DE2132025A1 - Process for the production of phosphonic acids - Google Patents

Description

DR. BERG DIPL.-lNG. STAPF

PATENTANWÄLTE 8 MÜNCHEN 8O, MAUERKIRCHERSTR. 45

9 1 ^ 9 Π 9 R

Dr .. Berg Dipl.-Ing. Stopf, 8 Manchen 80, Mauerkircherstraße 45

Your sign

Your writing

Our sign

date

June 28, 1971

Lawyer s cürb e 21 14 % Be / Ho

Monsanto Gonrpany 8t. Louis / USA

"Process for the production of phosphonic acids"

The present xirfindun ^ relates to processes for the preparation of phosphonic acids and ii: i in particular an improved process: iur Hox'ütollung of l-IIydroxy-organo-ll-DipiioijplionsLlu-L'du , in particular the l-IIydroxy-lower alkylideii-ll-Diphoi .3-pjiona; i.urüii, v / obei es for continuous working v / eiae

μ _f -., 10988 3/1959 0ADORlGiNAt

* »70 43 (» 70 43) 4 «33 10 (M 33 1 ·) TeUoramm«! IEROSTAPFPATINT MtMttfl TELEX 05 24 Κβ BERG Bank. faywMtt VtrtiMlNmk M «mImm 4M 10» Peit »*« ki MMmI 4 * 4 ·

suitable is.

According to TJ ₀ S. patent specification 5-449 409, 1-hydroxyorgano-1 _o 1-diphosphonic acids can advantageously be prepared by reacting a lower, aliphatic monocarboxylic acid and a phosphorus trihalide (phosphorus tribromide or phosphorus trichloride) according to such a reaction sequence, that at least a portion of the organohalide (bromide or chloride) by-product from the reaction is used as a reactant for the preparation of the desired phosphonic acids. Many and varied advantages are achieved in the teachings of this patent, including the production of certain diphosphonic acids in high yield, e.g., greater than approx. 97 $ and purity, such as with a lower ■ salary than approx. 3 $ H ^ PO, belong. In this patent it is further stated that the “process described there uses at least part of the organohalide by-product that would otherwise be classified as a waste product, and that the process can be controlled easily and selectively.

While the process described in US Pat. No. 3,449,409 has many advantages, it is an engineering process according to the production quantity or according to the manufacture of the desired. To evaluate the end product per unit of time any improvement is within the scope of these guidelines mentioned very desirable, especially if these do not require additional capital investments to achieve the

-3-

109883/1959

v / ünselite final result au «

3s is. Accordingly, a major contradiction was bound by the present hearing. an improved process for the preparation of 1-hydroxy-orgaiio-l-diphosjxhonsäuren to provide.

Further 3 objects of the present invention are:

- üin process for the production of l-hydroxy-organo-lol-Dipliosphoiisöuren, da.s is suitable for a continuous working method.

- A process for the production of l-hydroxy-organo-l-dipliosplioiisuuren, This is an increased production, measured by the amount of 3 Loire produced per unit of time, in comparison to processes according to the state of the art.

Basically, the method of the present invention consists in (a) converting a lower aliphatic Llonocai'bonsäure and a phosphorus trihalide (Phosphoi ^ tribromide or phosphorus trichloride) in a reaction zone to form a liquid reaction product, (b) the reaction product is sufficiently long can, in essence, the ura L'SEPARATION in a f ₇ HiSSIgC acid of phosphorus-containing phase luid a liquid ITebeiiprodukt-organo-halide phase and the separation 2u reach the "two liquid phases, (c) the flüsoige _/ acid of phosphorus-containing phase lcühlt and at a lower temperature than about 60 ° h

109883/1959

ßAÖ ORIGINAL

chilled, liquid. Acid of phosphorus-containing phase, hereinafter referred to ^{for the} sake of simplicity, phosphoric acids (f -phase, in the reaction zone up to 70% by weight <> $ of a monocarboxylic acid (as defined above and below), based on the total weight of the in step (a ) converted starting monocarboxylic acid, adds (e) to the cooled, liquid phosphoric acid phase and the additional monocarboxylic acid, both in the

k reaction zone, up to 70 G ew _e # phosphorus (as defined above), "adding inscribed on the total weight of the Anfangsphosphortrihalogenids in the preceding stage (a) with the proviso that the molar ratio of the acid supplied to the supplied trihalide at least 2: 1 is, with the formation of a further liquid (reaction) product, (f) the standing and separation process of the previous step (b) is repeated, (g) the entire liquid phosphoric acid phase in the reaction zone is heated to elevated temperatures, (h) at least one Part of the total (collected)

ψ recirculates liquid organohalide by-product phase of the reaction zone for reaction with the liquid phosphoric acid phase, whereby a normally solid, anhydrous reaction product is formed and (i) then the desired product of a 1-hydroxyorgano-i «1-diphosphonic acid is obtained from the normally solid, anhydrous reaction product O

In connection with the process described above, there are the specific improvements over that in the US patent 3 449 410 in the procedures described above in the

^ t'G) to (f). It was _like unerwartöfectgeatellt 1Ö9883 / 19B9 ^{= '5}

that using these improvement levels (c) to (f) the production amount of the desired diphosphonic acid per unit of time is increased substantially, for example up to 40 ^, without the need for additional capital investments.

The above-mentioned increase in production per unit of time, the results from the improvements of the present invention over the methods of U.S. Patent 3,449,409 completely unexpected because it was expected that side reactions would occur if the other proportions or amounts of Phosphorbrihalogeiiid and molocarboxylic acid are added to the acid of phosphorus-containing liquid phase, the contains a large number of compounds described below, which is generally very reactive as such Mat e ri:.,! 1 en - s i-nd.

In addition, the phosphorus trihalide-LIonocarbonsuureroaktion aoi:; t the subsequent action sequence contributes to the overall reaction Use of phosphorus trichloride as a phosphorus trihalide component and stoohionietric quantities of the reaction

0 0 Ii 0

HO. "« "OH

il

PCI * + 3 R-Ci-OH _f POP + Organo- «lilorid-

ι ^ ^x oil Ileben product

OH - ■■ - -

_4ηΛ . BATH ORIGINAL

109883/1959

wherein the radical R is an aliphatic group with 1 to about 6 carbon atoms is “Although the remainder R is unsaturated hydro carbyl groups, such as ethylenically unsaturated hydrocarbyl groups (Alkenyl) and the like, it is preferred that R is an alkyl group.

The compounds that can be prepared by the process of the present invention, i.e., the compounds II in the above formula are referred to here with the collective term "1-hydroxyorgano-1eidiphosphonic acids", and when R is a preferred alkyl group, these compounds are referred to herein generally as "1-hydroxy-lower alkylidene-1 oi-diphosphonic acids "denotes ,, the compounds can also referred to as alkane-1-hydroxy-1,1-diphosphonic acids will. Such compounds have proven to be suitable as sequestering agents for heavy metal cations in aqueous systems proven; see U.S. Patent 3,214,454.

Lower aliphatic monocarboxylic acids that can be used in the present invention include acetic acid, acrylic acid, propionic acid, propiolic acid, isobutyric acid, methacrylic acid, N-butyric acid, vinyl acetic acid, ethylmethyl acetic acid, and the like. It is preferred to use these acids in a concentration above about 97 Grew _e #, although acids with lesser amounts of water can be used.

Γ0 98 83/1 959 - '

From the liquid reaction product used in the process of the present invention, step (a), is first formed by adding carboxylic acid and phosphorus trihalide implements it is believed to be

a mixture of phosphoric acids (including orthO'- and pyrophosphoric acids and their mixtures) and acylated derivatives thereof (usually in minor amounts) and as a by-product organohalide (carboxylic acid bromide or -chloride), hydrohalic acids (HBr or HCl), unreacted carboxylic acid and the like contains »This reaction product can be produced by physical mixing, including chemical reaction of the carboxylic acid and of phosphorus trihalide in a molar ratio of least about 2: 1 (carboxylic acid: PX ^, where X is the halogen atom is) and preferably at least approx. 3: 1, although a slight excess of carboxylic acid, such as about 10 to approx. 50 Gewo $, based on the weight of the reactants is particularly preferred. It is preferred that the phosphorus trihalide be added to the carboxylic acid

In step (a) described above, the reaction is carried out at temperatures which are sufficient for the mixture aiis reaction product and that occurring as a by-product To keep organohalide liquid, this temp. Can vary, depending on the one used. Carboxylic acid and Like. However, temperatures of about 10 C to about 80 C used, with moderate Temperatures from -8-

109.88 3 / .195 9

are preferably about 30 ° to about 60 ⁰ O.

In making the desired phosphonic acids using other processes, the reactions are often exothermic and are therefore difficult to control and handle. However, since the preferred reaction here is endothermic and so the benefit of better control of process conditions is given, faster response times and the like can be obtained by the method of the present invention.

will be

The liquid reaction product can then be separated into two phases, which are assumed to consist essentially or predominantly of a phosphoric acid phase and the content of acylated derivatives thereof and of a Qr ganohalide by-product phase, see step (b) above. When using phosphorus trichloride as the reactant, the phosphoric acid phase is the bottom layer and the organochloride by-product phase is the top layer. When phosphorus tribromide is used as the reactant, the phosphoric acid phase is the top layer and the organobromide phase is the bottom layer. These liquid phases are easily formed from the liquid reaction product, although the boundaries between such layers are not necessarily clear if the liquid reaction product is left to stand for a short time, preferably motionless (but usually times longer than about 30 minutes, for example about 30 minutes) Minutes to 24-0 minutes

^det) * 109883/195 9 " ⁹ "

- y _

The liquid layers can be easily separated by various methods such as decantation, centrifugation and the like. Pilter aids can be used, if desired, such as coalescing filters and the like to achieve better separation of the "two layers. After the liquid organohaligenide by-product, for example the liquid carboxylic acid halide by-product, is separated or substantially removed from the reaction zone , remaining in the reaction zone liquid phosphoric acid phase is then (as indicated above in step (c)) to a temperature lower than about 6O ⁰ C, but not cooled to a temperature at which the liquid acid phase would freeze. It was during of the experiments relating to the present invention found that at temperatures above 60 ^° C., such as 80 ^° C., the formation of hydrogen chloride gases which are formed during the second reaction (see steps (d) and (e) above) takes place too quickly so that this rapid rate of formation results in a loss of reaction raw material, e.g. by vinegar entrainment acid in the gases. As such, the "second" reaction does not proceed at temperatures below about the freezing point of the liquid phosphoric acid and reaction raw materials. A temperature of approximately 30 to approximately 4-O ⁰ C is therefore preferred as the cooling range in this stage (c).

109883/1959 -10-

In connection with step (d) described above, up to 70 percent by weight, preferably from about 30 to about 65 percent by weight, based on the total weight of the reaction in step (a) given above, are used Carboxylic acid is added to the cooled liquid phosphoric acid phase in the reaction zone.

In step (e) the initially cooled liquid becomes Phosphoric acid phase added the phosphorus trihalide. the Additional carboxylic acid fed in in step (d) is also in the reaction zone. It is preferred that at the addition of the phosphorus trihalide, the contents of the reaction zone is stirred at least intermittently in order to achieve effective, additional To form quantities of the liquid reaction product. The amount of phosphorus trihalide added in this step (e) is up to 70% by weight, preferably from about 30 to about 65 Gewo - $ based on the total weight of the previous step (a) used phosphorus trihalide. Furthermore, the molar ratio of the carboxylic acid and des Phosphorus trihalide in steps (d) and (e) is the same as previously referred to in connection with step (a) was, for example, at least ■ 2: 1.

With the formation of additional amounts of reaction product the contents of the reaction zone are again subjected to the above-described standstill and separation stage (b). This second

χ liquid -11-

109883/1959

Standstill and isolation level "forms in the sequence of the sequence stage (f) as previously described. This again results in the formation of 2 phases, i.e. the Plio s phoric acid phase and the organo-halide by-product phase, the last-mentioned phase being separated from the first-mentioned phase.

The phosphorus: lurenphaseprodukt \, previously described, is then (in the above step (g)) at an elevated temperature, which are generally in the range of about 90 to about 18O ⁰ C, depending on the particular reactants used and the like, and under atmospheric Pressure, although both below and above atmospheric pressures can be used and preferably to reflux temperatures (ie, temperatures at which at least a portion of the reactants and / or the product form gases from the phosphoric acid product).

While the phosphoric acid product is maintained at elevated temperatures, at least a portion of the carboxylic acid halide byproduct becomes returned to this product or recycled. This gives level (h). Although the halide by-product can be supplied as a gas, it is preferably supplied as a liquid (because it is considered a liquid Phase is obtained, is easier to handle and a better one

-12-109883 / 1959

Control of the reaction allows) to the liquid portion of the product, and preferably below the exposed surface of the product (below the surface layer), d _o h. added below the surface from which vapors are generated during heating. Although some advantages can be obtained in practicing the present invention by adding the halide by-product to the vapor formed from the liquid portion during heating, this method is not preferred because of the possibility of greater losses of the halide by-product from the reaction vessel. While all of the collected carboxylic acid halide by-product, as previously described, can be recycled to the reaction product during heating, this is not preferred because such amount is generally in excess of that required to achieve the benefits of the present invention which, generally speaking, would result in the handling of unnecessary amounts of halide by-product. Moreover, although extremely low amounts of the halide by-product can be added to the reaction product during heating to achieve some degree of improvement or benefit in accordance with the present invention, it is preferred amounts (on a weight basis) of from about 10 to about 70 ° >, about 20 to about 60 % of the total halide by-product phase, which is separated from the phosphoric acid phase, as described above, in steps (b) and (f) is particularly preferred.

-13- 10 9883/1959

has been separated. Any amounts of halide by-product, which cannot be used as recycled or recycled halide by-product hydrolysed to carboxylic acid by known processes and reused as a reactant in the production process of the liquid reaction product used in the cycle will.

A normally solid, for example a solid mass at room temperature of approximately 25 ⁰ C forming, anhydrous reaction product is obtained through the heating stage described above

(h), which is usually in addition to part of the desired product (1-hydroxy-organo-l.l-diphosphonic acids) or derivatives containing a complex mixture of products of which are believed to be condensed or dehydrated species such as polymers of the desired product and in some cases excess or unreacted organo-halqgeaid-E by-product. It should be pointed out that it is not intended to enhance the invention by the preceding considerations and / or theoretical discussions to restrict.

The desired 1-hydroxy-organo-1,1-diphosphonic acids can be used in stage (i) from the normally solid, anhydrous reaction product according to many and various known Procedure can be obtained. This includes an alcohol

-U-10 9883/1959

heat treatment according to Canadian patent specification 728 189 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 truncated 1-hydroxy-οrgano-II-diphosphonic acids from the normally solid reaction product by means of steam treatment. The anhydrous reaction product can be treated with steam while it at elevated temperatures, that is "held above 100 ⁰ C and (can be used although under atmospheric and about atmospheric pressures), preferably from about 115 ⁰ C to about 15O ⁰ C and under atmospheric pressure whereby both carboxylic acid, if any, can be evaporated, which can be used as starting material for reuse, and any of the condensed or dehydrated types of the desired product, if any, are hydrated. This steaming step provides an aqueous, usually highly concentrated, (preferably higher than about 50 (xeWo / 6%) solution or slurry of the desired product Temperature of about 100 to about 200 ⁰ C, preferably from about 110 to about 150 ⁰ C, introduces or introduces into the anhydrous product in such a way that an intimate contact of the anhydrous product with the steam, for example by steam -

-15-109883 / 1959

blow through or the like is formed.

Depending, among other things, on the reactants used, the reaction conditions used and the amount returned Carboxylic acid halide by-product to the phosphoric acid It may be necessary in some cases, preferably with the preparation process described below V / ater to the normally solid, anhydrous reaction product prior to recovery of the desired product add from the normally solid, anhydrous reaction product. The amount of water that can be added can vary, but is usually in an amount sufficient to counteract the exothermic reaction of the anhydrous product (due to the addition of of the water) essentially subsides or stops. Such an amount is usually in the range of about 1 to about 40 wt .- $ based on the weight of the anhydrous product and preferably from about 10 to about 20 wt .- ^.

The 1-hydroxy-organo-l.l-diphosphonic acids, which normally Solid materials can, if desired, be recovered from the aqueous medium as crystals by various methods such as by removing the water by evaporation including vacuum evaporation, by allowing it to crystallize of the compounds by cooling with relatively hot saturated, aqueous solutions, by crystallizing

-16- 1 09883/1959

let the compounds out of a saturated solution by inoculating the solution, by precipitation by adding a miscible Solvent in which the compounds are less soluble, such as methanol, ethanol, acetone and the like. Usually, the amorphous forms of the compounds can be formed when the solution water rapidly under high temperature conditions, such as by rapid drying, drum drying and the like, is driven off.

The reaction can be, by many and different processes be performed. For example, in a batch or staged feed process, the lower aliphatisas Monocarboxylic acid reactants are fed to a suitable reaction vessel equipped with a stirrer and the phosphorus trihalide is either continuously or discontinuously to the carboxylic acid with stirring and preferably under the surface to avoid losses of the phosphorus trihalide reactant to avoid and added at moderate temperatures to the liquid reaction product form. The reaction mixture is then allowed to separate into 2 rather different layers or phases, the 2 “B. durct Removing the organo-halide 'separated from the reaction vessel will. In the space in the reaction vessel that has become free as a result of the separation step described above additional reactants are introduced after cooling the contents of the vessel and then another standstill and

109883/1959 ~ ¹⁷ ~

Separation step carried out in order to remove further liquid organohalide by-product. Part of the organohalide by-product can then be fed back into the reaction vessel during the final heating stage, ie after the newly formed by-product has been removed and the phosphoric acid phase has been heated, and then the product can be steam-treated to obtain the desired 1-hydroxy-organo-1.1- Obtain diphosphonic acid. ■ i

Another for use available method is a continuous process in which the reactant is continuously in suitable reaction vessels, so-■ well supplied with the feed rate of the reactants and other reaction conditions such as the temperature v / earth, v / obei the method is used to continuously withdraw the desired product. This can be achieved by, for example, a row of four _t

Reaction vessels are used in which the liquid reac- * tion product produces in a first vessel, this is then fed to a second reaction vessel, in which the organohalide by-product after allowing to stand, larger amounts of reactants are separated from the contents of the reaction vessel after cooling admits, then again separated after standing and then the remaining, liquid phosphoric acid phase one third reaction vessel and under increased temperature conditions heated while going to this vessel at least

-18- 109883/1959

a portion of the total organo halide by-product found in removed from the second reaction vessel to add a normally solid, anhydrous reaction product form, and that the product is then fed to a fourth reaction vessel in which the steam treatment is carried out can. The residence times in each reaction vessel can be coordinated that they are approximately the same, i.e. that, for example, each reaction vessel has a residence time of approximately 30 to 90 or even 120 minutes is maintained, so that one pass through the reactants in the reaction and a discharge of the desired product relatively continuously receives.

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 about 210 g (3.5 mol) of glacial acetic acid in a 500 ml reaction vessel equipped with a heat transfer el smant is equipped introduced and heated to about 38 ⁰ C. Approximately 137 g (1.0 mol) of PCl 3 are added with stirring for about 30 minutes while the temperature is maintained by heating at about 34 ⁰ C. The liquid reaction product formed is allowed to stand for about 35 minutes to separate it into 2 layers, a phosphor

-19- 109883/1959

acid phase void a chloride by-product phase that is physically separated. The liquid remaining in the reaction vessel phosphoric acid phase is then cooled to 3O ⁰ C characterized in that tap water by the V / ärmeübertragungsmantel runs approximately 3 minutes. Recirculated 105 g (1.75 mol) of acetic acid are then added all at once to the cooled, liquid phosphoric acid phase (product). To this mixture of liquid phosphoric acid product and glacial acetic acid, 69 g (0.5 mol) of PCI3 are then added over approximately 8 minutes, while the total contents of the reaction vessel are kept at 30 ° C. After standing, the newly formed liquid reaction product divides into the 2 phases mentioned above. The by-product phase is then separated from the acid phase which remains in the reaction vessel. The total acid phase is heated for about 15 minutes until the total content of the reaction vessel a temperature of about 106 ⁰ C is reached. About 87 grams of chloride by-product are then added below the surface of the reaction product over a period of about 30 minutes, during which time the reaction mixture is maintained at a temperature of 110 to 115 ^° C to form a normally solid, anhydrous reaction product. The desired product 1-hydroxy-ethylidene-II-diphosphonic acid (HÄDP) is obtained from the anhydrous reaction product, to which 40 g of water are added to the batch over 30 minutes at such a rate that the exothermic reaction of the batch at un-

-20-

109883/1959

danger 110 - 115 ⁰ C can be controlled. Then starting the Dampfdurefrblasen "and this continues for about 60 minutes while the batch to about 135 -. Is heated 14O ⁰ O The desired product, .- containing about 39 wt ^ of water, about 99» 5 is based on phosphorus i ° and about 0.5 ° i phosphorus acid strength is obtained from 234 g of an aqueous solution of HÄDP that only 0.95 wt, -. containing $ H3PO3 the yield is about 99 »$ 5 HA'DP based on PCl ^.. The production speed is approximately 234 grams per 226 minutes or 1.036 grams per minute.

Example 1 of U.S. Patent 3,449,410 is detailed (with similar times for each stage compared to the times for the corresponding process stages given above) for comparison purposes. One obtains with this Compare a production speed of 155 g one aqueous solution of HÄDP per 185 minutes or 0.838 g / minute «

The present process according to the invention, as in the example 1 provides a $ 23.6 increase in Production speed versus process speed, obtained by repeating Example 1 of U.S. Patent 3,449,410. Bs will thus be the benefits of the method according to the invention made clear.

1098 8 3/1959

Example 2

Examples III, IV and Y of U.S. Patent 3,449,410 are repeated in detail and the production speeds established. Then these Examples III, IY and V are repeated again with the exception that the improvement levels of the present invention in addition to the steps of the US patent given in the examples 3,449,410 were carried out. (In the improvement levels the reactants added the second time were 50% by weight of the initial weight of the reactants).

The production rates of the processes of these examples using the present inventive process are 20, 25 and 24 $ higher than the production rates of the processes of the examples as such.

Example 5

Example 2 was repeated twice with the only exception that the reactants used the second time 40 and 60 wt .- # of the initial weight of the reactants used. There were essentially the same significant ones Results at increased production speeds as noted in Example 2 above.

In connection with the conversion of the phosphoric acid phase to the desired end product, it has been found that a monocarboxylic anhydride such as acetic anhydride and propionic acid anhydride instead of the recycled organo-halogenic

109883/1959 _ ₂₂ _

By-product phase can be used. This is further explained in the following example.

Example 4

Example 1 was repeated in the same way with
the only exception that instead of the repatriation of the

Chloride by-product, approximately 87 grams of acetic anhydride were used. The result of this repetition of Example 1 using acetic anhydride in place of the chloride by-product gives essentially the same result
as obtained in Example 1.

Claims : -23-

109883/1959

Claims (9)

Claims: l ^ / Process for the preparation of a 1-hydroxy-organo-lol-diphosphonic acid, characterized in that one 1) at a temperature of about 10 to about 800C an unsubstituted lower aliphatic monocarboxylic acid and a phosphorus trihalide in a reaction zone, namely phosphorus tribromide and / or phosphorus trichloride in a molar ratio of at least about 2: 1 converted to form a liquid reaction product 2) allowing the liquid reaction product to stand for sufficient time to essentially convert it to a liquid acid Phosphorus phase (phosphoric acid phase) and a liquid organo-halide by-product phase to separate and the separate liquid phases, 3) cools and maintains the phosphoric acid phase at a temperature from approximately the freezing temperature of the phosphoric acid phase to approximately 60 ^{0 G,} 4) the cooled phosphoric acid phase in the reaction zone up to 70 wt .- ^ an unsubstituted lower aliphatic Monocarboxylic acid, based on the total weight of the monocarboxylic acid initially present in stage 1), admits 5) the cooled phosphoric acid phase and the additional monocarboxylic acid, both in the reaction zone, up to -24-109883 / 1959 70 wt .- $ phosphorus trihalide, based on the total weight, of the starting phosphorus present in stage 1) with trihalide the restriction admits that the molar ratio of the acid and trihalide added is at least 2: 1 to form another liquid product, 6) the liquid product and the Phosphor.säurenphase in the reaction zone is allowed to stand for a long enough time to be in the essentially into a liquid phosphoric acid phase and a liquid organo-halide by-product phase separate and separate the liquid phases, 7) the phosphoric acid phase to temperatures of about j 90 to about 180 ⁰ C heated, j 8) at least a portion of the organo-halide by-product phase the phosphoric acid phase, which is kept at the specified temperatures, adds, whereby a normally solid, anhydrous reaction product is formed and thereafter 9) 1-Hydroxy-organo-l.l-Diphosphonic acid from the anhydrous Product wins. 2. The method according to claim 1, characterized in that the percentage of the monocarboxylic acid and the phosphorus trihalide added in steps 4) and 5), respectively, from about 30 to about 65 Wt .- ^ is. -25-109883 / 1959 3. The method according to claim 1, characterized that the 1-hydroxy-organo-i "1-diphosphonic acid produced an i-hydroxy-lower alkylidene-id-diphosphonic acid and the lower aliphatic monocarboxylic acid used is a lower alkyl monocarboxylic acid » 4. The method according to claim 3, characterized in that the 1-hydroxy-organo-i ₀ 1-diphosphonic acid formed is 1-hydroxyethylidene-i «1-diphosphonic acid, the lower alkyl monocarboxylic acid used is acetic acid and the phosphorus trihalide used is phosphorus trichloride 5 ο method according to claim 1, characterized in that that the 1-hydroxy-organo-1 «1-diphosphonic acid from which normally solid product is obtained by steam treatment. 6 β method of claim 5 characterized in accordance that the organohalide by-product phase, the reaction zone is returned to, about 20 to about 60 G ew _e $, based on the total weight of the organic halide by-product phase which was removed from the reaction zone is, and as! liquid supplies under the surface of the liquid product. -26- 1 09883/1959 7. The method according to claim 6, characterized in that the low-aliphatic monocarboxylic acid and the phosphorus tr! halide in stage 1) and in stage 5) in a molar ratio of at least about 3: 1 and in stage 1) at temperatures from about 30 to about 60 ° C is reacted to form a liquid reaction product ο 8ο method according to claim 7 characterized in that the steam treatment of the anhydrous product is carried out while maintaining the anhydrous product at a! Temperature of about 115 to about 15O ⁰ C ο 9. The method according to claim 1, characterized in that the 1-hydroxy-organo-lol-diphosphonic acid produced l-Hydroxy-propylideii-l.l-Diphosphonic acid is and the lower aliphatic monocarboxylic acid used is propionic acid is" 10 ο method according to claim 1 characterized j that in step 4) the organo-halide by-product phase, the the phosphoric acid phase is fed back, by a monocarboxylic acid anhydride, namely by acetic anhydride and / or propionic anhydride is replaced » 109883/1959