SE424639B - PUT TO MAKE PHOSPHORUS ESTERS - Google Patents

Description

m. .M 7602715-0 2 Houben-Weyl, Nbthoden der Organischen Chemie, volume 12/1, G. Thieme ~ Ver- lag (Stuttgart) 1963, sid; 320 - 323, and G.M. Kosolapoff and L.

Maier, Organic Phosphorus Compounds, Volume 4, Wiley ~ Interscience (New York) 1972. ii The diester of the alkane or arylphosphonic acid can, according to previous works, be prepared according to formula 3): K i to II 3) 'i '12 -P (o) c12 + i 2 R'oH ---> RP (oR ') 2 + 2' Hcl Honben-Weyl, Methods of Organic Chemistry, volume 12/1, G.Thieme-Ver- lag (Stuttgart) 1963, p. 423 - 430. The ester of dialkyl-, diaryl- or aryl-alkyl-phosphinic acids can be obtained by reacting the corresponding acid chlorides with alcohols according to formula 4):> 7 4) R2P (o) _c1 + R'ogH-g -> R2P (o) o12¿ g + Hcl Houben-Weylg Methods of Organic Chemistry, volume 12/1, G.Thieme-Vvr- lagg (Stuttgart) 1963, sia. 248 - 249, and a. Kosolapoff and x fl maier, Organie Phosphorns Compounds, volume 6, Wiley-Interscience (New York) 1973.

The phosphorus-containing ester is prepared in the prior art, preferably in reactions starting from PCl3 and R-PCI2, at low temperatures and usually in the presence of bases for binding the hydrogen chloride formed. Ammonia or organic nitrogen bases, such as amines or pyridine, were used as bases. Likewise, it is also common to use inert solvents in the cases previously described. The continued production process necessitates filtration of base hydrochloride, after which the phosphorus-containing ester can be recovered, usually by distillation, after the inert solvent has first been removed. The work at low temperatures of -30 - + 20 ° C, the use of inert solvents, the use of bases to bind the hydrogen chloride and the necessity to filter off the base hydrochloride from the reaction mixture make the previously known manufacturing methods for phosphorus-containing esters expensive and cumbersome.

The invention, on the other hand, relates to a process for preparing phosphorus-containing esters of the general formula 7602715-0 wherein X represents an alkyl group having 1 to 3 carbon atoms, Y represents an alkoxy group having 3 to 6 carbon atoms, Y represents an alkoxy group having 3 to 6 carbon atoms and Z represents a hydrogen atom. or an alkyl group having 1 to 3 carbon atoms, by reaction of phosphorus halogen compounds of the general formula BI AP “C | D wherein A and B independently represent a chlorine or bromine atom or an alkyl group having 1-3 carbon atoms, C a chlorine or bromine atom and D a free electron pair or an oxygen atom, with aliphatic alcohols having 3 to 6 carbon atoms.

The process according to the invention is characterized by mixing phosphorus halide compounds and the aliphatic alcohol, both in liquid form, by reacting in an unheated reaction zone and then adding the reaction mixture at the top of a steam-heated filler column, the bottom of which inert gas is introduced into countercurrent , hydrogen halide, excess alcohol and optionally alkyl halide together with the inert gas distilling off at the top, partially condensing and withdrawing, while the phosphorus-containing ester, optionally in admixture with excess alcohol, flows through the column downwards and is withdrawn there.

The process according to the invention can furthermore preferably be characterized in that a) a phosphorus halogen compound solid at room temperature is heated to a few degrees above the melting point and used in a melt-liquid form, b) 1.2 to 6 times the stoichiometrically required amount of alcohol is used per mole of phosphorus halogen compound, c) in the reaction zone initiates 1 - 10 liters of nitrogen per liter of reaction mixture and hour, d) at the bottom of the filler column begins 50 - 250 liters of nitrogen gas per liter of reaction mixture and hour as inert gas.

As phosphorus halogen compounds, e.g. fosfortriklo- chloride, metyldiklorfosfin, etyldiklorfosfin, propyldiklorfosfin, phenyl dichlorophosphine, metanfosfonsyradiklorid, etanfosfonsyradiklorid, propan fosfonsyradiklorid, phenylphosphonic dichloride, dimetylfosfinsyradiklorid, _, o 76o271s + 4 dietylfosfinsyraklorid, dipropylfosfinsyraklorid, methyl ethyl phosphinic acid chloride, metylpropylfosfinsyraklorid, etylpropylfosfinsyraklorid, and diphenylphosphinic the corresponding bromides.

As alcohols, for example, n-propanol, i-propanol, n-butanol, i-butanol, etc. are used, preferably, however, i-butanol, and the alcohols should contain less than 0.5% by weight, preferably less than 0.1% by weight. water. The reaction is conveniently carried out by adding the phosphorus halogen compound present at room temperature, 18 to 30 ° C or heated to a few degrees above the melting point above room temperature, together with the aliphatic alcohol present at room temperature to a mixing device. , which simultaneously acts as a reaction zone. The mixture is heated by itself through the liberated heat of reaction, but without starting to boil. The reaction zone can be cooled with water from outside, but this is usually not necessary. The reaction mixture is instead usually passed without prior dissipation of the heat of reaction to the top of the separation column filled with filler bodies, the halogen hydrogen formed with a part of the excess alcohol and with any alkyl halide formed being distilled off through the countercurrent nitrogen gas, and separated in a subsequent condensation and absorption device.

The phosphorus-containing ester passes through the separation column with a portion of the excess alcohol and is continuously withdrawn at the bottom of the column.

The reaction products are processed in the traditional way. The phosphorus-containing ester can be freed from excess aliphatic alcohol by distillation, possibly after prior neutralization of the solution. The distillate of hydrogen halide, aliphatic alcohol and optionally alkyl halide are likewise separated in the usual way, so that the alcohol is recovered. In the process according to the invention, a decomposition of the formed phosphorus-containing ester by the formed hydrogen halide is surprisingly largely avoided, as this is later separated already in the top part of the separation column by the countercurrent nitrogen gas, whereby the contact time with the phosphorus-containing ester is greatly reduced.

The process according to the invention has a number of advantages over the traditional process: The phosphorus-containing ester formed is separated very quickly from the halogen hydrogen formed simultaneously in a manner characteristic of the invention, and consequently the decomposition of the phosphorus-containing ester catalyzed by the halogen hydrogen decreases. @ 2fi1; - @ Un for improved exchanges. In the previous process, bases, such as ammonia or organic amines, were used to bind all the hydrogen halide formed in the form of ammonium or amine hydrohalide salts, which precipitated and had to be filtered off with large losses. However, some of the base hydrohalides remained loose and resulted in catalytic decomposition of the phosphorus-containing ester and thus a reduction in yield. These disadvantages do not exist in the method according to the invention. The phosphorus-containing esters are obtained in concentrated form as in the previous methods.

In the stepwise reaction between phosphorus halogen compounds and aliphatic alcohols according to the prior art, the heat from the exothermic reactions is first dissipated through the wall of the reaction vessel, and only then can the equally strongly exothermic neutralization of the halogen hydrogen remaining in the solution take place, again in a continuous thickening. , liquid medium due to the precipitating solid base hydrohalide, the heat must be dissipated through the wall of the reaction vessel. In addition, according to the older procedure, e.g. When using ammonia as a base and a chlorine-containing phosphorus compound, it is necessary to stir the precipitating microcrystalline ammonium chloride for a few hours in the reaction medium, so that the salt changes to a filterable form by recrystallization.

In the technical embodiment of the method according to the invention, the size of the apparatus plays only an insignificant role, as an uninterrupted flow of outlet and end products passes through the reaction zone, while the traditional, stepwise manufacturing method with respect to space-time yield was limited by the reaction vessel's cooling surface and dependence. on the size of the filtration devices for the base hydrohalide became very expensive.

Phosphorus-containing esters with P-H bonds are valuable starting materials for flame retardants for polyesters, polyurethanes, and polyacrylonitrile. Due to their high purity, they are particularly suitable as reactants in reactions catalyzed by radical scavengers.

Example 1 Methanephosphonic acid monoisobutyl ester, compare formula 2).

In the apparatus shown in the drawing, 1,288 g, 3.88 mol, isobutanol and from the storage tank 2,215 g, 1.84 mol, methyl dichlorophosphine were charged for 3.5 hours at room temperature from the storage tank while simultaneously introducing 5 l / h of nitrogen gas. in the reaction vessel 3.

The reaction mixture was then passed to the top of the separation column 4 heated with water vapor to 10000. was taken through line 5 of the blown product and collected, and gas chromatographic analysis showed an amount of 228 g, 1.67 mol, of methanephosphonic acid monoisobutyl ester, corresponding to 91% of the theoretical yield. In a distillate withdrawn and collected through line 7 and in the HCl absorption (not shown) connected to line 8, a total of 1.80 moles of hydrogen chloride were found by titration, 98% of theory. The nitrogen gas used was eliminated by the HCl absorption.

.ExemEel_2 'Methanephosphonic acid ~ monoisobutyl ester, compare formula 2); In the same manner as in Example 1, 640 g, 8.63 moles of isobutanol were reacted with 229 g, 1.96 moles, of methyl dichlorophosphine. According to gas chromatographic analysis, 265 g, 1.95 mol, of methane phosphonic acid monoisobutyl ester were present in the blow product, corresponding to 99% of the theoretical amount. In the distillate and in the HCl absorption, a total of 1.96 moles of hydrogen chloride were detected, 100% of the theoretical amount.

* Example gel 3 Methanephosphonic acid monoisobutyl ester, compare formula 2).

In the same manner as in Example 1, 464 g, 6.26 moles of isobutanol were reacted with 118 g, 1.01 moles, of methyl dichlorophosphine. From the gas chromatographic analysis, a content of 135 g, 0.99 mol, of methanephosphonic acid monoiso-hutyl ester corresponding to 98% of the theoretical yield was calculated for the blown product. Blowing product: acid number was 2.0 mg KOH / g. g * In the distillate and in the HCl absorption, a total of 1.00 moles of hydrogen chloride were detected, 99% of the theoretical yield.

Example 4 Comparative example.

During the introduction of nitrogen, 88.8 g, 1.2 mol, i-butanol and 50.5 g were added dropwise to a solution of 58.5 g, 0.5 mol, of methyl dichlorophosphine in 300 ml of anhydrous ether with stirring and cooling. 0.5 mol, triethylamine in 100 ml of anhydrous ether. Then 0.5 h was heated at 35 ° C under reflux, after which the mixture was cooled to 5 ° C and filtered. The filtrate was evaporated and vacuum distilled in a nitrogen atmosphere. The excess i-butanol and i-butyl chloride were taken out during the process.

The main product was 59.8 g, 0.44 mol, of methanephosphonic acid monoisobutyl ester, 88% of theory.

Exeggel 5 Comparative example. Into a reaction flask was charged 2220 g, 30 moles, of isobutanol, and with stirring, introduction of nitrogen and cooling to below 2000, 585 g, 5 moles, of methyldichlorophosphine were dropped over 2 hours.

It was then neutralized with gaseous ammonia while cooling to below 30 ° C and stirring for 3 hours. The mixture was then stirred at room temperature for about 8 hours to recrystallize from ammonium. The filter cake was washed twice with 200 g of i-butanol each time. In the filtrate of 3220 g, according to gas chromatographic analysis, 19.2%, 615 g = 4.52 mol, methanephosphonic acid monoisobutyl ester were present, 90.5% of the theoretical yield. the chloride, which is then filtered off.

Example 6 Diisobutyl phosphite, compare formula 1).

In the same manner as in Example 1, 400 g, 5.40 mol, of isobutanol were reacted with 191 g, 1.39 mol, of phosphorus (III) chloride.

According to gas chromatographic analysis, the blow product contained 255 g, 1.31 mol, of diisobutyl phosphite, corresponding to 94% of the theoretical yield.

The acid value of the blown product was 2.4 mg KOH / g.

In the distillate and in the HCl absorption, a total of 2.78 moles of hydrogen chloride were detected, 100% of the theoretical yield.

Example 7 Methanephosphonic acid diisobutyl ester, compare formula 3).

In the same manner as in Example 1, 424 g, 5.72 moles of isobutanol were reacted with 168 g, 1.26 moles of methanephosphonic acid dichloride, which was added from the storage vessel heated to 45 ° C. 2 According to gas chromatographic analysis, the blowing product contained 250 g, 1 , 20 moles in liquid form. methanephosphonic acid diisobutyl ester, corresponding to 95% of theory. The acid number of the blown product was determined to be 7.8 mg KOH / g. In the distillate and in the HCl absorption, a hydrogen chloride content of 2.44 mol, 97% of the theoretical yield, was found.

Example 8 Methanephosphonic acid diisobutyl ester, compare formula 3).

In the same manner as in Example 7, 640 g, 8.63 moles of isobutanol were reacted with 189 g, 1.42 moles, of methanephosphonic acid dichloride.

According to gas chromatographic analysis, the blow product contained 291 g, 1.40 mol, of methanephosphonic acid diisobutyl ester, corresponding to 99% of theory. The acid value of the blown product was 5.5 mg KOH / g.

In the allowed and in the HCl absorption, a total of 2.86 moles of hydrogen chloride, 100% of theory, were found by titration.

Example 9 Dimethylphosphinic acid isobutyl ester, compare formula 4).

In the same manner as in Example 1, 600 g, 8.09 moles of isobutanol were reacted with 159 g, 1.41 moles, of dimethylphosphinic acid chloride, which was added in liquid five from the heated crucible 2.

According to gas chromatographic analysis, 192 g, 1.28 mol, of dimethylphosphinic acid isobutyl ester were present in the blown product, corresponding to 91% theoretical yield.

The distillate and the HCl absorption contained a total of 1.08 moles of hydrogen chloride, 76% of theory. a hydrogen chloride content of 0.12 mol could be calculated for the blown product.

From the chloride determination and acid tali

Claims (5)

7602715-0 Eatentkrav A process for the preparation of phosphorus-containing esters of the general formula O II XEZ a Y wherein X represents an alkyl group having 4-3 carbon atoms, or an alkoxy group having 5-6 carbon atoms, Y an alkoxy group having 5-C carbon atoms, and Z a hydrogen atom or an alkyl group having 4-E carbon atoms, by reacting phosphorus halogen compounds of the general formula T v Ej * Tin-w CJ wherein A and B each independently represent a chlorine or bromine atom or an alkyl group having 1-5 carbon atoms C a chlorine or bromine atom, and D a free electron pair or an oxygen atom, with aliphatic alcohols having 5 to 6 carbon atoms, characterized by bringing phosphorus halogen phasing and the aliphatic alcohol, both in liquid form, to react by mixing in an unheated reaction zone, and then add the reaction mixture to the top of a steam-heated filler column, at the bottom of which inert gas is introduced into countercurrent, halogenated hydrogen, excess alcohol and, if appropriate, halide together with inert gas one de-distillates via the top, partially condenses and is taken out, while the phosphorus-containing ester, possibly in admixture with excess alcohol, flows through the downward column and is taken out there. 2. A method according to claim 1, characterized in that a phosphorus halogen compound solid at room temperature is heated to a few degrees above the melting point and used in melt-liquid form. 3. A method according to claim 4 or 2, characterized in that 1.2-6 times the stoichiometrically required amount of alcohol per mole of phosphorus halide compound is used. vsdšviísištó i 1¿, 4. A method according to any one of the preceding claims, characterized in that 1-10 l of nitrogen gas per liter of reaction mixture is introduced into the reaction zone per liter of reaction mixture per hour. 5. A method according to any one of the preceding claims, characterized in that 50-250 l of nitrogen gas per liter of reaction mixture and hour as inert gas are introduced at the bottom of the filler column. 'ANFzsRDA PusLIKATwNER; n: 54-1 145 us 2 692 sen, s 494 asea v A