylic acid and again to carboxylic acid by known methods Reuse as a reactant in the production of the liquid reaction product.

A normally solid, for example a solid mass at room temperature of about 25 C, forming an anhydrous reaction product is in this stage (g) by "the preceding "circuit" of the halide byproduct described, usually in addition to a portion of the desired Product (i-hydroxy-organo-1oi-diphosphonic acids) or derivatives, contains a complex mixture of products believed to be condensed or dehydrated species, such as polymers, of the desired product and, in some cases, excess or not converted carboxylic acid halide by-product is. Ss' it should be pointed out that it is not intended to defeat the invention by the considerations given above and / or

limit theoretical discussions. -13 - JAHSiSC ^ Q 9 8 8 2/1975

SAD ORIGINAL

In stage (h), the desired 1-hydroxy-organol. 1-diphosphonic acids can be obtained from the normally used functions. anhydrous reaction product can be obtained by many and varied known methods. This includes an alcohol treatment according to Canadian patent specification 720 189 and a water and / or steam treatment according to Canadian patent specification 701 850, to which reference is expressly made here. However, it is preferred to obtain the desired l-hydro; -: y-organo-II-diphosphonic acids from the normally solid reaction product by means of steam treatment. The anhydrous reaction product may be steamed v / ground while at elevated temperature s, that is above 100 ⁰ C and preferably from about 115 ⁰ C to about 15O ⁰ C and under atmospheric pressure (although under atmospheric and atmospheric over-pressure can) kept v / ird, whereby both carboxylic acids, if present, can be evaporated γ / earth, which can be used for reuse as starting material, as well as any of the condensed or dehydrated types of the desired product, if such present 3ind, be hydrated. This steam treatment stage provides an aqueous, usually highly concentrated, (preferably higher than about 50% by weight) solution or slurry of the desired product

• 109882/1975

BAD ORfGINAt

se, that steam preferably from about 110 to about 150 ⁰ C, initiates at a! temperature of about 100 to about 20O ⁰ C,! in the anhydrous product in a .solchen manner or introduces that intimate contact de3 anhydrous product with the steam is formed, for example by steam blowing or the like. -

Depending, inter alia, on the reactants used, the reaction conditions used and the amount of recycled carboxylic acid halide byproduct to the liquid ^:. In some cases (preferably in the anaata process described below) it may be necessary to add water to the normally solid, anhydrous reaction product before obtaining the crushed product from the normally solid, anhydrous reaction product. The amount of water that can be added can vary, but is usually in an amount which substantially subsides or ceases the exothermic reaction of the anhydrous product (due to the addition of the water). Such amount will usually range from about 1 to about 40 weight percent based on the weight of the anhydrous product, and preferably from about 10 to about 20 weight percent.

The l-hydroxy-organo-l.l-diphosphonic acids that normally Solid materials can be removed from the aqueous medium, though , desired, tron as crystals by various methods

109882/197 5 _GÄD original-15-

become non, v / ie example cr / cioe by removing the water by evaporation including Valaiunverdanisierung, by Slri-

Allowing the connections to stabilize by cooling at relatively hot saturated aqueous solutions, by letting the compounds crystallize from a saturated solution by means of. Inoculate the solution by precipitationχ by adding a nixable Solvent in which the compounds are more soluble are, νά <3 methanol, jithanol, acetone and the like. Usually l: Open the anorphic forms of the compounds formed when the solution water quickly under high temperature conditions, like by quick drying, drum drying and the like, is aborted.

The reaction can be carried out by many and varied methods. For example, in an approach or gradual charging process the low aliphatic Monocarboxylic acid reactants a suitable. Reaction vessel are supplied, which is equipped with a stirrer is, and the phosphorus trihalide is either continuous. or discontinuously to the carboxylic acid with stirring and preferably below its surface, in order to avoid losses of the phosphorus Avoid trihalide reactants added. Thereafter, the reactants can moderate to the formation of the liquid Reaction product and. then continue to elevated temperatures to remove the organohalide by-product heated from the reaction vessel. As a result of the aforementioned heating stage in the reaction

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'^' ^ö BAD ORIGINAL

additional space freed up in the vessel, additional reactants are introduced after the contents of the vessel have been cooled, and then another heating step is carried out to remove more organohalide gases. The organohalide by-product can then be returned to the reaction vessel during the final heating step, that is after all of the by-product gases are distilled off, and thereafter the product can be steamed to remove the to obtain the desired i-hydroxy-organo-1 »1-diphosphonic acid.

Another process available for use is a continuous process in which the reactants are continuously transferred to suitable reaction vessels, both with the feed rate of the reactants and other reaction conditions, such as the temperature, be fed, the process being used to continuously withdraw the desired product. This can be achieved by using, for example, a series of four reaction vessels in which the liquid reaction product is prepared in a first vessel, then fed to a second reaction vessel, in from which the organohalide by-product is distilled off, adding further amounts of reactants to the contents of the reaction vessel after cooling, then adding the by-product gas again distilled off and then the remaining liquid product is fed to a third reaction vessel and under increased Temperature conditions heated while going to this

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Vessel at least a portion of the total organohalide by-product, which was distilled off in the second reaction vessel, is added again to produce a normally solid, To form anhydrous reaction product and that then, the product is fed to a fourth reaction vessel in which the steam treatment can be carried out. The residence times in each reaction vessel can be coordinated so that that they are approximately the same, that is to say that, for example, in each reaction vessel a residence time of is maintained for about 30 to 120 minutes, so that one pass of the reactants is relatively continuous in the reaction and a discharge of the desired product

The following examples serve to illustrate the invention, parts being based on weight, unless because that this is stated otherwise.

example 1

A charge of approximately 210 g (3t 5 mol) of glacial acetic acid is placed in a 500 ml reaction vessel equipped with a heat transfer jacket and heated ^{to approximately 38 ° C.} Approximately 137 g (1 mole _t 0) pol are added with stirring for about 30 minutes while the temperature is maintained by heating to about 35 ° C. The liquid reaction product formed is heated to a temperature of approximately 100 to 105 ° C., during which temperature rise approximately 160 g of the acetyl-109882/197 5 ~ ¹⁸ ~

chloride by-product and small amounts of HCl (approximately 20 g) and acetic acid (approximately 15 g) are distilled off and collected. This simultaneous heating and destruction stage takes about 25 minutes. The liquid remaining in the reactor product is then cooled to 3O ⁰ C, to which one tap water runs about 10 minutes through the heat transfer jacket. About 105 grams (1.75 moles) of glacial acetic acid are then added all at once to the cooled liquid reaction product. To this mixture of liquid reaction product and glacial acetic acid, 69 g (0.5 mol) of PCI are added over about 7 minutes, while the total content of the reaction vessel is kept at 50-35 ° C. The acetyl chloride by-product is then distilled off for about 21 minutes until the entire contents of the reaction vessel reach a temperature of about 109.degree. About 40 grams of the acetyl chloride distillate is added below the surface of the reaction product over about 30 minutes while maintaining the reaction mixture at a temperature of about 110-115 ° C. to form a normally solid, anhydrous reaction product. The desired product 1-hydroxy-ethylidene-II-diphosphonic acid (HEDP) is obtained from the anhydrous reaction product, to which about 30 g of water are added over 30 minutes to the batch at such a rate that the exothermic reaction can be controlled in such a way that the approach at about 110 -

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10 9 8 8 2/1975

115 O is held. Then you start to blow through the steam and continue this for about 60 minutes while the batch is heated to about 155-140 °. The desired product, containing about 38 G ew .- $ water, provides about 99 "6 ° / o, based on phosphorus and contains about 0.4 fi phosphorous acid. This gives 253 g of a 61.1% strength by weight solution of HEDP which contains only 0.96% by weight of H ₃ PO ₅ . The yield is approximately 99-5 ° / ° HEDP, based on PGI _30. The production rate is approximately 253 g per 213 minutes or 1.096 g / min.

Example 1 of U.S. Patent 3,449,409 is detailed (with similar times for each stage compared to the times of the corresponding stages of the above procedure) for Repeatedly for comparison purposes. With this »repetition, a production speed of 155 g is achieved with a 61% by weight solution of HEDP per 175 minutes or 0.885 g / min "

The present inventive method, as described in Example 1, provides a 23 »9 $ increase in Production speed versus process speed, obtained by repeating Example 1 of TJS Patent 3,449,409. There will therefore be advantages of the present invention is clearly demonstrated.

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ORJÖINAL INSPECTED

' Example 2

Examples HI ₁ IV and Y of US Pat. No. 3,449,409 are repeated in detail and the production speeds are noted. Then these Examples III, IY and V are repeated again except that the improvement steps of the processes of the present invention are carried out in addition to those examples given in the examples of US Pat. No. 3,449,409 added Fe reactants 50 wt .- $ of the starting weight of the reactants used),

The production rates of the processes of these examples using the processes of the present invention are 21, 26 and 24 °, respectively, higher than the production rates of the processes of the examples as such.

Example 5

The preceding Example 2 is repeated twice, with the only exception that they used the second time Reactants 40 or 60 & ew .- ^ of the starting weight the reactants used. Essentially the same significant results will be increased Production speeds determined as they are given in 'the previous example 2',

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109882/1975

In connection with the present invention has also been found that a monocarboxylic acid anhydride instead of the may be used organo-halide by-product, if the by-product of the reaction zone is recycled for reaction with the contents therein contained and subsequent formation of the desired product HEDP _e · There was found that the monocarboxylic anhydrides which are effective in replacing the organo halide by-product are acetic and propionic anhydrides. This subject matter of the present invention is explained in detail in the following example

Example 4

Example 1 above is repeated with the exception that 40 g of acetic anhydride instead of 40 g of acetyl chloride be used. The result of this repetition of Example 1 is essentially the same as the results obtained in the previous example 1

Patent claims:

-22-109882 / 1975

Claims (9)

Patent claims c h e ί Process for the preparation of a 1-hydroxy-organo-l.l-diphosphonic acid, characterized in that one 1) at a temperature of about 10 "to about 8O ⁰ C in a reaction zone, an unsubstituted, lower, aliphatic monocarboxylic acid and a phosphorus trihalide, namely phosphorus tribromide and / or phosphorus trichloride in a molar ratio of at least about 2 liters to form a liquid reaction product implements, 2) the liquid product is heated in the reaction zone to temperatures of from about 90 to about 180 ° during the organo-halide by-product is removed as a gas from the reaction zone, the organo-halide is collected for the use specified below, 3) the liquid product at a temperature from about the freezing temperature of the liquid product to about $ 0 ° C cools and maintains this temperature, 4) to the cooled, liquid product in the reaction zone up to 70% by weight »an unsubstituted, lower,
aliphatic monocarboxylic acid, based on the total weight, of the Hono- carboxylic acid, adds -23- 10 9 8 8 2/1975 5) to the chilled, liquid product and the additional Monocarboxylic acid, both in the reaction zone, up to 70% by weight of phosphorus trihalide, based on the total weight of the phosphorus trihalide initially present in stage 1 with the caveat that the molar ratio of acid added to trihalide at least 2: 1 is with the formation of further liquid product, 6) all the liquid product and the phosphoric acids- I phase in the reaction zone is allowed to stand for a sufficient time to essentially convert it into a liquid phosphoric acid phase and a liquid by-product organo-halide phase to separate and separate the liquid phases, 7) the phosphoric acid phase heated to temperatures of about 90 to about 180 ^{0 G,} 8) at least a portion of the organic halide by-product of the reaction zone supplies again to give the organohalide by-product is added to the door * at the indicated temperature held liquid product, whereby a normally solid, water-free reaction product is formed, and thereafter 9) 1-Hydroxy-organo-l.l-Diphosphonic acid from the anhydrous Product wins. 109882/19 75 2. The method according to claim 1 characterized ge Ic ο n η a eic Ια η et that the percentage of Ilono carboxylic acid and the phosphorus trihalide, which in stages 4) bzTT. 5) added is from about 30 to about 65 * - #. 3. The method 'according to claim T geke η η ζ eich η et that the 1-hydroxy-organo-1 _: «1-dipho & phonic acid is an i-hydroxy-lower alkylidene-it-di-. phosphonic acid and the lower aliphatic lionocarboxylic acid used is a liiedrigalkylntonocarboxylic acid. 4 «The method according to claim 3, since, g e k e η η - · shows that the 1-hydroxy-organo-t.T-aiphosphonic acid formed 1-hydroxyethylidene-1 · 1-dipho-sphonic acid, the ver \ 7: te liiedrigalkylmonocarbonsäure acetic acid and the phosphorus trihalide used is phosphorus trichloride. ψ 5. · The method according to claim 1 characterized geke η η ζ eich η et that the 1-hydroxy ~ organo-1,1-diphosphonic acid is obtained from the normally solid product by steam treatment. 6 «method according to claim 5, thereby g e k e η nz ei c h η e t that one loves the organochloride product 109882/197 5 ~ ²⁵ "* the reaction zone in the range of about 10 to about 50 wt. ^c / o, based on the total amount of the organic chloride by-product removed from the reaction zone, and added as a liquid below the surface of the liquid product. . ■. 7. Ancestor on the right to claim. 6 characterized that dip low aliphatic conocarboxylic acid and the PIio3phortrihalogenid in stage 1) and in stage 5) in an unosilolar ratio of at least about 3: 1 and in Stage 1) at temperatures from about 30 to about 60 ° C reacted to form a liquid reaction product That the Danpfbehandlung of the anhydrous product is carried out while maintaining the anhydrous product at einer'Temperatur of about 115 to about 15O ⁰ C, 8 · Verfahren.gemäß claim 7 is characterized labeled in, · 9. The method genäß claim 1 thereby marked records that the 1-hydroxy-organo-rl.l produced Diphosphonic acid is 1-hydroxypropylidene-l-diphosphonic acid and the used lower aliphatic ilonocarboxylic acid propionic acid is· ' -26-109882 / 1975 .10 .. The method according to claim 1, characterized that in stage 3 a monocarboxylic anhydride, namely, acetic anhydride and / or propionic anhydride are used in place of the organo-halide by-product will. · · · - 109882/1975