US3624188A

US3624188A - Hypohalogenation of tetramethyl and tetraethyl methylenediphosphonates and trihydrocarbyl phosphonoacetates

Info

Publication number: US3624188A
Application number: US770805A
Authority: US
Inventors: John Downing Curry
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1968-10-25
Filing date: 1968-10-25
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30

Abstract

The process of reacting either (1) a tetraalkyl (methyl, ethyl, halomethyl or haloethyl) methylenediphosphonate or (2) a trihydrocarbyl (C2-C4) phosphonoacetate with a hypohalite in an aqueous electrolyte solution (preferably in the presence of an inert, water-immiscible, organic solvent) to produce the corresponding mono- and di-halogenated methylenediphosphonate and phosphonoacetate esters. These esters have utility as intermediates in the synthesis of detergent builders and as extreme pressure additives for lubricant compositions.

Description

United States Patent [72] Inventor John Downing Curry Oxford, Ohio [21 1 Appl. No. 770,805

[22] Filed Oct. 25, 1968 [45] Patented Nov. 30, 197 l [7 3] Assignee The Proctor & Gamble Company Cincinnati, Ohio Continuation-impart of application Ser. No; 624,226, Mar. 20, 1967, now abandoned Continuation-impart of application Ser. No. 717,999, Apr. 1, 1968, now abandoned. This application Oct. 25, 1968, Ser. No. 770,805

[ 54] HYPOHALOGENATION OF TETRAMETHYL AND TETRAETHYL METHYLENEDIPHOSPHONATES AND TRIHYDROCARBYL PHOSPHONOACETATES 10 Claims, No Drawings [52] U.S. Cl 260/986, 252/499, 260/932, 260/941, 260/969 [51] Int. Cl C07f 9/40 [50] Field of Search... 260/932, 986

[56] References Cited UNITED STATES PATENTS 3,299,123 1/1967 Fitch et a1 260/932 X 3,422,021 1/1969 Roy 260/932 X 3,471,552 10/1969 Budnick 260/932 X OTHER REFERENCES Groggins, Unit Processes ln Organic Chemistry, McGraw- Hill New York, Fifth Edition (1958), pages 206 to 208 and 250.

Bunyan et al., Journal Of The Chemical Society (London) (1962) pp. 2953 to 2958 (London) (1962) Primary Examiner-Alex Mazel Assistant ExaminerRichard L. Raymond AllorneysRichard C. Witte and Robert B. Aylor HYPOHALOGENATION F TETRAMETHYL AND TETRAETHYL METHYLENEDIPHOSPHONA'IES AND TRIHYDROCARBYL PHOSPI-IONOACETATES CROSS-REFERENCE This application is a continuation-in-part of copending U.S. applications Ser. Nos. 624,226, filed Mar. 20, 1967 and 717,999 filed Apr. 1, 1968 and both now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a process for the production of monoand dihalogenated gem-diphosphonate esters and phosphonoacetate esters. It relates specifically to a process for the production of monoand dihalogenated tetramethyl and tetraethyl methylenediphosphonates and trihydrocarbyl phosphonoacetates which are valuable intermediates in the syntheses of detergent builders and as extreme pressure additives for lubricant compositions. The use of builders as adjuncts to soap and synthetic detergents and the properties demonstrated by their use in improving detergency levels is well known. Such gem-diphosphonate esters are hereinafter and such referred to as methylenediphosphonates phosphonoacetate esters are referred to as phosphonoacetates.

The use of the halogenated methylenediphosphonates and halogenated phosphonoacetates as extreme pressure additives for lubricant compositions is disclosed in the copending application of Robert Earl Warm, Denzel Allan Nicholson and Ted Joe Logan, Ser. No. 762,966, filed Sept. 26, 1968, entitled Lubricant Composition."

Among the satisfactory builders that can be obtained from the compounds of this invention are the alkali metal, ammonium, or substituted ammonium salt forms of substituted methylenediphosphonic acid compounds derived from the halogenated methylenediphosphonate esters. The use and preparation of such salts using the compounds prepared by this invention is more fully described in U.S. Pat. No. 3,422,021 issued Jan. 14, 1969, and U.S. Pat. No. 3,404,178 issued Oct. 1, 1968. The disclosures thereof are hereby incorporated by reference. The halogenated tetramethyl and tetraethyl methylenediphosphonates produced by the process of this invention are stated, in the Roy application, to be converted to their corresponding builder salts by several methods. An example of one such preparation is the hydrolysis of tetraethyl methylenediphosphonate ester with refluxing I-ICl to produce the free phosphonic acid, and then, the addition of base such as NaOH to the acid producing the corresponding builder salt. 1

The use of salts derived from methylenediphosphonate esters as builders has not until recently been of substantial interest. Therefore, very little literature is available as to their use as builders and even lesser amounts regarding the preparation of halogenated methylenediphosphonate esters. Nevertheless, there are several methods of replacing an active hydrogen by halogenation, old in the art, by which halogenated tetramethyl and tetraethyl methylenediphosphonates might conceivably be synthesized. However, reactions such as direct halogenation of either tetramethyl or tetraethyl esters of methylenediphosphonic acid or their carbanion have proved to be limited in yield and often involve side reactions hampering the completion of the esired reaction. These reactions have been found to be impractical as they are expensive and require elevated temperatures. Such halogenation methods seldom result in yields of monoor dihalogenated methylenediphosphonate esters greater than about 25 percent.

2. Description of Prior Art The copending U.S. application, Ser. No. 587,417 of Quimby et al., filed Oct. 18, 1966, and now abandoned presents a practical process for the production of halogenated tetraalkyl methylenediphosphonates which minimizes the difficulties encountered in halogenating methylenediphosphonate esters.

This application discloses a high-yield process for the hypohalogenation of tetraalkyl methylenediphosphonates having alkyl radicals containing three to about eight carbon atoms. This process involves a two-phase reaction system comprising (a) an aqueous hypohalite solution containing electrolyte, and (b).,an immiscible methylenediphosphonate ester phase. Due to the high degree of solubility in water and aqueous electrolyte solutions of tetraaikyl methylenediphosphonates having alkyl radicals containing less than three carbon atoms, this process is not useful in halogenating these specific short alkyl chain methylenediphosphonate esters in sufficiently high yields to make it attractive. There is, therefore, a need for a process by which such methylenediphosphonate esters can be halogenated.

It has been discovered that by employing the process of this invention, satisfactory yields of halogenated methylenediphosphonates and phosphonoacetates can be obtained. This process is capable of being directed largely towards producing either the monoor dihalo derivatives of these methylenediphosphonates and phosphonoacetates. The mechanisms by which the process can be so directed will be discussed and illustrated below.

The entire scope of applicability of the invention will become apparent from the detailed description give hereinafter.

SUMMARY OF THE INVENTION It has now been discovered that halogenated methylenedisphosphonates and halogenated phosphonoacetates are prepared by a process which comprises the steps of reacting, with vigorous stirring, a compound selected from the group consisting of: (l) a methylenediphosphonate having the formula R PO Cl'l Po R in which each R is selected from the group consisting of methyl, ethyl, halomethyl and haloethyl radicals and (2) a phosphonoacetate, having the formula R 'PO CI-l C00R' wherein each R is selected from the group consisting of alkyl, alkenyl, haloalkyl, and haloalkenyl radicals containing from two to four carbon atoms, with a hypohalite ion selected from the group consisting of 0C1, OBr, and OI, the molar proportions of the reactants corresponding to one mole of said methylenediphosphonate or phosphonoacetate to from about 0.75 to about 6.0 moles of said hypohalite ion in a reaction mixture comprising (a) an aqueous electrolyte solution containing from 4.0 to about 65 percent electrolyte by weight, and preferably (b) an inert water-immiscible organic solvent in which the halogenated methylenediphosphonates and halogenated phosphonoacetates are soluble to at least 5 percent by weight, the temperature of the reaction being in the range of from 0 to C., the pH of the aqueous solution being greater than about 7 and the reaction time being from about 1 minute to about 2.0 hours.

DETAILED DISCLOSURE The present invention is valuable in that the reactants and the reaction conditions mentioned above can be adjusted in the manner outlined and exemplified below to produce unexpectedly high yields of monoand dihalo-derivatives of the methylenediphosphonates and phosphonoacetates.

For instance, if the starting methylenediphosphonate reactant is either tetramethyl methylenediphosphonate or tetraethyl methylenediphosphonate, the reaction product is either a monohalogenated tetramethyl methylenediphosphonate, or a dihalogenated tetramethyl methylenediphosphonate, a monohalogenated tetraethyl methylenediphosphonate or a dihalogenated tetraethyl methylenediphosphonate depending on the reaction conditions employed within the ranges specified above. Thus, by the present invention, the process can be used to prepare such compounds as tetramethyl monochloromethylenediphosphonate, tetramethyl monobromomethylenediphosphonate, tetramethyl monoiodomethylenediphosphonate, tetramethyl dichloromethylenediphosphonate, tetra( difluoromethyl) dichloromethylenediphosphonate, tetramethyl dibromomethylenediphosphonate, tetramethyl diiodomethylenediphosphonate, tetraethyl monochloromethylenediphosphonate, tetraethyl monobromomethylenediphosphonate, tetraethyl rnonoiodomethylenediphosphonate, tetraethyl dichloromethylenediphosphonate, tetraethyl dibromomethylenediphosphonate, dimethyl diethyl dibromomethylenediphosphonate, methyl triethyl bromoiodomethylenediphosphonate and tetraethyl diiodomethylenediphosphonate.

1f the starting phosphonoacetate reactant is either triisopropyl phosphonoacetate, tripropyl phosphonoacetate, triethyl phosphonoacetate, tributyl phosphonoacetate or triisobutyl phosphonoacetate, the reaction product is either a monohalogenated or a dihalogenated trialkyl phosphonoacetate. Thus, by the present invention the process can be used to prepare such compounds as triethyl monochlorophosphonoacetate, triethyl monobromophosphonoacetate, triethyl monoiodophosphonoacetate, triethyl diiodophosphonoacetate, triisopropyl dibromophosphonoacetate, triisopropyl diiodophosphonoacetate, triisopropyl dichlorophosphonoacetate, tributyl monobromophosphonoacetate, tributyl diehlorophosphonoacetate, tributyl diiodophosphonoacetate, ethyl isopropyl isobutyl dibromophosphonoacetate, tributenyl dibromophosphonoacetate, tri(2-chloroethyl) diiodophosphonoacetate, tri( 3-iodopropenyl) diiodophosphonoacetate and 2,3-dibromopropyl dimethyl dibromophosphonoacetate.

The reaction system is a fairly complex one, but by adhering to the conditions set forth above and more fully explained in the following discussion, highyields of any of the foregoing compounds can be prepared.

The embodiment of this invention according to which a monohalomethylenediphosphonate is prepared is illustrated by the following equation:

The embodiment of this invention according to which a monohalophosphonoacetate is prepared is illustrated by the following equation:

In the above equations OX represents a hypohalite ion with X being a halogen atom selected from the group consisting of chlorine, bromine, and iodine atoms, M is an electrolyte not containing a halide X that can be displaced by the OX used; S is an inert, water-immiscible, organic solvent, if one is employed; R is selected from the group consisting of methyl, ethyl, halomethyl and haloethyl; and R is selected from the group consisting of alkyl, alkenyl, haloalkyl and haloalkenyl radicals containing from two to four carbon atoms.

For purposes of understanding the present invention, the hypohalite reactant is depicted simply as OX1 rather than as an inorganic hypohalite compound. It is to be understood that the essential reaction moiety is the hypohalite ion. lt can either be introduced as an inorganic hypohalite such as NaOBr, NaOCl, NaOl, or other equivalent alkali metal and alkaline earth metal forms. Alternatively, the hypohalite ion can be generated in situ by means described below.

It has now been discovered that surprisingly high yields of a monohalogenated product can be obtained using from about 0.75 to about 1.10 moles of hypohalite to one mole of methylenediphosphonate or phosphonoacetate. It is preferred, for maximum yields that from about 0.95 to about 1.10 moles of hypohalite ion to one mole of either methylenediphosphonate or phosphonoacetate be employed. It is important that no more than about 1.10 moles of hypohalite per mole of methylenediphosphonate or phosphonoacetate be present in the above reaction in order to prepare high yields of a monohalogenated compound. A larger portion of hypohalite ion tends to carry the reaction on to form the dihalo methylenediphosphonates or phosphonoacetates as explained below. The reactions of equations 1 and [I can be terminated, as discussed hereinafter, producing surprisingly high yields of monohalo methylenediphosphonates or phosphonoacetates.

According to a further embodiment of this invention, the above reaction can be allowed to continue, producing the corresponding dihalo methylenediphosphonates or phosphonoacetates. In this embodiment of the invention, the hypohalite ion reacts with the monohalo reaction product of equations l and Il to produce the corresponding dihalo methylenediphosphonates or phosphonoacetates. To provide sufiicient hypohalite ion to form dihalo ester compounds, a large excess of hypohalite ion should be used. It has been discovered that the highest yield of dihalo methylenediphosphonate or phosphonoacetate is obtained by using from about 2.0 to about 6 moles of hypohalite ion per one mole of methylenediphosphonate or phosphonoacetate. It is preferred that from 2.05 to about 2.10 moles of hypohalite ion be used per one mole of methylenediphosphonate or phosphonoacetate in the foregoing reaction to favor formation of the dihalo methylenediphosphonates or phosphonoacetates.

The dihalogenation embodiment of the present invention is more fully illustrated in the following equations wherein all terms are as defined in equations I and 11. Equation 11] can be considered in conjunction with equation I above in which the XCl-l(PO R2)2 starting material is thoughtof as the reaction product of equation l and equation N can be considered in conjunction with equation ll above in which the R' PO CXH- COOR starting material is thought of as the reaction product of equation II.

By the same token, the preparation of the dihalo esters can proceed according to the equation 111 or equation IV reaction sequences by beginning with a monohalo methylenediphosphonate or phosphonoacetate obtained from any source, i.e., from equations l or II or from any other suitable reactions. It will be appreciated that when this approach is taken, the two X's need not be the same. In this latter event, highest yields of dihalo methylenediphosphonate or phosphonoacetate are obtained by using from about 1 to about 3 moles of hypohalite ion per 1 mole of monohalo methylenediphosphonate or phosphonoacetate, and preferably from about 1.05 to about 1.10 moles of hypohalite ion per 1 mole of monohalo methylenediphosphonate or phosphonoacetate in the foregoing reactions Ill and IV.

When the highly preferred method of using anorganic solvent is employed, (in the case of the phosphonoacetates this highly preferred embodiment is required for good yields). the halogenation reactions of this invention are heterogeneous reactions between two substantially immiscible liquid phases, viz, an organic phase and an aqueous electrolyte phase.

Using an inert organic solvent is not a critical aspect of this invention. Some of the halogenated tetramethyl and tetraethyl methylenediphosphonates are obtained when large proportions of electrolyte are used even without the addition of an inert organic solvent as illustrated in example Vl; however, the use of an inert organic phase solvent is highly preferred, primarily because of overall process efficiency, i.e. less time need be consumed and in some instances lower levels of electrolyte can be employed.

The preferred organic phase is comprised of an inert, waterimmiscible, organic solvent in which the halogenated methylenediphosphonates and/or phosphonoacetates are solubleand which is neither halogenated bynor oxidizedby the hypohalite and does not react with base at the reaction conditions. To be suitable for use in the process of this invention, the inert organic solvent must be capable of dissolving the halogenated methylenediphosphonate and/or phosphonoacetate reaction products to at least 5 percent by weight of the solvent.

Examples of organic materials which can be used generally in the process of this invention include benzene, trichlorobenzene, and ethers. Preferred organic solvents suitable for use in this invention are polyhalogenated materials such as chloroform, carbon tetrachloride and symtetrachloroethane. The inert organic materials most preferred for use in the process of this invention are halogenated compounds such as carbon tetrachloride.

The aqueous electrolyte phase is considered the reaction zone and it should have an electrolyte concentration of from about 4.0 to about 65 percent by weight. The exact electrolyte concentration can vary throughout this range and will depend on the specific reaction being practiced. However, when preparing tetramethyl dihalomethylenediphosphonates and trihydrocarbyl dihalophosphonoacetates it is preferred that from about to about 65 percent by weight of electrolyte be employed. This range is preferred when preparing tetramethyl dihalomethylenediphosphonates because if amounts of electrolyte substantially less than percent by weight are employed, the corresponding product yield is substantially reduced.

The electrolyte for use in thisprocess can be a compound selected from the general class known as electrolytes which are water soluble to at least 5.0 percentby weight. More specifically, the electrolytes for use in theaqueous phase can be a water-soluble inorganic base such as NaOH or KO; or a water-soluble inorganic salt which will notreact when the hypohalite which is used, such as NaCl, Na CO NaNO K CO Kl, Na,SO,, K 80 NaOOCCll and the like or any other compounds of the general class known as electrolytes which are water soluble and which will not react with the hypohalite, e.g., the alkali metal borates, carboxylates, and phosphates. Care must be taken that the electrolyte chosen is not a salt of a halide other than that which is being reacted with the methylenediphosphonate or phosphonoacetate. if this care is not taken, substitution of halides other than that desired halide which is being reacted with the methylenediphosphonate or phosphonoacetate could occur as a competing reaction.

The reactions set forth in equations l-lV must be conducted above a pH of 7 at a temperature of from about 0 to about 75 C. These reactions take from about I minute to about 2 hours depending upon the rate of addition of reactants, temperature and general reaction conditions. in the preferred embodiment of the present invention, the methylenediphosphonate or phosphonoacetate is added to a mixture of the aqueous electrolyte phase and the inert organic solvent and is stirred vigorously. Vigorous stirring breaks the organic phase into tiny discrete globules intermixed with the aqueous phase. This agitation of the mixture is continued, while adding to the reaction mixture either OCl', OBr or Ol.

It is important in directing the process of the present invention toward the monohalide product (equations 1 and II) that the hypohalite be added to the methylenediphosphonate or phosphonoacetate in order to minimize any excess of hypohalite present during the reaction. While the foregoing represents the preferred method of adding reactants in the process of the present invention, the hypohalite can be generated in the aqueous phase subsequent to the addition of the methylenediphosphonate or phosphonoacetate or the methylenediphosphonate or phosphonoacetate or the methylenediphosphonate or phosphonoacetate can be added rapidly to the hypohalite.

The reactant hypohalite ion can be added directly to an aqueous solution or can be generated in situ such as, for example, by repeated additions of small amounts of the desired halogen such as liquid bromine, chlorine gas, or iodine as a solid or solution. Suitable hypohalites which can be added directly include all alkali metal and alkaline earth hypochlorites, hypobromites and hypoiodites. Examples of suitable hypohalite compounds include CalOClh; Ca(OBr),, KOCI, KOBr, NaOCI, and NaOBr. It is preferred that the hypohalite ion be generated in situ for reasons stated hereinafter.

Generally, the solubility of the methylenediphosphonate and/or phosphonoacetate in the aqueous electrolyte solution can be substantially controlled, i.e., increased or decreased, by decreasing or increasing the electrolyte concentration, respectively. The greater the electrolyte concentration in the aqueous solution, the lower is the solubility of the methylenediphosphonate and phosphonoacetate reactants in the aqueous solution. The reverse is also true, that is, the lower the electrolyte concentration the greater the solubility of these reactants. The solubility of the methylenediphosphonates and/or phosphonoacetates in the aqueous reaction electrolyte solution can also be increased or decreased by increasing or decreasing the temperature, respectively.

Generally, whether the reaction product is the monohalo or dihalo derivative of a methylenediphosphonate or phosphonoacetate is controlled by the proportion of the hypohalite reactant employed. If the desired end product is the monohalogenated derivative, from about 0.75 to about l.l0 moles of hypohalite ion per 1 mole of methylenediphosphonate or phosphonoacetate, should be used. For maximum yields of the monohalide it is preferred that from about 0.95 to about 1.10 moles of hypohalite ion per mole of methylenediphosphonate or phosphonoacetate be employed. Amounts of hypohalite greater than about l.l0 moles per mole of methylenediphosphonate or phosphonoacetate tend to favor the formation of increasing amounts of dihalogenated product.

Recovery of the halogenated methylenediphosphonate and phosphonoacetate products from the organic solvent, if one is employed, can be performed by cessation of stirring which allows the aggregation of tiny discrete inert organic phase globules containing the halogenated methylenediphosphonate or phosphonoacetate. The inert organic phase containing the halogenated methylenediphosphonates or phosphonoacetates can then be readily separated from the aqueous solution by conventional decanting methods, and the halogenated methylenediphosphonates or phosphonoacetates extracted from the inert organic material by methods old in the art, e.g., column chromatography, selective extraction, distillation or fractional crystallization.

At extreme conditions, e.g., 6 moles of hypohalite ion per mole of methylenediphosphonate or phosphonoacetate reactant and 75 C., the alkenyl esters can react further with the hypohalite to form halohydrins by known reactions. Therefore, in general, these extreme conditions should be avoided when alkenyl esters are used.

In practicing each of the foregoing embodiments of this invention care must be taken that the reaction temperatures are not so high that the hypohalite ion (OX) is converted to the halate ion (XOf) creating a deficiency of hypohalite ion in the reaction mixture. For example, temperatures up to about 50 C. are usually satisfactory for the avoidance of hypochlorite conversion, but are only marginally satisfactory for hypobromite conversion avoidance. However, by generating the hypohalite in situ the reactions can be conducted at substantially higher temperatures, i.e., over C., as the hypohalite ion reacts with the methylenediphosphonate or phosphonoacetate before there is time for it to disproportionate to from halate ion.

The temperature must not be so high that it reaches a point at which undesirable ester saponification becomes significant. The temperature at which saponification occurs is governed by the pH of the system that is being used, higher pH favoring more saponification. Ester saponification to a significantly detrimental degree will occur above about 75 C. when the pH of the system is near neutrality, i.e., from about pH 7 to about pH 9. However, at highly basic pHs saponification will occur to a detrimental degree at lower temperatures. if an organic solvent is employed, the temperature cannot be higher than the boiling point of the inert organic solvent as the solvent would be lost from the reaction system. For example, the boiling point of carbon tetrachloride is 77 C., and the boiling point of chloroform is 61 C.

Care must be taken to avoid excessive formation of hypohalous acid in the reaction system. The aqueous reaction medium must be kept basic enough to sustain the desired hypohalite ion. If the pH of the reaction system drops below about 7 the equilibrium HOX-tlOX+H*will shift to the left, causing the hypohalite ion to disappear. Consequently, the pH of the reaction system must be kept above about 7 in the case of chlorine addition, and should be above about a pH of 8 for bromine addition and above a pH of 10 for iodine addition. The reaction for each halide may be conducted with a pH as high as about 14 and it is preferable that the pH of the reaction solution be above about 1 1.

The tetraalkyl methylenediphosphonates used as starting materials in this invention can be prepared by reacting dibromomethane with a trialkyl phosphite in accordance with the following equation:

wherein R is an alkyl radical selected from the group consisting of methyl and ethyl. The trialkyl phosphite in this reaction can be derived from a primary alcohol and phosphorus trichloride. The dibromomethane is a high temperature reaction product of methane and bromine. A more detailed discussion of the foregoing appears in US. Pat. No. 3,251,907 of Clarence H. Roy, issued May 17, 1966. Trialkyl phosphonoacetates can be prepared as follows: P(OR) ClCH CoOR'i R 'PO -CH -COOR+R'Cl or they canbe purchased commercially.

The compounds of this invention have the formula k PO CXPO R wherein each R is selected from the group consisting of methyl, ethyl, halomethyl and haloethyl radicals, one X is selected from the group consisting of bromine and iodine atoms and the other X is selected from the group consisting of chlorine, bromine and iodine atoms. These compounds are effective extreme pressure additives for lubricant compositions as disclosed in the copending application of Robert Earl Wann, Denzel Allan Nicholson and Ted Joe Logan, Ser. No. 762,966, filed Sept. 26, 1968 entitled Lubricant Composition. As disclosed in that application, the bromo and iodo derivatives of the methylenediphosphonate esters are more effective extreme pressure additives than the corresponding chloro derivatives. Preferably, both Xs are either iodine or bromine atoms. This application is incorporated herein by reference.

The process of this invention is illustrated by the followin examples but is not limited thereto.

EXAMPLE 1 Tetraethyl Monobromomethylenediphosphonate An aqueous electrolyte solution was prepared by adding 8.55 g. (.0535 mole) of bromine to an 18 percent sodium hydroxide (30 g.) aqueous solution at 10 C. in a 250 ml. glass beaker. This produced about 0.05 mole of NaOBr and an electrolyte concentration dictated by the amount of bromine and NaOH. The pH of the solution was about 13.5 fifty milliliters of CC], was added to this solution forming a two-phase system. The mixture was then cooled to about 6 C.

While stirring the. mixture vigorously with a magnetic stirring device, 14.4 g. (0.05 mole) of tetraethyl methylenediphosphonate was added to the two-phase system. After allowing the mixture to react for about 5 minutes, the organic phase was separated from the mixture using a separatory funnel. Then, CC], was separated from the ester reaction product by using a flash evaporator (the organic phase is placed in a heated rotating vessel to which an aspirator is attached causing a vacuum which distills off CCL).

Using anuclear magnetic resonance spectrometer, a P nmr analysis was made indicating 48 percent of the product was tetraethyl monobromomethylenediphosphonate, 10 percent was tetraethyl dibromomethylenediphosphonate and 42 percent was unreacted tetraethyl methylenediphosphonate. The monobromomethylenediphosphonate ester can be separated from the reaction product by fractional crystallization. Results similar to the foregoing can be obtained if the pH is maintained about 1 1.

EXAMPLE ll Tetraethyl Monobromomethylenediphosphonate All the steps in example I were repeated using the same equipment and reactants; however, in this example the electrolyte concentration of the aqueous phase was increased by adding 20 g. of K CO to the aqueous phase. Additionally several milliliters of H 0 were added. This produced an initial electrolyte concentration of about 35 percent (based on K CO After the reaction was complete and the product separated from the mixture, a P nmr analysis revealed that 60 percent of the product was tetraethyl monobromomethylenediphosphonate, l5 percent was tetraethyl dibromomethylenediphosphonate, and the remaining 25 percent was unreacted tetraethyl methylenediphosphonate.

Results similar to those in the foregoing examples can be obtained using many other electrolytes, e.g., NaOH, KOH, Na CO and N aNO Also, similar results can be obtained if the CCL, organic solvent is replaced by chloroform or sym-tetrachloroethane.

Similarly, tetramethyl methylenedisphosphonate could be employed in the foregoing examples replacing tetraethyl methylenedisphosphonate producing a predominately tetramethyl monobromomethylenediphosphonate product and NaOCl or NaOI could be employed, replacing NaOBr, to produce predominantly tetramethyl monochloroor monoidomethylenediphosphonate product.

EXAMPLE Ill Tetramethyl Dichloromethylenediphosphonate Three hundred and fifty grams of K CO were dissolved in 510 g. of an aqueous solution containing 5.25 percent NaOCl and 4.1 percent NaCl in a 2-liter glass beaker. The final solution had a pH of 13.5 and an electrolyte concentration of about 41 percent (based on K CO This solution contains about 0.36 moles of hypochlorite. To this solution, 200 ml. of CHCl was added forming a two-phase system. The total system was then cooled to 10 C.

15.0 g. (0.065 mole) of tetramethyl methylenediphosphonate was added, with vigorous stirring, to the two-phase system. After 10 minutes, the organic layer was removed from the aqueous layer with a separatory funnel and was, thereafter, washed with water. CHCl was then removed from the organic phase by flash evaporation. A P nmr analysis on the residue showed that 93 percent of the material was tetramethyl dichloromethylenediphosphonate. The weight of the residue was 19.4 grams.

Results similar to the foregoing can be obtained if the organic solvent employed is carbon tetrachloride or symtetrachloroethane.

EXAMPLE IV Tetraethyl Dichloromethylenediphosphonate An aqueous electrolyte solution (2,120 g.) containing 5.25 percent NaOCl and 4.1 percent NaCl which contained 1.5 moles of hypochlorite and had a pH of about 1 1.5 and an electrolyte concentration due only to the sodium chloride was mixed in a 3 liter glass beaker with 800 ml. of Cl-lCl to form a two-phase system. To this two-phase system, cooled to 12 C., was added 100 g. (0.35 moles) of tetraethyl methylenediphosphonate, while stirring vigorously. After about 20 minutes the Cl-lCl layer (organic phase) was separated and the CHCl removed by flash evaporation. An analysis by P nmr indicated that 92 percent of the product was tetraethyl dichloromethylenediphosphonate. The distilled (in vacuo) ester was obtained in a 76 percent yield.

EXAMPLE V Tetraethyl Dibromomethylenediphosphonate Two hundred and fifty ml. of CCl was mixed in a 2-liter glass beaker with an aqueous electrolyte solution consisting of 0.94 moles of bromine and 468 g. of a 18 percent NaOl-l solution. This formed a two-phase system which was then cooled to 5 C. The aqueous electrolyte phase had an electrolyte concentration dictated by the amount of bromine and NaOH and a pH of about 13.7. It also contained 0.94 moles of hypobromite.

At this point 100 g. (0.35 moles) of tetraethyl methylenediphosphonate was added with stirring to the twophase system. After addition of the ester, the ice bath was removed and the mixture stirred for minutes. The layers were then separated and the CCl layer (organic phase) was washed several times with water. The CCL was then removed from the ester by flash evaporation. P nmr analysis indicated that the crude product was 95 percent tetraethyl dibromomethylenediphosphonate. Distillation (in vacuo) gave the desired product at a 66 percent yield.

EXAMPLE V1 Tetraethyl Dichloromethylenediphosphonate An aqueous electrolyte solution (1,500 g.) containing 5.25 percent NaOCl 1.06 moles) and 4.1 percent NaCl was mixed with 1,000 g. K CO in a 3-liter glass beaker. The electrolyte concentration was about 40 percent (based on K CO giving a pH of about 12. The solution was cooled to about 20 C.; 57.6 g. (0.20 moles) of tetraethyl methylenediphosphonate was added slowly. After stirring for about minutes, the aqueous electrolyte solution was extracted with Cl-lCl lCCl (about 3: l and the organic phase separated. After removal of the solvents from the organic phase, a P nmr spectrum indicated that about 95 percent of the residue was tetraethyl dichloromethylenediphosphonate. The product weight was approximately 66 g.

As noted above, the halogenated tetramethyl and tetraethyl methylenediphosphonate compounds prepared according to the present invention can be converted to their corresponding water soluble salts, in which form they are valuable as detergency builders. The water-soluble salts especially useful are the alkali metal (sodium, potassium) ammonium or substituted ammonium fomis. Conversion of the esters described herein can be readily performed by an ordinary hydrolysis and neutralization with a suitable base, e.g., sodium hydroxide. The water-soluble salts of the halogenated methylenediphosphonates are useful as builders with a wide variety of organic synthetic detergents including anionic, nonionic. ampholytic and zwitterionic detergents.

EXAMPLE Vll Tributyl Dibromophosphonoacetate Tributyl phosphonoacetate, 17.2 g. (0.053 mole) is added to a 2-liter flask containing a two phase system of water, 4.5 percent NaBr, and carbon tetrachloride. 0.098 mole (about 10 percent excess) of NaOBr in water is then added slowly with stirring. The mixture is further reacted for 10 minutes at 0 to 5 C., and then allowed to separate into layers. The car- Methylenediphosphonate or phosphonoacetate Hypohallte reactant reactant Reaction products Diruethyl dlethyl KOI Diethyl dirnethyl dliodoligathytlenediphosmethylenediphosphonate. p one e.

Chloromethyl 2- NaO C1 Chloromethyl 2-chloroethyl chloroethyl dlmethyl dimethyl dic111oromethylenediphosmethylene-diphosphonate. phonate.

Diisopropyl propyl NaOBr Dlisopropyl propyl phosphonoacetate. dibromo-phosphono- Tri(dlfluoromethy1) KOBr Trl(difluoromethyDil-bromq 2-br0moethy1 ethyl dlbromomethylmethylene enedlphosphonate. diphosphonate.

Tri(2-isobutyl) phos- NaOI Iri(2-1s0butyl) dllodophosphonoacetate. phonoaeetates.

3-chl0r0propeny1 2- Ca(0C1) 3-ch10r0propenyl 2-bromobromopentenyl pentenyl 2-iodobutenyl 2-lodo-buteny1 dichlorophosphonophosphonoacetate. acetate.

'Irlpropyl monochloro- NaOBr 'lripropyl monobromomonophosphonoacetate. chlorophosphonoaeetate. Triethyl monobromo- NaOI Triethyl monobromomonophosphonoacetate. lodophosphonoacetate.

Tributyl phospbono- Liquid Tributyl dibromophosacetate. bromine] phonoacetate.

NaOH.

Tripropenyl phospho- Ca(OBr) Tripropenyl dibromophosnoacetate. phonoacetate.

EXAMPLE V111 Triethyl Dibromophosphonoacetate One mole 226.0) grams of triethyl phosphonacetate is placed in a reaction flask with 4 moles 160.0 grams) NaOH in H 0 and 500 grams of Na SO. at 0 C. and stirred vigorously. Two moles (320.0 grams) Br are then dripped into the twophase system. After the Br has been added the mixture is stirred for 10 minutes more at 0 C. At this time the layers are separated and the H 0 layer extracted three times with CCl,. The CCl, layer is dried over anhydrous sodium sulfate for several minutes then filtered and the solvent removed by evaporation. The product, triethyl dibromophosphonoacetate, E is obtained in -100 percent yield and is percent pure.

EXAMPLE 1X Triethyl Dichlorophosphonoacetate One mole (226 grams) of triethyl phosphonoacetate is placed in a reaction flask with four moles grams) of NaOH and 500 grams of potassium carbonate in H O at 0 C. and vigorously stirred. Two moles (142.0 grams) Cl are then bubbled into the two-phase system. After the chlorine has been added, the mixture is stirred for 10 minutes more at 0 C. i At this time the layers are separated and the water layer is ex- :tracted five times with CCl The CCl, layer is dried over anlhydrous sodium sulfate for several minutes, then filtered and the CCl, is removed by evaporation. The product, triethyl dichlorophosphonoacetate, is obtained in 80-100 percent yield and is 90 percent pure.

EXAMPLE X product layer and dried over anhydrous sodium sulfate for minutes, then filtered and the solvent removed by evaporation. The product, triethyl monobromophosphonoacetate, is obtained in 80-100 percent yield and is =60 percent pure.

EXAMPLE Xl Triethyl Monochlorophosphonoacetate One mole (226.0 grams) of triethyl phosphonoacetate is placed in a reaction flask and cooled to 0 C. and stirred vigorously as l mole of NaOCl is added slowly in H 0 solution containing 150 grams of Na CO After addition is complete, the mixture is stirred for an additional minutes. At this time the layers are separated and the water layer rinsed with CCl The CC] rinse is combined with the original product layer and dried over anhydrous sodium sulfate for minutes, then filtered and the solvent removed by evaporation. The product, triethyl monochlorophosphonoacetate, is obtained in 80-100 percent yield and is -60 percent pure.

When, in the above example, the following compounds listed in column 1 are substituted for the triethylphosphonoacetate on a molar basis and the compounds listed in column 2 are substituted for the NaOCl on a molar basis, substantially equivalent results are obtained in that the compounds listed in column 3 are formed in good yield.

Methylenediphosphonate or phosphonoacetate Hypohalite The dibromoand diiodo-methylenediphosphonates disclosed in examples l-Xl are effective extreme pressure additives when used at the 5 percent level in e.g., a Kendall base SAE mineral oil. They are more effective than the corresponding dichloromethylenediphosphonate esters.

It is to be understood that within the broad ranges set forth hereinbefore and in the claims, one skilled in the art can readily optimize the conditions for any particular halogenated methylenediphosphonate or phosphonoacetate desired. it is also to be understood that at the extreme limits of the described ranges, insignificant amounts of product may be obtained; however, as explained above one skilled in the art can readily optimize the conditions for any one halogenated methylenediphosphonate or phosphonoacetate derivative.

What is claimed is: l. A process which comprises the steps of reacting, with vigorous stirring, a compound selected from the group consisting of (l) methylenediphosphonates having the formula ll Po CliPO R in which each R is selected from the group consisting of methyl, ethyl, halomethyl and haloethyl radicals and (2) phosphonoacetates having the formula R 'l 'o CH,COOR in which each R is selected from the group consisting of alkyl, alkenyl, haloalkyl, and haloalkenyl radicals containing from two to four carbon atoms with a hypohalite ion selected from the group consisting of OCl, OBr' or 01',

the molar proportions of the reactants corresponding to one mole of said ester reactant to from about 0.75 to about 6.0 moles of said hypohalite ion,

in a two-phase reaction mixture comprised of an aqueous' phase containing from 4 to about 65 percent electrolyte, by weight and an inert water-immiscible organic solvent phase in which the halogenated methylenediphosphonates and halogenated phosphonoacetates formed in the reaction are soluble to at least 5 percent by weight,

the temperature of the reaction being in the range of from 0 to 75 C., the pH of the aqueous solution being greater than about 7,

and the reaction time being from about I minute to about 2 hours. 2. The process of claim 1 wherein (a) the methylenediphosphonate or phosphonoacetate and (b) the hypohalite ion are present in a molar ratio of about l:0.75 to about 1:1.10.

3. The process of claim 2 wherein (a) the methylenediphosphonate or phosphonoacetate and (b) the hypohalite ion are present in a molar ratio of about 110.95 to about l:l.l0 and wherein the aqueous electrolyte solution contains from about 15 to about 65 percent electrolyte by weight.

4. The process of claim 3 wherein the inert organic solvent is selected from the group consisting of carbon tetrachloride, chloroform and sym-tetrachloroethane.

5. The process of claim 4 wherein the pH is above 1 l.

6. The process of claim 2 wherein each mole of methylenediphosphonate or phosphonoacetate is reacted with from about 2.0 to about 6.0 moles of a hypohalite ion.

7. The process of claim 8 wherein the amount of hypohalite is from about 2.05 to about 2.] moles.

8. The process of claim 7 wherein the inert organic solvent is selected from the group consisting of carbon tetrachloride, chlorofonn, and sym-tetrachloroethane.

9. The process of claim 8 wherein the pH is above 1 l.

10. The process of claim 1 wherein each R is methyl and the aqueous solution contains a: least 15 p ercent electrolyte.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Rs. ,525,188 Dated November 30, 1971 Invenggr(3) J'Ohh Downing Curry It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

olumn 3, line 26, before "diiodophosphonoacetate" insert dichlorophosphonoacetate, triethyl dibromophosphonoacetate, triethyl Column 5, line 39, delete "K0" and insert therefor KOH Column 5, line 75 to Column 6, line 1, after "phosphonoacetate" at Column 5, line 75 delete "or the methylenediphosphonate or phosphonoacetate" Column 7, line 46, delete "R PO CXPO R and insert therefor Column 8, line 18, after "maintained" and before "about" insert Column 8, line 47, delete "monoido-" and insert therefor monoiod Column 12, line 9, delete "R P0 CHPO R and insert therefor R P0 11 F0 1? Signed and sealed this 18th day of July' 1 972.

(SEAL) t: L Attes m EDWARD M.FLETCHER JR. ROBERT- GOTTSCHALK Attesting Officer Commissioner of Patents

Claims

2. The process of claim 1 wherein (a) the methylenediphosphonate or phosphonoacetate and (b) the hypohalite ion are present in a molar ratio of about 1:0.75 to about 1:1.10.
3. The process of claim 2 wherein (a) the methylenediphosphonate or phosphonoacetate and (b) the hypohalite ion are present in a molar ratio of about 1:0.95 to about 1:1.10 and wherein the aqueous electrolyte solution contains from about 15 to about 65 percent electrolyte by weight.
4. The process of claim 3 wherein the inert organic solvent is selected from the group consisting of carbon tetrachloride, chloroform and sym-tetrachloroethane.
5. The process of claim 4 wherein the pH is above 11.
6. The process of claim 2 wherein each mole of methylenediphosphonate or phosphonoacetate is reacted with from about 2.0 to about 6.0 moles of a hypohalite ion.
7. The process of claim 8 wherein the amount of hypohalite is from about 2.05 to about 2.1 moles.
8. The process of claim 7 wherein the inert organic solvent is selected from the group consisting of carbon tetrachloride, chloroform, and sym-tetrachloroethane.
9. The process of claim 8 wherein the pH is above 11.
10. The process of claim 1 wherein each R is methyl and the aqueous solution contains at least 15 percent electrolyte.