METHOD FOR PREPARING PHOSPHINE COMPOUND BASED ON PYROPHOSPHOROUS ACID
20250163085 ยท 2025-05-22
Inventors
Cpc classification
C07F9/5081
CHEMISTRY; METALLURGY
International classification
Abstract
A method for preparing a phosphine compound using pyrophosphorous acid is provided. A phosphine oxide compound or a phosphine sulfide compound is reacted with reducing agent pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) with or without impurities under stirring in the presence of a catalyst to produce a reaction product, where the catalyst is elementary halogen (X.sub.2) or halide (M.sub.XX.sub.Y). After the reaction is completed, the reaction product is subjected to water washing, extraction and purification to obtain the target phosphine compound.
Claims
1. A method for preparing a phosphine compound based on pyrophosphorous acid, comprising: adding pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) with or without impurities as a reducing agent to a phosphine oxide compound or a phosphine sulfide compound to obtain a mixture; mixing the mixture with a catalyst followed by a reduction reaction under stirring to produce a reaction product, wherein the catalyst is an elementary halogen X.sub.2 or a halide M.sub.XX.sub.Y; and subjecting the reaction product to water washing, extraction and purification to obtain the phosphine compound Y; wherein a molar ratio of pyrophosphorous acid to a phosphine oxide group in phosphine oxide compound or a phosphine sulfide group in the phosphine sulfide compound is 1-20:1; and a molar ratio of the catalyst to the phosphine oxide group in the phosphine oxide compound or the phosphine sulfide group in the phosphine sulfide compound is 0.001-0.1:1.
2. The method of claim 1, wherein the elementary halogen X.sub.2 is selected from the group consisting of Cl.sub.2, Br.sub.2 and I.sub.2; and the halide M.sub.XX.sub.Y is an organic or inorganic halide free of fluorine.
3. The method of claim 1, wherein the elementary halogen X.sub.2 is I.sub.2, and the halide M.sub.XX.sub.Y is an iodide compound.
4. The method of claim 1, wherein the phosphine oxide compound contains an aromatic group, and the phosphine sulfide compound contains an aromatic group.
5. The method of claim 1, wherein the phosphine oxide compound and the phosphine sulfide compound are each represented by, ##STR00037## the phosphine compound Y is correspondingly represented by ##STR00038## and a reaction scheme is correspondingly shown as ##STR00039## wherein Z is O or S; R.sup.1 and R.sup.2 are each an aryl group; and R.sup.3 is selected from the group consisting of cycloalkyl, alkyl, thiophenyl, ferrocenyl, and aryl; and R.sup.4 is selected from the group consisting of aryl, ferrocenyl and alkyl.
6. The method of claim 5, wherein R.sup.1 and R.sup.2 are each independently an unsubstituted phenyl, or a phenyl substituted with halogen, alkoxy, trifluoromethyl, cyano, alkyl, or a combination thereof; R.sup.3 is an unsubstituted phenyl, thiophenyl, ferrocenyl, cycloalkyl, an unsubstituted alkyl, a phenyl substituted with halogen, alkoxy, trifluoromethyl, cyano, alkyl, a high-molecular group or a combination thereof, or an alkyl substituted with phenyl or a high-molecular group; and R.sup.4 is selected from the group consisting of phenyl, ferrocenyl and alkyl.
7. The method of claim 1, wherein for the pyrophosphorous acid with impurities, the impurities comprise carboxylic acid, acyl chloride, phosphorous acid, water, hydrogen chloride, or a combination thereof; and the impurities account for 20% or less of a total weight of the pyrophosphorous acid.
8. The method of claim 1, wherein the reduction reaction is carried out under a nitrogen atmosphere or an air atmosphere.
9. The method of claim 1, further comprising: adding an organic solvent; wherein the organic solvent is selected from the group consisting of an aromatic solvent, alkane, haloalkane, and a combination thereof.
10. The method of claim 1, wherein the molar ratio of the catalyst to the phosphine oxide group in the phosphine oxide compound or the phosphine sulfide group in the phosphine sulfide compound is 0.0025-0.025:1.
Description
DETAILED DESCRIPTION OF EMBODIMENTS
[0050] The technical solutions of the present disclosure will be described clearly and completely below in conjunction with the embodiments. It is obvious that the described embodiments are merely some embodiments of the present disclosure, instead of all embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without making creative effort shall fall within the scope of the present disclosure.
Experimental Example 1
Synthesis of Pyrophosphorous Acid (H.sub.4P.sub.2O.sub.5)
[0051] Phosphorous acid (410 g, 5 mol, 5 equiv.) was added to a three-neck flask under a nitrogen atmosphere, to which phosphorus trichloride (PCl.sub.3, 137.3 g, 1 mmol, 1 equiv.) was added dropwise at 0 C. The reaction mixture was restored to room temperature and reacted overnight. After the reaction was completed, the reaction mixture was subjected to vacuum distillation to remove low-boiling point substances, so as to produce a yellow solid pyrophosphorous acid (H.sub.4P.sub.2O.sub.5, 350.3 g, 2.4 mol, 96% yield, 99% purity as determined by .sup.31P NMR and .sup.1H NMR).
Example 1
Preparation of Triphenylphosphine (Ph.SUB.3.P)
[0052] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2, 22.8 mg, 0.09 mmol, 0.025 equiv.), pyrophosphorous acid (H.sub.4P.sub.2O.sub.5, 5.26 g, 35.9 mmol, 10 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. After the reaction was completed, the reaction mixture was added with water (5 mL), and subjected to extraction with ethyl acetate. An organic phase was collected, concentrated and purified by silica gel column chromatography under a nitrogen atmosphere to produce triphenylphosphine (Ph.sub.3P, 867.7 mg, 3.3 mmol, 99.5% purity analyzed by gas chromatography (GC) and 92% yield).
Examples 2-24
[0053] Based on Example 1, the solvent (without solvent or with different solvents), catalyst (iodine (I.sub.2) or hydrogen iodide (HI)), the solvent volume (mL), the molar ratio of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) to triphenylphosphine oxide (Ph.sub.3P(O)), the molar ratio of iodine (I.sub.2) to triphenylphosphine oxide (Ph.sub.3P(O)), the reaction temperature and the reaction time were adjusted to obtain various triphenylphosphine (Ph.sub.3P) samples 2-24.
[0054] The reaction conditions of Examples 1-24 were shown in Table 1.
TABLE-US-00001 TABLE 1 Reaction conditions and triphenylphosphine (Ph.sub.3P) yields of Examples 1-24
[0055] It can be concluded from the comparison between Example 1 and Examples 2-3 that under the same conditions, the reaction was essentially complete after 5 h, and extending the reaction time will not significantly increase the yield after 5 h.
[0056] It can be concluded from the comparison between Example 1 and Examples 4-5 under the same conditions, 100 C. was the optimal reaction temperature, and lowering or further increasing the temperature will not increase the yield.
[0057] The comparison between Example 1 and Examples 6-9 showed that under the same conditions, continuously reducing the amount of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) led to a decrease in the reaction yield. In the case of 1.3 equivalents of H.sub.4P.sub.2O.sub.5 were used, only 11% of triphenylphosphine (Ph.sub.3P) was reduced. Increasing the amount of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) from 10 equivalents to 15 equivalents did not further improve the yield; instead, it decreased from 92% to 90%. Therefore, it could be concluded that for the reduction reaction of phosphine oxide (sulfur) compounds in the H.sub.4P.sub.2O.sub.5/I.sub.2 system, the molar ratio of H.sub.4P.sub.2O.sub.5 to phosphine oxide (sulfur) compounds should be between 1-20:1, with a preferred ratio of 8-15:1. Considering economic cost factors, the most optimal molar ratio is 8-10:1.
[0058] The comparison between Example 1 and Examples 10-13 showed that under the same conditions, as demonstrated in Example 10, increasing the amount of iodine (I.sub.2) as a catalyst actually decreased the reaction yield. As seen in Example 11, when the iodine (I.sub.2) amount was reduced to 0.0055 mol %, the yield increased to 94%, which was higher than the result in Example 1 where 0.025 mol % iodine was used, indicating that a moderate reduction in iodine amount was more beneficial for the reduction reaction. As shown in Example 13, when the iodine (I.sub.2) amount was further reduced to 0.0025 mol %, a high yield of 91% was still maintained. Therefore, it could be concluded that for the reduction reaction of phosphine oxide (sulfur) compounds in the H.sub.4P.sub.2O.sub.5/I.sub.2 system, the molar ratio of iodine (I.sub.2) to phosphine oxide (sulfur) compounds should be between 0.001-0.1:1, with a preferred ratio of 0.0025-0.025:1.
[0059] The comparison between Example 1 and Examples 14-15 showed that under the same reaction conditions, the reaction failed to proceed without the addition of iodine (I.sub.2) as the catalyst, nor did it proceed when hydrogen iodide (HI) was used as a substitute for iodine (I.sub.2).
[0060] The comparison between Example 1 and Example 16 showed that under the same reaction conditions, the reaction can proceed efficiently even without the addition of a solvent, achieving a yield of 91% for triphenylphosphine (Ph.sub.3P).
[0061] The comparison between Example 1 and Examples 17-18 showed that under the same reaction conditions, polar solvents, such as ethanol and THE, will hinder the reaction from occurring.
[0062] The comparison between Example 1 and Examples 19-21 demonstrated that under the same reaction conditions, the reaction can also proceed in a non-polar hydrocarbon solvent such as xylene, mesitylene, and n-hexane.
Example 25
Preparation of Triphenylphosphine (Ph.SUB.3.P) Under an Air Atmosphere
[0063] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2) (22.8 mg, 0.09 mmol, 0.025 equiv.), pyrophosphorous acid (H.sub.4P.sub.2O.sub.5, 5.26 g, 35.9 mmol, 10 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under an air atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. After the reaction was completed, the reaction mixture was added with water (5 mL), and subjected to extraction with ethyl acetate. The organic phase was collected, concentrated and purified by silica gel column chromatography under a nitrogen atmosphere to produce triphenylphosphine (Ph.sub.3P, 783.7 mg, 2.99 mmol, 99.5% GC content and 83% yield).
[0064] The comparison between Example 1 and Example 25 showed that triphenylphosphine oxide (Ph.sub.3P(O)) can participate in the reduction reaction of the H.sub.4P.sub.2O.sub.5/I.sub.2 system under both air and nitrogen atmospheres, without significant loss in yield. However, it was observed that triphenylphosphine oxide (Ph.sub.3P(O)) had a higher yield under an oxygen-free condition than under an air atmosphere. Therefore, it could be concluded that the reduction reaction of phosphine oxide (sulfur) compounds in the H.sub.4P.sub.2O.sub.5/I.sub.2 system could proceed under both air and nitrogen atmosphere (under oxygen or oxygen-free conditions).
Example 26
Preparation of Triphenylphosphine (Ph.sub.3P) Based on a Mixture of Pyrophosphorous Acid (H.sub.4P.sub.2O.sub.5) Containing Impurities
[0065] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2) (22.8 mg, 0.09 mmol, 0.025 equiv.), a mixture of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5, 5.3 g, containing 80 wt. % H.sub.4P.sub.2O.sub.5, 15 wt. % H.sub.3PO.sub.3, 1 wt. % i-BuCO.sub.2H, 3 wt. % i-BuCOCl, 0.5 wt. % HCl and 0.5 wt. % unidentified substances) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. After the reaction was completed, the reaction mixture was added with water (5 mL), and subjected to extraction with ethyl acetate. The organic phase was collected, concentrated and purified by silica gel column chromatography under a nitrogen atmosphere to produce triphenylphosphine (Ph.sub.3P, 848.3 mg, 3.2 mmol, 99.5% GC content and 90% yield).
[0066] The comparison between Example 1 and Example 26 showed that using the mixture of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) containing impurities to prepare triphenylphosphine (Ph.sub.3P) resulted in a yield of 90%. This indicated that the waste phosphoric acid byproduct (containing 80 wt. % pyrophosphorous acid and 8 equiv. of effective pyrophosphorous acid) obtained from the industrial preparation of isobutyryl chloride using isobutyric acid and PCl.sub.3 can be used in this reduction catalytic reaction to achieve a high yield of the triphenylphosphine product.
Examples 27-34
Reduction Reactions of Different Phosphine Oxide and Phosphine Sulfide Compounds in the H.sub.4P.sub.2O.sub.5/I.sub.2 System
[0067] Based on the optimal Example 11 in Examples 1-24, 1 g of different phosphine oxide and phosphine sulfide compounds were separately selected and reacted with 0.0055 mol % iodine (I.sub.2), 10 equivalents of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) and 5 mL of toluene at 100 C. for 5 h to obtain the corresponding phosphine compounds.
[0068] The reactions of Example 11 and Examples 27-34 were shown in Table 2.
TABLE-US-00002 TABLE 2 Reactions of different phosphine oxide (sulfide) compounds in the H.sub.4P.sub.2O.sub.5/I.sub.2 system
[0069] Through Example 11, Examples 27-29 and Examples 31-33, it could be seen that the yields of the different phosphine compound products were all above 85%.
[0070] It can be concluded from the comparison between Example 11 and Examples 27-34 that the phosphine oxide compound contained an aromatic group, and the phosphine sulfide compound contained an aromatic group. Furthermore, the phosphine oxide compound contained the aromatic group bonded to P, and the phosphine sulfide compound contained the aromatic group bonded to P.
[0071] R.sup.1 and R.sup.2 were each an aryl group. R.sup.3 was selected from the group consisting of cycloalkyl, alkyl, thiophenyl, ferrocenyl, and aryl. R.sup.4 was selected from the group consisting of aryl, ferrocenyl and alkyl. R.sup.1, R.sup.2 and R.sup.3 can be the same or independently different.
[0072] Furthermore, R.sup.1 and R.sup.2 were each independently an unsubstituted phenyl, or a phenyl substituted with halogen, alkoxy, trifluoromethyl, cyano, alkyl, or a combination thereof. R.sup.3 was an unsubstituted phenyl, thiophenyl, ferrocenyl, cycloalkyl, an unsubstituted alkyl, a phenyl substituted with halogen, alkoxy, trifluoromethyl, cyano, alkyl or a combination thereof, or an alkyl substituted with phenyl. R.sup.4 was selected from the group consisting of phenyl, ferrocenyl and alkyl.
[0073] Based on Examples 1 and 27-34, it can be inferred that Z can be O or S. Therefore, it could be further speculated that both phosphine oxide and phosphine sulfide compounds can produce the phosphine compounds by reduction in the H.sub.4P.sub.2O.sub.5/I.sub.2 system.
Examples 35-38
Reduction Reactions of Various Phosphine Oxide Compounds Containing Multiple Phosphine Oxide Bonds in the H.sub.4P.sub.2O.sub.5/I.sub.2 System
[0074] Based on the optimal Example 11, 1 g of various phosphine oxide compounds containing multiple phosphine oxide bonds and phosphine sulfide compounds were separately selected and reacted with 0.0055 mol % iodine (I.sub.2), 10 equivalents of pyrophosphorous acid (H.sub.4P.sub.2O.sub.5) and 5 mL of toluene at 100 C. for 5 h to obtain the corresponding phosphine compounds.
[0075] The reactions of Examples 35-38 were shown in Table 3.
TABLE-US-00003 TABLE 3 Reactions of compounds containing multiple phosphine oxide bonds in the H.sub.4P.sub.2O.sub.5/I.sub.2 system
[0076] From Examples 35-38, it can be observed that compounds containing two phosphine oxide bonds reacted in the H.sub.4P.sub.2O.sub.5/I.sub.2 system with yields above 97%. Therefore, it could be concluded that phosphine oxide compounds with multiple phosphine oxide groups can react in the H.sub.4P.sub.2O.sub.5/I.sub.2 system and achieve good yields.
Examples 39-41
[0077] Based on Example 1, 0.18 mmol of different halides (M.sub.XX.sub.Y) were selected as catalysts and reacted under the same conditions as in Example 1 to produce various triphenylphosphine (Ph.sub.3P) samples 39-41.
[0078] The reaction conditions for Examples 39-41 were shown in Table 4.
TABLE-US-00004 TABLE 4 Reaction conditions and triphenylphosphine (Ph.sub.3P) yields of Examples 39-41 Molar ratio of Reaction H.sub.4P.sub.2O.sub.5 to Amount of temperature Reaction Example Solvent Ph.sub.3P(O) Catalyst catalyst ( C.) time (h) Yield 39 5 mL of 10 Me.sub.3SiI 0.18 mmol 100 5 98% toluene 40 5 mL of 10 NaI 0.18 mmol 100 5 95% toluene 41 5 mL of 10 NaBr 0.18 mmol 100 5 3% toluene
[0079] It could be seen from Examples 39-41 that halide (M.sub.XX.sub.Y) as the catalyst enabled the preparation of phosphine compounds.
[0080] From Example 41, it was observed that non-iodide catalysts can still facilitate the preparation of phosphine compounds, although the yield was only 3%. Therefore, iodide compounds were preferred catalysts for the preparation of phosphine compounds.
Comparative Example 1
Preparation of Triphenylphosphine (Ph.sub.3P) Based on Phosphorous Acid (H.sub.3PO.sub.3)
[0081] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2, 22.8 mg, 0.09 mmol, 0.025 equiv.), phosphorous acid (H.sub.3PO.sub.3, 5.9 g, 71.87 mmol, 10 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. No reaction was observed, and the yield was 0%.
Comparative Example 2
Preparation of Triphenylphosphine (Ph.sub.3P) Based on Phosphorous Acid (H.sub.3PO.sub.3)
[0082] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2, 22.8 mg, 0.09 mmol, 0.025 equiv.), phosphorous acid (H.sub.3PO.sub.3, 5.9 g, 71.87 mmol, 20 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 120 C. and reacted at 120 C. for 10 h. No reaction was observed, and the yield was 0%.
Comparative Example 3
Preparation of Triphenylphosphine (Ph.sub.3P) Based on Hypophosphorous Acid (H.sub.3PO.sub.2)
[0083] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2, 22.8 mg, 0.09 mmol, 0.025 equiv.), hypophosphorous acid (H.sub.3PO.sub.2, 4.74 g, 71.87 mmol, 20 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. No reaction was observed, and the yield was 0%.
Comparative Example 4
Preparation of Triphenylphosphine (Ph.sub.3P) Based on Metaphosphoric Acid (HPO.sub.3)
[0084] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), iodine (I.sub.2, 22.8 mg, 0.09 mmol, 0.025 equiv.), metaphosphoric acid (HPO.sub.3, 3.59 g, 71.87 mmol, 20 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. No reaction was observed, and the yield was 0%.
[0085] The comparison between Examples 1-38 and Comparative Examples 14 showed that reducing agents such as phosphorous acid, hypophosphorous acid or metaphosphoric acid failed to catalyze the reaction of triphenylphosphine oxide (Ph.sub.3P(O)).
Comparative Example 5
Preparation of Triphenylphosphine (Ph.SUB.3.P) in the Absence of a Catalyst
[0086] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), pyrophosphorous acid (H.sub.4P.sub.2O.sub.5, 5.26 g, 35.9 mmol, 10 equiv.), and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. After the reaction was completed, the reaction mixture was added with water (5 mL), and subjected to extraction with ethyl acetate. The organic phase was collected, concentrated and purified by silica gel column chromatography under a nitrogen atmosphere to obtain triphenylphosphine (Ph.sub.3P). The yield of the triphenylphosphine (Ph.sub.3P) was less than 1%.
[0087] The comparison between Example 1 and Comparative Example 5 showed that without the addition of the elementary halogen (X.sub.2) or halide (M.sub.XX.sub.Y), triphenylphosphine (Ph.sub.3P) could not be effectively obtained.
Comparative Example 6
Preparation of Triphenylphosphine (Ph.SUB.3.P) Using Sodium Fluoride as a Catalyst
[0088] Triphenylphosphine oxide (Ph.sub.3P(O), 1.0 g, 3.59 mmol, 1 equiv.), sodium fluoride (NaF, 0.19 mmol, 7.6 mg), pyrophosphorous acid (H.sub.4P.sub.2O.sub.5, 5.26 g, 35.9 mmol, 10 equiv.) and toluene (5.0 mL) were added to a 50 mL Schlenk flask under a nitrogen atmosphere. The reaction mixture was heated to 100 C. and reacted at 100 C. for 5 h. No reaction was observed, and the yield was 0%.
[0089] It could be seen from Comparative Example 6 that fluorine or fluorides failed to catalyze the reaction of triphenylphosphine oxide (Ph.sub.3P(O)).