Method for the preparation of 3,3'-oxybis(1,1,1,3,5,5,5-heptamethyltrisiloxane)

Abstract

A method for preparing 3,3'-oxybis(1,1,1,3,5,5,5-heptamethyltrisiloxane) is provided. The 3,3'-oxybis(1,1,1,3,5,5,5-heptamethyltrisiloxane) is useful in foam formulations, such as polyisocyanurate and polyurethane foams.

Description

METHOD FOR THE PREPARATION OF 3 ,3'-OXYBlS( 1,1.1.3,5,5,5- HEPTAMETHYLTRISILOXANE)CROSS REFERENCE TO RELATED APPLICATIONS

[0001]

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 745,542 filed on January 15, 2025 under 35 U.S.C. §119 (e). U.S. Provisional Patent Application Serial No. 63 / 745,542 is hereby incorporated by reference.FIELD

[0002] This invention relates to a new method for preparation of 3,3'-oxybis( 1 , 1 , 1 , 3, 5,5,5-heptamethyltri siloxane). The 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) has high yield and high purity.INTRODUCTION

[0003] Decamethylcyclopentasiloxane (D5) has been used as a nucleator for polyurethane foams. However, there is an industry need to replace D5 and other cyclic siloxanes (e.g., D4, D6, and others) due to European Union REACH (Registration, Evaluation, Authorisation, and Restriction of Chemicals) and other regulations. Short chain linear polydimethylsiloxanes have the potential to replace D5, however, short chain linear polydimethylsiloxanes have the potential to generate cyclic siloxanes during storage and / or during or after use. However, dendritic siloxane oligomers have the potential to replace D5 without this potential to generate cyclic siloxanes. PCT Patent Publication W02020118646 discloses a composition for preparing polyisocyanurate and polyurethane foams. The composition includes a branched siloxane comprising at least three trimethylsiloxy groups.SUMMARY

[0004] This invention provides a method for preparing a product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). The method comprises: combining, under conditions to effect dehydration reaction, starting materials comprising 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxan-3-ol; 1,1,1,3,5,5,5-heptamethyltrisiloxane; and tris(pentafluorophenyl)borane; thereby preparing the product comprising 3,3'-oxybi s ( 1 , 1 , 1 , 3 , 5 , 5 , 5 -heptamethy Itri siloxane) .DETAILED DESCRIPTION

[0005] The method introduced above may comprise:optionally 1) preparing l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol by a method comprising: 1) combining, under conditions to effect hydrolysis reaction, starting materials comprising 1,1,1,3,5,5,5-heptamethyltrisiloxane, water, a palladium catalyst, optionally a solvent, andoptionally a buffer, thereby forming an intermediate comprising the 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxan-3-ol and a side product comprising water;optionally 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol;3) combining, under conditions to effect dehydration reaction, starting materials comprising l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol; 1,1,1,3,5,5,5-heptamethyltrisiloxane; and tris(pentafluorophenyl)borane, thereby preparing the product comprising 3,3'-oxybis( 1,1,1 ,3 ,5,5,5-heptamethyltrisiloxane) ; andoptionally 4) purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

[0006] In the method described herein, l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol has formulaThe 1,1, 1,3, 5,5,5-heptamethyltrisiloxan-3-ol is commercially available, for example, from Bench Chem of Pasadena, California, USA. Steps 1) and 2) described above are optional, and may be eliminated when, e.g., the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol is obtained from a commercially available source. The amounts of l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol and 1, 1,1, 3, 5,5,5-heptamethyltrisiloxane are not specifically restricted, however, they may be used in a molar ratio of 1 : 1 , alternatively 1.1 : 1 to 1 : 1.1 such that the amount of unreacted starting material may be minimized.

[0007] Alternatively, in the method described herein, the 1,1,1,3,5,5,5-heptamethyltrisiloxan-3-ol may be prepared by the method comprising: 1) combining, under conditions to effect hydrolysis reaction, starting materials comprising 1,1,1,3,5,5,5-heptamethyltrisiloxane, water, a palladium catalyst, optionally a solvent, and optionally a buffer, thereby forming an intermediate comprising the 1 ,1 ,1 ,3,5,5,5-heptamethyltrisiloxan-3-ol and a side product comprising water; and optionally 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol.

[0008] The 1,1,1,3,5.5,5-heptamethyltrisiloxane has formula:commercially available from various sources such as Sigma- Aldrich, Inc. of St. Louis, Missouri, USA; TCI America division of Tokyo Chemical Industry, of Portland, Oregon, USA; Oakwood Chemical of West Columbia, South Carolina, USA; and Fisher Scientific of Waltham, Massachusetts, USA.

[0009] The water is not specifically restricted. The water is not generally limited, and may be utilized neat (i.e., absent any carrier vehicles and / or solvents), and / or pure (i.e., free from, orsubstantially free from, minerals and / or other impurities). For example, the water may be processed or unprocessed prior to the reaction with 1,1,1,3,5,5,5-heptamethyltrisiloxane.Examples of processes that may be used for purifying the water include distilling, filtering, deionizing, reverse osmosis and combinations of two or more thereof. Alternatively, the water may be unprocessed (e.g. may be tap water, i.e., provided by a municipal water system or well water, used without further purification). Alternatively, the water may be purified before reaction with 1,1,1,3,5,5,5-heptamethyltrisiloxane. Alternatively, the water may be utilized as a mixture (e.g. solution or suspension) comprising a earner vehicle and / or solvent. The water may be utilized in any amount, which will be selected by one of skill in the art, depending on various factors, e.g., the particular palladium catalyst selected, the reaction parameters employed, the scale of the reaction (e.g. total amount of 1,1,1,3,5,5,5-heptamethyltrisiloxane to be converted).

[0010] The palladium catalyst may be a heterogeneous catalyst comprising palladium on a support, such as carbon. Suitable palladium catalysts are known in the art and are commercially available, e.g., from Sigma-Aldrich, Inc. of St. Louis, Missouri, USA. The amount of palladium catalyst depends on various factors including the conditions selected for the reaction, however the amount may be sufficient to provide at least 10 ppm of palladium metal based combined weights of the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol and 1,1,1,3,5,5,5-heptamethyltrisiloxane, alternatively at least 50 ppm; while at the same time the amount may be up to 500 ppm, alternatively up to 150 ppm, on the same basis. Alternatively, the amount of catalyst may be 10 ppm to 500 ppm, alternatively 50 ppm to 150 ppm, on the same basis.

[0011] The solvent is optional. The solvent is not specifically restricted and is exemplified by a ketone such as acetone, or tetrahydrofuran. The solvent may facilitate mixing of the 1.1.1.3.5.5.5-heptamethyltrisiloxane and the water.

[0012] The buffer may optionally be used in step 1) of the method described herein to neutralize the starting materials. The buffer may be a neutral phosphate buffer. For example, 1% to 10% phosphates in water as a buffer solution may be used.Step 1) of the method described herein may comprise combining, e.g., by mixing, the buffer, the solvent, and the palladium catalyst to form a first mixture; and adding the 1, 1,1, 3, 5,5,5-heptamethyltrisiloxane to the first mixture continuously or in aliquots. For example, the 1.1.1.3.5.5.5-heptamethyltrisiloxane may be added to the first mixture over a time period of 80 minutes to 120 minutes. These starting materials may be combined in a reactor with cooling and / or heating means, such as a jacket. Step 1) may be performed at a temperature of 10 °C to 30 °C. Optionally, step 1) may further comprise mixing the reactor contents after completion of the addition of 1,1,1,3,5,5,5-heptamethyltrisiloxane for a period of time to allow for completion of reaction, e.g., 5 minutes to 8 hours, alternatively 2 to 6 hours, and alternatively 4 hours.

[0013] When step 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol is present, step 2) may comprise removing the catalyst, removing the solvent, removing the side product, or a combination thereof. Removing the catalyst may be performed by any convenient means such as filtration, e.g., when a heterogeneous catalyst is used. Removing the solvent and / or the side product may be performed by any convenient means such as stripping, distillation, and / or evaporation (e.g., with a rotary evaporator), optionally with reduced pressure.

[0014] In the method described above starting materials comprising the 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxan-3-ol; 1,1,1,3,5,5,5-heptamethyltrisiloxane; and tris(pentafluorophenyl)borane may be combined under conditions to effect dehydration reaction, thereby preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). An additional solvent may optionally be used in this step, e.g., to facilitate mixing of the tris(pentafluorophenyl)borane and the other starting materials. The additional solvent may be an aromatic hydrocarbon, such as benzene, toluene, xylene, or a combination thereof; alternatively toluene. For example, step 3) may be performed by a technique comprising: optionally, i) dissolving the tris(pentafluorophenyl)borane catalyst in a solvent to form a catalyst solution, ii) mixing starting materials comprising 1,1,1,3,5,5,5-heptamethyltrisiloxane and the tris(pentafluorophenyl)borane catalyst, thereby preparing a second mixture, and iii) adding l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol to the second mixture.

[0015] The tris(pentafluorophenyl)borane used in the method has formulaTris(pentafluorophenyl)borane is commercially available from various sources, such as Sigma-Aldrich, Inc., TCI America, and Fisher Scientific. Tris(pentafluorophenyl)borane may be prepared by known methods, such as those disclosed in US Patent US5744646.

[0016] These starting materials used in the dehydration reaction step may be combined bymixing in a reactor with heating means, such as a jacket. An inert gas, such as nitrogen or argon, may be used to reduce oxygen content in the reactor. Alternatively, the 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxane; tris(pentafluorophenyl)borane; and the additional solvent may be combined in the reactor to form a second mixture. The l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol may be added to the second mixture continuously or in aliquots. For example, the 1 , 1 , 1 , 3, 5,5,5-heptamethyltrisiloxan-3-ol may be added over 60 minutes to 100 minutes, alternatively 80 minutes The l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol may be added to the second mixture with heating, e.g., at a temperature of 60 °C to 65 °C. Optionally, additional catalyst, or additional catalyst solution, may be added during step iii) from one to three times.

[0017] The method described herein may optionally further comprise one or more additional steps. The additional step may comprise neutralizing the catalyst by adding a neutralizing agent for the tris(pentafluorophenyl)borane catalyst after preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). The additional step may comprise purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). Purifying may comprise filtration to remove the neutralizing agent, when used. Any suitable neutralizing agent may be used. Suitable neutralizing agents for tris(pentafluorophenyl)borane catalyst, such as metal oxides or hydroxides (e.g., neutral alumina). Alternatively, purifying may comprise removing an unreacted starting material, a side product, and / or solvent, when used, such as by stripping, distillation, or evaporation. The resulting product comprises 3,3'-oxybis( 1 , 1 , 1, 3, 5,5,5-heptamethyltrisiloxane) with good yield and purity.EXAMPLES

[0018] The following examples are provided to illustrate the invention to one skilled in the art and are not to be construed so as to limit the scope of the invention set forth in the claims. The starting materials used in this invention are summarized below in Table 1.Table 1 - Starting Materials

[0019] In this Example 1, 87.7 g neutral phosphate buffer, 616.5 g of acetone, and 5.8 g of Pd / C catalyst (1% Pd) were mixed in a 2000 ml flask equipped with a mechanical stirrer, a thermal couple, and an adapter to a N2 bubbler. Under vigorous stirring, 541g of MD’M was added into the flask slowly in 100 minutes via a peristaltic pump. Temperature was maintained at ~20 °C in the flask. Stirring continued stirred at ~20 °C for 4 hours. Pd / C catalyst was filtered out through a 0.22 pm pore size membrane. Acetone and water were removed via rotary evaporation at ~20 °C and 9 torr for 2 hours. The resulting material was filtered through a 0.22 pm pore size membrane again. 551g of clear liquid MDOHM (1, 1,1, 3, 5,5,5-heptamethyltrisiloxan-3-ol) was collected. Yield was 95 area% by GC.

[0020] Next, 331.5 g of MD’M was charged into a 4-neck 1000 ml flask equipped with a mechanical stirrer, a thermal couple, and an adapter to a N2 bubbler. 1.49 g of 4.7% BCF / toluene solution was added to the flask. Under vigorous stirring, 346.1 g of the 1, 1,1, 3, 5,5,5-heptamethyltrisiloxan-3-ol prepared as described above, was added into the flask slowly in 80 minutes via a peristaltic pump. The temperature in the flask was maintained at 60-65 °C.Additional BCF catalyst (0.75g of 4.7% BCF / toluene solution was added in 3 times) was added to the flask to keep the reaction ongoing. Stirring was continued at ~20 °C for 1 hour. 32 g of neutral alumina was added to the flask to remove BCF catalyst. The alumina was filtered out after stirring at ~20 °C for 3 hours. Volatiles were removed via rotary evaporator at 40 °C and 10 torr for 1 hour. 649.2g of clear liquid (3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane)) was collected. GC-FID analysis indicated yield was 95.8 area %, and purity was 95.5 area %, based on the peak area of the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane.

[0021] In this Comparative Example 1, the procedure of Liao, Brook, et al. “Living synthesis of silicone polymers controlled by humidity”, European Polymer Journal, Volumel07, Pages 287-293 was performed. Yield was only 50 %, and purity by GC-FID was 95 area %.Comparative Example 4 showed that the reaction was difficult to control, and without wishing to be bound by theory it is thought that water deactivated the catalyst. The yield reported by Brook et al. was not achievable by practicing the process as described in the reference.The examples and results are summarized below in Table 2.Table 2Test Methods

[0022] Gas Chromatography (GC) Analysis was performed as follows: The GC analysis wasInitial Temp 300°C

[0023] Gas Chromatography Mass Spectrometry (GC-MS) Analysis was performed as follows: The GC-MS analysis was performed using an Agilent 7890 column program: 40°C (1 min) - 315°C (10 min) @ 10°C / min. The column, inlet, and detector information can be found below.&Industrial Applicability

[0024] The examples above demonstrate that unexpectedly high yield and high purity of the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) can be achieved using the method of this invention.

[0025] The 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) prepared as described herein may be used for preparing polyisocyanurate and polyurethane foams, e.g., as a nucleator, as described, for example, in PCT Patent Application Publication WO2020118646.Definitions and Usage of Terms

[0026] Any feature or aspect of the invention may be used in combination with any other feature or aspect recited herein. All amounts, ratios, and percentages herein are by weight, unless otherwise indicated by the context of the specification. The articles ‘a’, ‘an’, and ‘the’ each refer to one or more, unless otherwise indicated by the context of specification. The singular includes the plural unless otherwise indicated by the context of the specification. The SUMMARY and ABSTRACT are hereby incorporated by reference. The amounts of all starting materials in a composition total 100%. Any feature or aspect of the invention may be used in combination with any other feature or aspect recited herein. The abbreviations used herein have the definitions in Table A.Table A - Abbreviations

[0027] In this application, 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) refers to the> <>>compound of formula:

[0028] It is to be understood that the appended claims are not limited to express and particular compounds, compositions, or methods described in the detailed description, which may vary among embodiments, which fall within the scope of the appended claims. With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, different, special, and / or unexpected results may be obtained from each member of the respective Markush group independent from all other Markush members. Each member of a Markush group may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims.Embodiments of the Invention

[0029] In a first embodiment, a method for preparing a product comprising 3,3’-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane), wherein the method comprises:1) combining, under conditions to effect hydrolysis reaction, starting materials comprisingA) 1,1, 1 ,3,5,5,5-heptamethyltrisiloxane,B) water, andC) a palladium catalyst,optionally D) a solvent, andoptionally E) a buffer,thereby forming an intermediate comprising F) 1 ,1 , 1,3, 5,5,5- heptamethyltri siloxan-3 -ol ;2) purifying F) the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol;3) combining, under conditions to effect dehydration reaction, starting materials comprisingF) the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol,additional A) 1,1,1,3,5,5,5-heptamethyltrisiloxane, andG) tris(pentafluorophenyl)borane catalyst,thereby preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5- heptamethyltri siloxane); andoptionally 4) purifying the 3,3'-oxybis(l ,1 ,1 ,3,5,5,5-heptamethyltrisiloxane).

[0030] In a second embodiment, in the method of the first embodiment, step 3) is performed by a technique comprising:optionally i) mixing G) the tris(pentafluorophenyl)borane catalyst and a solvent, thereby forming a solution,ii) mixing starting materials comprisingthe additional A) 1,1,1,3,5,5,5-heptamethyltrisiloxane andG) the tris(pentafluorophenyl)borane catalyst, or the solution, when present, thereby preparing a mixture, andiii) adding F) the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol to the mixture.

Claims

CLAIMS:

1. A method for preparing a product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane), wherein the method comprises:optionally 1) combining, under conditions to effect hydrolysis reaction, starting materials comprising1 , 1 , 1 ,3 , 5 , 5 ,5 -heptamethyltri si lox ane,water, anda palladium catalyst,optionally a solvent, andoptionally a buffer,thereby forming an intermediate comprising the 1, 1,1, 3, 5,5,5- heptamethyltrisiloxan-3-ol and a side product comprising water;optionally 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol;3) combining, under conditions to effect dehydration reaction, starting materials comprising1.1.1.3.5.5.5-heptamethyltrisiloxan-3-ol,1.1.1.3.5.5.5-heptamethyltrisiloxane, and tris(pentafluorophenyl)borane catalyst,thereby preparing the product comprising 3,3'-oxybis(l, 1 , 1, 3, 5,5,5- heptamethyltrisiloxane); andoptionally 4) purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

2. The method of claim 1, wherein step 1) is present.

3. The method of claim 2, wherein step 1) comprises combining the buffer, the solvent, the palladium catalyst to form a first mixture and adding the 1,1,1,3,5,5,5-heptamethyltrisiloxane to the first mixture continuously or in aliquots.

4. The method of claim 2 or claim 3, wherein step 1) is performed at a temperature of 10 °C to 30 °C.

5. The method of any one of claims 2 to 4, wherein step 2) is present, and step 2) comprises removing the catalyst.

6. The method of claim 5, wherein step 2) further comprises removing the solvent andthe side product.

7. The method of any one of claims 1 to 5, wherein step 3) is performed by a technique comprising:optionally, i) dissolving the tris(pentafluorophenyl)borane catalyst in a solvent to form a catalyst solution,ii) mixing starting materials comprising 1,1,1,3,5,5,5-heptamethyltrisiloxane and the tris(pentafluorophenyl)borane catalyst, thereby preparing a second mixture, and iii) adding l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol to the second mixture.

8. The method of claim 6 or claim 7, wherein step iii) is performed over 60 to 100 minutes, continuously or in aliquots.

9. The method of any one of claims 6 to 8, wherein step iii) is performed at a temperature of 60 °C to 65 °C.

10. The method of any one of claims 6 to 9, wherein additional catalyst, or additional catalyst solution, is added during step iii) from one to three times.

11. The method of any one of claims 1 to 10, further comprising an additional step: neutralizing the catalyst by adding a neutralizing agent for the tris(pentafluorophenyl)borane catalyst after preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

12. A product comprising > 95 % 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) prepared by the method of any one of claims 1 to 11.

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