CS209178B1 - Manufacturing process of tetramethylester and tetrakis /1-methylethyl/ester of dichlormethylendiphosphone acid - Google Patents

Description

(54) A method for producing tetramethyl ester and tetrakis (1-methylethyl) dichloromethylenediphosphonic acid ester

The present invention relates to a process for the preparation of dichloromethylenediphosphonic acid tetramethyl ester (I) and atetrakis (1-methylethyl) dichloromethylenediphosphonic acid ester (II), which are valuable intermediates in the synthesis of detergent components, respectively. as additives for oils intended for extreme pressures. Suitable detergent ingredients obtainable from the products of this invention include alkali metal salts, variously substituted amines, or ammonium salts of dichloromethylenediphosphonic acid (clodronic acid) derived from esters I and II. Tetramethyl ester or tetrakis (1-methylethyl) dichloromethylenediphosphonic acid (I) or tetrakis (1-methylethyl) ester; (II) can be converted to these salts by various methods. An example of such a preparation is hydrolysis of boiling concentrated hydrochloric acid, or pyrolysis in the case of 1-methylethyl ester, to give the free acid followed by addition of a base such as sodium hydroxide to the acid to form the corresponding salt (US 3,624,188; US 3,422,021; Belg. 627,205; Brit., 1,026,366).

Scheme 1

CH ₂ X _{2 +} 2

CH ₂ X ₂ + 2

PORE/

NaPO / OR /

after / or / ₂ (fc)

P0 / 0R / ₂

PO / OR /

PO / OR / ₂

X = halogen

III R = CH ₃

IV R = CH (CH ₃ ) ₂

IR = CH ₃

II R = CH (CH ₃ ) ₂

The present process for the preparation of tetramethyl ether and tetrakis (1-methylethyl) dichloromethylenediphosphonic acid ester (I), respectively. (II) can be summarized under General Scheme 1, wherein the second reaction step (c), the chlorination of the methylene diphosphonic acid tetraalkyl esters (III and IV, respectively) has been nearly perfected over time. The yield of reaction (c) using hypochlorite in an aqueous medium, optionally in the presence of carbon tetrachloride, is up to 85% (J. Organometal. Chem. 13,199 (1968); U. S. 3,624,188; U. S. 3,772,412).

X = halogen

R = CH _3, CH (CH _{3) 2}

P (OR), ^CH 2 ^X 2

RX + CH ₂ XPO / OR / 2

PORE/,

CH,

PO / OR /,

PO / OR /,

The starting material for the halogenation, the methylene diphosphonic acid tetraalkyl esters (III or IV), is much more difficult to prepare. The Michaelis-Arbus reaction (a), which proceeds very easily in primary halides, is associated with considerable complications in dihalomethanes. The yield of the reaction of diiodomethane with trialkyl phosphite (J. Chem. Soc. 1955.3092) did not exceed 25%, but was even lower in the case of dibromomethane (J. Amer. Chem. Soc. 75.5738 (1953); J. Chem. Soc. 1947, 1465). The difficulties due to the conflicting claims of both stages of the reaction have been partially alleviated by carrying out the reaction under strictly controlled reaction conditions, with the resulting alkyl halide being constantly distilled off. For example, a mixture of methylene bromide and tris (1-methylethyl) phosphite requires a precisely rising temperature from 143 ° C to 185 ° C, with a reaction time of about 16 hours; the yield is then about 90% (U. S. 3,251,907). The differences in the boiling points of the methyl ester are already disadvantageous that the compound III is prepared from the ester IV via the corresponding free acid by esterification (J. Organometal. Chem. 13, 199 (1968)).

X = halogen

R = CH ₃ , CH (CH ₃ ) _{2 and 2} x ₂

NaP0 / 0R /

- ^ * NaX + CH ₂ XPO / OR / ₂

NaP0 / 0R /

CH,

PO / OR / ₂ after / or / ₂

The Michaelis-Becker reaction (b) is even more difficult for dihalomethanes (J. Chem. Soc. 1959, 2266); even in two separate stages, the total reaction yield does not exceed about 40% (Monatsh. Chem. 81, 202 (1950)) and is practically not used for the preparation of esters III and IV.

The principle of the tetramethyl ester production process, respectively. The tetrakis (1-methylethyl) dichloromethylenediphosphonic acid ester (I or II) according to the invention consists in the formation of the trichloromethylphosphonic acid dimethyl ester (V) or the dimethyl ester of trichloromethylphosphonic acid (V) or (II). trichloromethylphosphonic acid bis (1-methylethyl) ester (VI) (Zh. Obch. Chim. 16, 1521 (1946)) is treated with trimethylphosphite and the like. tris (1-methylethyl) phosphite under conditions permitting a radical reaction, preferably under irradiation with a medium pressure mercury lamp. The resulting tetramethyl ester I, respectively. tetrakis (1-methylethyl) ether II is mixed with excess trimethylphosphite, respectively. tris (1-methylethyl) phosphite, unreacted dialkyl ester V; VI and other products are isolated by conventional techniques such as distillation. Methyl chloride; The 1-methylethyl chloride was distilled off during the reaction. The third chlorine atom is practically unsubstituted under the conditions used.

VR = CH ₃

VI R = CH (CH ₃ ) ₂

IR = CH ₃ II R = CH (CH ₃ ) ₂

PORE/

- ⁱ - »- CCI ₃ PO / OR / ₂

PORE/.

CC1 after / or / ₂

The structure of the syrup-like tetramethyl ester of dichloromethylene diphosphonic acid (I) distilling without decomposition at about 100 ° C in a bath and 7 Pa resulted from elemental analysis compared to an authentic sample (U. S. 3,624,188) and from hydrolysis resulting in crystalline clodronic acid.

The structure of the crystalline dichloromethylenediphosphonic acid tetrakis (1-methylethyl) ester (II), m.p. 50 ° C, resulted from elemental analysis and comparison with an authentic sample (U. S. 3,772,412).

po / or / ₂

By irradiating a 1: 5 mixture of trichloromethylphosphonic acid dimethyl ester (V) and trimethylphosphite with a medium pressure mercury vapor lamp for 10 hours, about 40% of the dichloromethylenediphosphonic acid tetramethyl ester (I), respectively, is obtained. 80% (based on the converted dimethyl ester V). The yield increases gradually with the irradiation time. Component ratio greater than 5; 1 (P (OCH ₃ ) ₃ : CCl ₃ PO (OCH ₃ ) ₂ ) does not significantly increase the reaction rate. As the temperature rises, the reaction rate increases, but the reaction progress is satisfactory even at room temperature. Similar relationships are also valid for the reaction of the trichloromethylphosphonic acid bis (1-methylethyl) ester with tris (1-methylethyl) phosphite.

Compared to the previously described methods for the preparation of the compound I, the process according to the invention has the following advantages:

Use of carbon tetrachloride in place of dibromomethane or diiodomethane. j

2. Remove one reaction step (chlorination).

3. Experimental execution of the reaction is simple, using lower reaction temperatures, shorter times, with comparable yield.

Example 1

In a quartz apparatus equipped with a submersible medium pressure mercury lamp and a reflux condenser, 12.0 g of dimethyl trichloromethylphosphonic acid ester (V) was mixed under a nitrogen atmosphere.

Claims (3)

SUBJECT A process for the preparation of tetramethyl ester (I) and tetrakis (1-methylethyl) dichloromethylenediphosphonic acid ester (II), characterized in that the trichloromethylphosphonic acid dimethyl ester (V) and the trichloromethylphosphonic acid dimethyl ester (V) or (II) are prepared. trichloromethylphosphonic acid bis (1-methylethyl) ester (VI), treated with trimethylphosphite, resp. tris (1-methylethyl) phosphite, under conditions permitting a free-radical reaction at a temperature of + 10 ° C to +150 ° C under an inert gas atmosphere for 0.5 to 24 hours, and product I, respectively. II is isolated from the reaction mixture in a conventional manner, for example by distillation. and 40.0 g of trimethylphosphite, maintaining the temperature of the reaction mixture at 80 ° C. After 10 hours of irradiation, the reaction mixture was separated by fractional distillation, which in addition to 36.0 g of trimethylphosphite (50 ° C / 13 kPa) and the starting ester V (110 ° C / 1.2 kPa; 4.8 g) gave 6.4 g of tetramethyl acid ester dichloromethylenediphosphone (I) (100 ° C / 7 Pa). For C ₅ H ₁₂ Cl ₂ O ₆ P2 (301) calculated: 19.9% C, 4.0% H, 23.6% Cl, 20.6% P; Found: C, 20.1; H, 4.1; Cl, 23.3; The starting dimethyl ester V was prepared by refluxing a mixture of 20 g of trimethylphosphite and 50 ml of carbon tetrachloride for 3 hours; after evaporation of the carbon tetrachloride, V was distilled at 110 ° C and 1.2 kPa, yield 33.5 g, i.e. 92%. OF THE INVENTION 2. The process of claim 1, wherein the trichloromethylphosphonic acid dimethyl ester (V) and trimethylphosphite are reacted in a molar ratio of 1: 4 to 1: 6 at a temperature of 70 ° C to 90 ° C for 6 to 10 hours. 3. The process of claim 1, wherein the trichloromethylphosphonic acid bis (1-methylethyl) ester and tris (1-methylethyl) phosphite are reacted at a molar ratio of 1: 4 to 1: 6 at 70 ° C. to 90 ° C for 6 to 10 hours.