Method for obtaining 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane

Abstract

FIELD: organic chemistry; chemical technology.SUBSTANCE: invention relates to method for producing 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (5). The method involves the interaction of glycidol (1) and 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (4) in a molar ratio of 2:1 in dichloromethane for 60-90 minutes at room temperature, followed by evaporation of the solvent, filtration from triethylamine hydrochloride and maintaining the reaction product in a membrane pump vacuum at room temperature.EFFECT: resulting compound is a reactive fire retardant and can be used to create epoxy materials with non-flammable properties.2 cl, 2 ex

Description

[0001] The invention relates to the field of organic chemistry, specifically to a method for producing 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane, a reactive fire retardant for creating epoxy materials with non-flammable properties.

[0002] A compound with a similar structure, but containing phosphorus in the oxidation state of V, as well as its derivatives, were previously obtained and isolated by the authors of the patent [Patent CN 111499663 A PRC. Method for synthesizing nanomaterials / Li Wei, Zhang Hua; application number 202010123456.7; filing date 03 / 15 / 2020; publication date 07 / 24 / 2020. - Text: electronic / / State Intellectual Property Office of the People's Republic of China (CNIPA)]. The patent describes the properties of these compounds as flame retardants for epoxy polymer structures. Examples of the use of phosphorous acid derivatives as fire retardants are also known [Byard B., Wang K., Morgan A., Benin V. New polyether diols as flame retardants for polyurethane: Derivatives of epoxy-functionalized phosphonates and phosphates / / Fire and Materials. - 2018. - Vol. 42, No. 1. - P. 3-17.]. For this reason, 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane is of interest in the same field.

[0003] No method for obtaining 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane is known in the literature; this compound has also not been previously described in the scientific and patent literature, which clearly indicates the scientific novelty of the invention.

[0004] Previously described methods for the isolation and purification of such phosphites with epoxy substituents in the literature often include vacuum distillation, as, for example, in the work [Byard B., Wang K., Morgan A., Benin V. New polyether diols as flame retardants for polyurethane: Derivatives of epoxy-functionalized phosphonates and phosphates / / Fire and Materials. - 2018. - Vol. 42, No. 1. - P. 3-17.], which is a rather labor- and energy-intensive method for purifying compounds, especially those prone to polymerization and decomposition at elevated temperatures.

[0005] It is also worth noting that the methods described in the literature for the preparation of similar phosphites, not necessarily including a pentaerythritol skeleton, obtained from the corresponding phosphorous acid chlorides, often require the use of an inert atmosphere, which complicates the hardware scheme for the synthesis of the target compounds. As described by the authors of the work [Byard B., Wang K., Morgan A., Benin V. New polyether diols as flame retardants for polyurethane: Derivatives of epoxy-functionalized phosphonates and phosphates / / Fire and Materials. - 2018. - Vol. 42, No. 1. - P. 3-17.], the synthesis is carried out in a nitrogen atmosphere.

[0006] The closest to the proposed technical solution is the synthesis of 5,5-dimethyl-2-(oxiran-2-ylmethoxy)-1,3,2-dioxaphosphinane according to the method described by the authors of the work [Byard B., Wang K., Morgan A., Benin V. New polyether diols as flame retardants for polyurethane: Derivatives of epoxy-functionalized phosphonates and phosphates / / Fire and Materials. - 2018. - Vol. 42, No. 1. - P. 3-17.], the method of preparation proposed by the authors is presented in Scheme 1.

[0007]

[0008] Scheme 1. The closest to the technical solution synthesis of 5,5-dimethyl-2-(oxiran-2-ylmethoxy)-1,3,2-dioxaphosphinane from glycidol and 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphinane.

[0009] Preparation method: 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphinane (8.40 g) and triethylamine (5.04 g) were dissolved in tetrahydrofuran (75 ml) in a flask filled with nitrogen. A solution of glycidol (3.69 g) in 15 ml of tetrahydrofuran was added dropwise to the resulting solution. The mixture was stirred at room temperature for 1 hour, then filtered through a glass filter, and the solvent was distilled off under reduced pressure. The resulting colorless oil was distilled under reduced pressure (90-100 °C, 0.1 mmHg) to obtain a high-purity colorless oil (10.12 g, yield 98%).

[0010] The disadvantages of this method are: the need to use an inert gas (nitrogen); the use of a precursor (tetrahydrofuran), the circulation of which in the Russian Federation is limited and for which certain control measures may be exempted, as a solvent; purification of the reaction product by vacuum distillation, which is a labor- and energy-intensive process, and also difficult to carry out for substances containing an epoxy group in their composition, due to the risk of their polymerization and decomposition upon heating.

[0011] The technical result of the invention consists in obtaining 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane with a purity of 98% according to NMR data. The technical result is achieved by adding a solution of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane in dichloromethane to a solution of glycidol with triethylamine in dichloromethane at room temperature, maintaining the reaction mixture for 90 minutes, followed by distillation of the solvent, mixing the resulting substance with methyl tert-butyl ether (MTBE), filtering the precipitate of triethylamine hydrochloride, distilling off the organic solvent and maintaining the resulting liquid in a vacuum membrane pump to get rid of glycidol.

[0012] The proposed production method is illustrated in Scheme 2.

[0013]

[0014] Scheme 2. Proposed method for obtaining 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane.

[0015] The method of obtaining is carried out by the following sequence of operations and modes.

[0016] It is advisable to use glycidol with a purity of at least 98%, 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane with a purity of at least 90% with preliminary filtration from hydrolysis products if present, and triethylamine with a purity of at least 98% as reagents.

[0017] The process should be carried out at a temperature of 20°C to 60°C, for 60–90 minutes, preferably 90 minutes.

[0018] It is recommended to maintain the reaction product in a membrane pump vacuum for 8 hours at room temperature, or wash the substance with IPA and cool the resulting two-phase system, preferably maintaining it in a vacuum.

[0019] A solution of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane in dichloromethane is added to a solution of glycidol and triethylamine in dichloromethane at room temperature using a dropping funnel. The mixture is maintained under stirring, the solvent is evaporated on a rotary evaporator, the resulting mixture is mixed with MTBE, the precipitated triethylamine hydrochloride is filtered off, and the solvent is evaporated on a rotary evaporator. The resulting liquid is maintained at room temperature under a membrane pump vacuum for 8 hours.

[0020] The invention is illustrated by the following examples.

[0021] Example 1.

[0022] Triethylamine (15.4 g, 151 mmol, 2 equiv) was added to a solution of 11.7 g glycidol (151 mmol, 2 equiv) in dichloromethane (60 ml). 9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (75.5 mmol, 10 g) dissolved in 50 ml dichloromethane, pre-filtered from the insoluble part through paper, was added to the resulting mixture through a dropping funnel at room temperature. The reaction mixture was stirred for 1 hour. Then the solvent was evaporated on a rotary evaporator, the resulting mixture was stirred with MTBE for 10 minutes at room temperature, the triethylamine hydrochloride precipitate was filtered off (21.6 g). The solvent was then evaporated to yield 23.4 g of a clear liquid. This was mixed with 100 ml of isopropyl alcohol (IPA). The mixture was then frozen at -20°C until the liquids separated completely. The lower liquid layer was separated, yielding 18.9 g with a 70% NMR content.

[0023] Example 2.

[0024] 11.7 g (151 mmol) of glycidol, 100 ml of dichloromethane and 15.4 g of triethylamine (151 mmol) are placed in a 500 ml round-bottomed single-neck flask. The resulting solution is placed on a magnetic stirrer and cooled with running water using a bath (water temperature ~20 °C). A dropping funnel and a reflux condenser cooled with running water are attached, the outlets of the apparatus to the atmosphere are blocked with calcium chloride tubes to prevent the access of moisture. The starting 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane weighing 20 g (75.5 mmol) is mixed with 100 ml of dichloromethane. With vigorous stirring (400 vol. / min) a solution of the starting 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane is added dropwise to a solution of glycidol with triethylamine at such a rate that the reaction mixture does not boil (absence of visual signs of boiling), the addition is carried out for 30 minutes, the resulting mixture is stirred at room temperature for 1 hour, using TLC analysis in the dichloromethane-hexane system 1:1 note the absence of the starting phosphite chloride in the mixture. After 1 hour and 30 minutes, the reaction mass, which has the form of a suspension, is evaporated to a constant weight at a temperature not exceeding 35 °C. The solvent is distilled off for 1 hour, 200 ml of MTBE are added to the resulting substance and the resulting suspension is stirred on a magnetic stirrer at room temperature for 10 minutes. The separated precipitate of triethylamine hydrochloride is filtered off, the filtrate is collected in a 250 ml round-bottomed flask, and the precipitate on the filter is washed with 100 ml of MTBE.The resulting filtrate is evaporated on a rotary evaporator to a constant mass at a bath temperature no higher than 35 °C, yielding a transparent yellowish liquid weighing 23.1 g. The resulting liquid is maintained in a membrane pump vacuum at room temperature for 8 hours, yielding a wet crystalline white substance weighing 18 g in a flask, which corresponds to a reaction product yield of 70%, the purity of the resulting substance is 98% according to NMR data.

[0025] NMR 31 P (162 MHz, CDCl3, δppm): 130.74 relative to PPh 3.

[0026] NMR 1 H (500 MHz, CDCl3, δ ppm): 4.31 (m, 4H), 4.06 (m, 2H), 3.97 (m, 2H), 3.28 (td, J1=11.31 Hz, J2=1.80 Hz, 2H), 3.16 (m, 2H), 2.80 (m, 2H), 2.63 (m, 2H).

[0027] NMR 13 C (JMOD 500 MHz, CDCl3, δ ppm): 63.74 (t, J=21.35 Hz), 61.70, 61.30, 50.79 (d, J=5.89 Hz), 44.34 (d, J=6.78 Hz), 36.86 (t, J=4.66 Hz).

[0028] IR (KBr, cm -1): 3058, 2985, 2952 (CH2-epoxy), 1477, 1459, 1425, 1382 (C-Oep), 1344, 1253 (CO), 1191, 1151 (POC), 1066, 1000 (C-Oep), 962, 912, 854, 836, 800 (POC), 763, 734, 677, 601, 416, 405.

Claims

1. A method for producing 3,9-bis(oxiran-2-ylmethoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (5) consisting of reacting glycidol (1) and 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane (4) in a molar ratio of 2:1 in dichloromethane, carrying out the reaction at room temperature for 60-90 minutes, isolating the product by evaporating the solvent, filtering triethylamine hydrochloride from the solution of the reaction product in MTBE and maintaining the reaction product in a membrane pump vacuum at room temperature:

2. The method according to claim 1, in which the reaction product is maintained in a vacuum of a membrane pump at room temperature to remove glycidol.

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