DE2158765C3 - Process for the production of alpha, omega-alkanediphosphonic acids - Google Patents

Description

example 1
1,2-ethane diphosphonic acid

₄₀

or 2-chloroethylphosphonate

ClC H P (O) (OR)

, ² , ⁴ _

with alkali dialkyl phosphite in ether or tetrahydrofuran realize.

All these conversions have the disadvantage that they are either cumbersome to carry out , pp

kind or that by-products by isomerization _s "C _2e H ₂₄ P, O _e (494,43): ih id id di ki i

27 g of tris-chloroethyl phosphite, which Mancius has obtained 13.8 g of PCl ₃ by introducing dry ethylene oxide, are mixed with 62 g of triphenyl phosphite in a distillation apparatus according to E η g 1

Heated to 150 ^° C. for 1 hour. Thereafter, ^the temperature is raised to 270 to 28O ⁰ C. and left 1.5 to

_{2 hours} tej _this temperature. During this, ~ 14g of 1,2-dichloroethane distill off. The residue of the tetraphenyl ester of 1,2-ethane-diphosphonic acid is

recrystallized from 1,2-dichloroethane. Yield 72g.

Mp. 150 to 153 ° C,

δ - -22.6 ppm in C ₂ H ₄ Cl ₂ .

cannot be avoided and thus no pure substances are obtained in good yield.

It has now been found that these disadvantages can be avoided in the preparation of, cu-alkanediphosphonic acids if triphenyl phosphite and tris-chloroalkyl phosphite are used in a molar ratio of 2 : 1 at temperatures of 210 to 300 ° C., preferably 220 to 280 ° C, heated and the ester obtained saponified in the usual way. The tetraphenyl ester of ω-alkane-diphosphonic acids of the general formula is formed in a smooth course of the reaction with elimination of dichloroalkane

Calculated ... P 12.53%;
found ... P 12.5%.
Molecular weight in benzene (ebull.)

508

_6o

QH ₅ O

OC ₆ H ₅

r n ρ

99 g of Tetraphenylesters is heated 3 to 4 hours in two bomb tubes with 400 ml of concentrated hydrochloric acid to 140 to 150 ⁰ C. The phenolic layer after opening of the bomb tubes separated, concentrated and the aqueous phase on a rotary evaporator to Trocknung_ and the residue recrystallized from methanol-ether recrystallized . Yield 34g.

Mp. 218 ⁰ C,

^δ = ²⁷ ' ² PP ^{m in water}
C ₂ H ₃ P ₂ O ₀ (190.04):

Calculated ... P 32.59%;

t J η ti en /

found ... P 32.5%.

Example 2

1,3-propane-diphosphonic acid

To 13.7 g of PCl ₃ are added dropwise with cooling and stirring 17.5 g of oxetane and then the formed heated for 1 hour at 60 ⁰ C. (ClC ₃ H ₆ O) ₃ P can be distilled for purification {δ = -141, 2 ± 1 ppm). 31.6 g of tris-3-chloropropyl phosphite are reacted with 62.0 g of triphenyl phosphite as described above. The orange-colored, cloudy reaction product is taken up in 1,2-dichloroethane and the solution is filtered off from the insoluble, phosphorus-containing residue. The solvent is evaporated off, a little dichloroethane is taken up again and the tetraphenyl ester is precipitated as a colorless oil by adding methanol. Yield 64g. The ester is saponified analogously to Example 1.

Claims (2)

Patent claims 1. A process for the preparation of Λ, ω-alkanediphosphonic acids, characterized labeled in ζ calibration et ri in that triphenyl phosphite and Trischloralkylphosphit in the molar ratio 2: 1 heated to from 210 to 300 ° C, preferably 220 to 280 ⁰ C and the ester obtained saponified in the usual way. 2. The method according to claim 1, characterized in that the ester by saponification with aqueous sodium hydroxide solution and subsequent introduction of hydrogen chloride gas into the free acid is convicted. where η = 2 to 6 can be, depending on which tris-chloroalkylphosphot one starts out. The alkane-diphosphonic acids nm η = 2 to 4 can be prepared particularly advantageously in this way
In addition to the straight-chain chloroalkyl phosphites, the corresponding branched-chain chloroalkyl phosphites are also capable of reacting with phenyl phosphite.
When implementing it, it is important to ensure that the xo tris-chloroalkyl phosphite, which z. B. from PCl ₃ and alkylene oxide is obtained, free of Vea · -iungen with PC groups, otherwise iänden under \ during the reaction could form phosphines explosive. The tetraphenyl esters can be prepared by heating with the required amount of aqueous sodium hydroxide solution to be saponified. The free diphosphonic acid is obtained from the sodium salts by saturation with hydrogen chloride, whereby the sodium chloride is deposited almost completely or can be removed via cation exchangers. In the technical preparation of alkane-diphosphonic acids the hydrogen chloride produced during phosphite production can be used to obtain it The present invention relates to a process for the preparation of α, ω-alkane-diphosphonic acids. alternate Usually, the alkanediphosphonic acids 25 of the free diphosphonic acids from the ester are used • from the tetraethyl esters of the corresponding acids. won. Mainly two methods are used to prepare these esters one after the Michaelis-Arbusow reaction «, co-dihaloalkanes with trialkyl phosphite or after the Michaelis-Becker reaction converts dihaloalkanes with AUcalidialkylphosphites. Both reactions are only suitable for the preparation of alkanediphosphonic acids, which are derived from hydrocarbons with at least 3 carbon atoms. Ethane diphosphonic Acid is only produced in moderate yields, while methane-diphosphonic acid is produced according to the Michaelis-Becker reaction cannot be produced at all. Chloromethylphosphonate can be used to produce methane or ethane diphosphonic acids Another way of producing the free acid from the phenyl ester is to treat it with hydrochloric acid at 150 ^° C. in pressure vessels.