Method for producing phosphate compound condensates

Abstract

To provide a manufacturing method that can efficiently produce long-chain phosphate compound condensates. [Solution] A method for producing a phosphoric acid compound condensate by reacting a phosphoric acid compound containing two OH groups and potassium at a temperature range of 300°C to 1800°C under specific low pressure and / or a bubbling environment of inert gases.

Description

Technical Field

[0001] The present invention relates to a method for producing a phosphoric acid compound condensate.

Background Art

[0002] Phosphoric acid compound condensates such as polyphosphoric acid and its sodium salts (hereinafter collectively referred to as polyphosphoric acid) are considered to have various physiological activity effects. For example, in Patent Document 1, it is disclosed that polyphosphoric acid having a chain length of about 60 has an effect of stabilizing FGF (fibroblast growth factor), and thus an effect of promoting wound healing and collagen production is expected. Further, in Patent Document 2, it is shown that the chain length of polyphosphoric acid in vivo is about 800, and it is expected that compounds having a chain length less than this will exhibit physiological activity, and it has been confirmed that polyphosphoric acid having a chain length of 100 or more has an antibacterial effect.

[0003] In Non-Patent Document 1, as a general method for producing polyphosphate, a relatively simple method of heating and melting sodium dihydrogen phosphate and quenching it is suitable, and it is disclosed that polyphosphates having various chain lengths can be obtained depending on the temperature and time during production. From the content of FIG. 11 thereof, it can be seen that obtaining a condensate with a long chain length requires a high temperature and a long time. Also, there is a disclosure suggesting that in the production of polyphosphate on an industrial scale, components acting as chain breakers such as sulfates are likely to be mixed into the reaction apparatus, and it is relatively difficult to obtain a polyphosphate with a long chain length.

[0004] Patent Document 3 discloses a continuous melting furnace capable of producing phosphate glass at several hundred kg / h. In the examples of Patent Document 3, polyphosphates having an average chain length of 35 to 38 are obtained under the condition of a reaction temperature of 580°C to 850°C.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] [Non-Patent Document 1] Shiro Ueda, "Production of Condensed Phosphates," Electrochemistry, The Electrochemical Society, 1963, Vol. 30, No. 11, pp. 798-807. [Overview of the project] [Problems that the invention aims to solve]

[0007] As mentioned above, long-chain polyphosphates have the potential to exhibit excellent physiological activity and are considered suitable as raw materials for drug discovery. However, obtaining long-chain polyphosphates with chain lengths exceeding 100 tends to require a relatively long time.

[0008] Furthermore, the long-chain polyphosphates obtained by the condensation method described above have a relatively broad molecular weight distribution, and therefore contain small amounts of polyphosphates with chain lengths exceeding 100. It is conceivable that these could be separated and extracted to obtain polyphosphates with chain lengths exceeding 100, but this would clearly increase manufacturing costs.

[0009] In the inventors' studies, it appears that even when using reaction apparatus that is less susceptible to contamination by components such as chain breakers, such as platinum crucibles, it is difficult to obtain long-chain polyphosphates in relatively large-scale reactions. In other words, it was suspected that there are other factors that make it difficult to obtain long-chain polyphosphates.

[0010] Therefore, the object of the present invention is to provide a method for efficiently obtaining long-chain phosphate compound condensates. Furthermore, by discovering this method, the object of the present invention is to suitably provide raw materials for producing compounds that exhibit higher physiological activity than conventional compounds, and compounds that exhibit diverse physiological activity. [Means for solving the problem]

[0011] As a result of investigations to solve the above-mentioned problems, the present inventors have found that by carrying out a condensation reaction of a phosphate compound containing liquid potassium under specific temperature conditions, a reduced pressure environment, and / or a bubbling environment of inert gases, it is possible to obtain an extremely long-chain phosphate compound condensate in a relatively short time, and have completed the present invention. That is, the present invention is specified by the following requirements.

[0012] [1] A phosphate compound that satisfies the following requirement (c) (a) Reaction temperature range of 300℃ to 1800℃, (b) A method for producing a phosphorus compound condensate by reacting under a pressure of 0.0001 Pa to 0.08 MPa and under conditions selected from a bubbling state of inert gases. (c) The phosphate compound includes a phosphate compound specified by the following general formula (1). [ka] (In formula (1) above, O is an oxygen atom, P is a phosphorus atom, H is a hydrogen atom, - is a covalent bond, X is a substituent containing an atom selected from oxygen, nitrogen, hydrogen, sulfur, and alkali metals, and n is an integer from 1 to 10. X contains potassium (K). If there are multiple X groups, one or more of them are potassium-containing groups.)

[0013] [2] A method for producing a phosphorus compound condensate according to [1], wherein the potassium-containing group is an oxypotassium group (OK group).

[0014] [3] The production method of the phosphoric acid compound condensate according to [2], wherein when X contains a substituent other than the OK group, the substituent other than the OK group is a substituent (OA0 group) selected from an OA group, an OH group, and an ONH4 group. (However, A is an alkali metal atom excluding potassium.)

[0015] [4] The production method of the phosphoric acid compound condensate according to [3], wherein A is sodium (Na).

[0016] [5] The production method of the phosphoric acid compound condensate according to [3] or [4], wherein the molar ratio (OA0 / OK) of the OA0 group to the OK group is 2.0 or less.

[0017] [6] The production method of the phosphoric acid compound condensate according to [3] or [4], wherein the molar ratio (OA0 / OK) of the OA0 group to the OK group is 1.3 or less.

[0018] [7] The production method of the phosphoric acid compound condensate according to any one of [3] to [6], wherein the OA0 group is an ONa group. [Advantages of the Invention]

[0019] By using the production method of the phosphoric acid compound condensate of the present invention, a polyphosphoric acid compound having a long chain length, for example, a chain length in terms of monophosphate skeleton units far exceeding 100, can be produced in a relatively simple method and in a relatively short time. [Brief Description of the Drawings]

[0020] [Figure 1] It is a chart obtained by GPC measurement of the phosphoric acid compound condensates obtained in the examples and comparative examples of the present invention. [Embodiments for Carrying Out the Invention]

[0021] The present invention relates to (a) A reaction temperature range of 300°C to 1800°C, (b) Under a pressure of 0.0001 Pa to 0.08 MPa and under an environment selected from inert gas bubbling conditions, (c) React with the phosphoric acid compound specified by the following formula (1) (described later), This is a method for producing phosphoric acid compound condensates.

[0022] (Reaction temperature (a)) The reaction temperature (a) in the method for producing the phosphorus compound condensate of the present invention is in the range of 300 to 1800°C. The lower limit of the reaction temperature (a) is preferably 400°C, more preferably 450°C, even more preferably 500°C, and particularly preferably 550°C. On the other hand, the upper limit is preferably 1500°C, more preferably 1200°C, even more preferably 1100°C, and particularly preferably 1000°C.

[0023] In the manufacturing method of the present invention, it is often preferable that the phosphoric acid compound be in liquid form, and within the aforementioned temperature range, the phosphoric acid compounds used in the present invention generally tend to be in liquid form. At temperatures below the aforementioned temperature range, the reaction is more likely to become solid, and the reaction may not proceed smoothly. On the other hand, at temperatures above the aforementioned temperature range, the stability of the resulting phosphate compound condensate may decrease (for example, some or all of it may decompose).

[0024] (Pressure / Bubbling of inert gases (b)) One preferred embodiment of the method for producing the phosphoric acid compound condensate of the present invention is to be carried out under a reduced pressure environment. The pressure range is 0.0001 Pa to 0.08 MPa. The lower limit of the pressure range is preferably 0.1 Pa, more preferably 1 Pa, even more preferably 10 Pa, and particularly preferably 100 Pa. On the other hand, the upper limit is preferably 0.05 MPa, more preferably 0.01 MPa, even more preferably 0.005 MPa (5 kPa), and particularly preferably 0.003 MPa (3 kPa).

[0025] At pressures exceeding the aforementioned pressure range, the condensation reaction may not proceed easily. On the other hand, at pressures lower than the aforementioned pressure range, there is almost no water generation due to the condensation reaction, meaning the reaction is considered to be almost complete.

[0026] Condensation reactions are generally in equilibrium with decomposition reactions such as hydrolysis. Therefore, methods to make the equilibrium state predominantly condensation reactions by removing by-product water under a reduced pressure environment are well known. However, in condensation reactions of phosphorylated compounds, which occur under conditions far exceeding the boiling point of water, such as the reaction temperature (a) mentioned above, and do not require the high resin pressure seen in solid-phase polymerization processes in polyester production, the effect of a reduced pressure environment is usually considered to be limited.

[0027] However, as will be described later, in the method using potassium-containing phosphate compounds as raw materials, we found an unexpected effect: by creating the aforementioned reduced-pressure environment, the degree of polymerization of the resulting phosphate compound condensate dramatically increased compared to when potassium-free phosphate compounds were used. The factors contributing to this effect will be described later.

[0028] In the present invention, one preferred embodiment of the method for producing a phosphate compound condensate is a method of supplying inert gases, that is, a method of reacting a phosphate compound described later in a liquid state under a bubbling state of inert gases. Reacting a phosphate compound in a liquid state under a bubbling state of inert gases means reacting the phosphate compound with a liquid phosphate compound while supplying inert gases in a bubbling manner. In this case, it is preferable to supply inert gases at a flow rate of 0.1 to 100 L / min per 1 kg of the phosphoric acid compound.

[0029] The lower limit of the flow rate is preferably 0.2 L / min, more preferably 0.3 L / min. On the other hand, the upper limit is preferably 50 L / min, more preferably 30 L / min, even more preferably 20 L / min, and particularly preferably 10 L / min. In this specification, the flow rate may be expressed as a value having the dimension of volume per unit time. Within the aforementioned numerical range, it is possible to effectively extend the chain length of the phosphate compound condensate while suppressing adverse effects such as splashing of the liquid phosphate compound during the reaction.

[0030] Examples of the aforementioned inert gases include air, oxygen, and other known inert gases such as nitrogen and argon, which are Group 18 elements of the periodic table (so-called noble gases). Of course, it is preferable to use a so-called dry gas, from which components that contribute to decomposition, such as moisture, have been removed to a level that does not contradict the purpose of the present invention.

[0031] Known methods for preparing such a dry gas include passing the gas through a column packed with molecular sieves and known water adsorbents such as alumina. The aforementioned inert gases are preferably air or nitrogen, considering factors such as availability, safety, and cost.

[0032] (Phosphate compound (c)) The aforementioned phosphate compound is a compound that satisfies the following requirement (c). [ka] (In formula (1) above, O is an oxygen atom, P is a phosphorus atom, H is a hydrogen atom, - is a covalent bond, X is a substituent containing an atom selected from oxygen, nitrogen, hydrogen, sulfur, and alkali metals, and n is an integer from 1 to 10. X is a potassium (K)-containing group. If there are multiple X groups, one or more of them are potassium-containing groups.) In this invention, element names and element symbols may have multiple meanings, such as "representing the atom itself" or "representing the manner in which a substituent is formed (for example, "-O-" or "-H")."

[0033] The potassium-containing group is preferably an OK group (oxypotassium group).

[0034] Since the aforementioned phosphoric acid compound contains at least two OH groups (hydroxyl groups), these hydroxyl groups undergo dehydration condensation, i.e., the growth reaction of polycondensation proceeds, gradually growing into a phosphoric acid compound with a longer chain length, yielding a phosphoric acid compound condensate. As mentioned above, this reaction is generally known to be an equilibrium reaction, and the growth reaction proceeds efficiently by removing water during the reaction.

[0035] If n is 2 or more, there will be multiple X groups. These multiple X groups may be the same or different from each other. If the phosphoric acid compound has a structure in which multiple X groups exist, it is sufficient that one or more of the multiple X groups contain a potassium atom. In this case, preferred substituents that do not contain a potassium atom (hereinafter also referred to as substituent X0) are those selected from OA groups, OH groups, and ONH4 groups. (However, A is an alkali metal atom other than potassium.) The alkali metal (A) is preferably sodium. The substituent selected from OA groups, OH groups, and ONH4 groups may be referred to as the OA0 group.

[0036] Examples of substituents X0 include substituents that form salts such as hydroxyl groups, mercapto groups (SH groups), amino groups, oxyammonium groups (ONH4 groups), oxylithium groups (OLi groups), oxysodium groups (ONa groups), thiolithium groups (SLi groups), and thiosodium groups (SNa groups). Among these, oxysodium groups (ONa groups) are particularly preferred.

[0037] Multiple types of X0 can be used. For example, if one or more of the X0 are hydroxyl groups, it is obvious that the condensate can have a (partially) cross-linked structure in addition to a linear structure.

[0038] Examples of such phosphorylated compounds include potassium dihydrogen phosphate, potassium pyrophosphate, potassium thiophosphorate, and other potassium phosphate analogs, as well as compounds in formula (1) where X has a potassium carboxylate skeleton, potassium sulfonate skeleton, potassium cyanate skeleton, etc. Among these, potassium dihydrogen phosphate is preferred considering its availability and physiological activity. Furthermore, polymers of the above-mentioned potassium-containing compounds with other phosphates are also examples of the phosphoric acid compounds of the present invention. Representative examples of the other phosphoric acids include phosphoric acid, sodium phosphate, lithium phosphate, and ammonium phosphate. Other examples include inorganic phosphoric acid compounds such as phosphorous acid, thiophosphoric acid, and aminophosphoric acid, pyrophosphate compounds such as pyrophosphate, magnesium pyrophosphate, calcium pyrophosphate, and zinc pyrophosphate, and phosphoric acid compounds in which X is a hydrocarbon group, such as methylphosphonic acid and ethylphosphonic acid. Of course, the potassium-containing phosphoric acid compound polymer is also a preferred embodiment. These potassium-containing phosphate compounds are preferably dimers to decamers, more preferably dimers to heptamers, and even more preferably dimers to pentamers. Also included are (co)polymers of these compounds, and (co)polymers of the phosphate compound and the potassium-free phosphate compound described later.

[0039] In formula (1) above, n is an integer between 1 and 10. For example, potassium dihydrogen phosphate is a compound that corresponds to the case where n=1. Usually, the present invention often uses compounds that correspond to n=1, but of course, embodiments that use phosphorus compounds, which are low condensates of such compounds, as raw materials are also included in the present invention. The upper limit of n is preferably 7, more preferably 5, even more preferably 4, and particularly preferably 3.

[0040] In the method for producing the phosphorus compound condensate of the present invention, it is also possible to use the phosphorus compound and a phosphorus compound that does not contain potassium atoms in combination. Preferred examples of such compounds include those with structural formulas represented by the following general formula (2).

[0041] [ka] (In formula (2) above, O is an oxygen atom, P is a phosphorus atom, H is a hydrogen atom, - is a covalent bond, X0 is a substituent containing an atom selected from oxygen, nitrogen, hydrogen, sulfur, and alkali metals, and n0 is an integer from 1 to 10. X0 is a group that does not contain potassium (K).)

[0042] Examples of X0 include substituents similar to those in the phosphoric acid compound specified by formula (1), and preferred examples include substituents selected from OA groups, OH groups, and ONH4 groups. (However, A is an alkali metal other than potassium.) The alkali metal (A) is preferably sodium.

[0043] Furthermore, since it is obvious that reactive substituents such as hydroxyl groups react with alkali metals, for example, it is of course possible to convert them to other substituents by contacting them with compounds such as alkali metals, alkali metal hydroxides (NaOH, KOH, etc.), carbonates (Na2CO3, NaHCO3, etc.), chlorides (NaCl, KCl, etc.), phosphoric acid, and alkali metal phosphates (NaH2PO4, Na2HPO4, Na3PO4, etc.) during or after the condensation reaction.

[0044] Thus, in the present invention, various methods other than the condensation reaction can be used in combination to produce phosphate compound condensates with diverse structures. Specific examples of potassium-free phosphate compounds include those similar to the potassium-free phosphate compounds described in the explanation of formula (1) above. Preferably, phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, ammonium dihydrogen phosphate, etc. Among these, sodium dihydrogen phosphate is the most preferred from the viewpoint of ease of availability and ease of production.

[0045] The aforementioned n0 is an integer from 1 to 10. For example, sodium dihydrogen phosphate is a compound that corresponds to the case where n0=1. In the present invention, compounds that correspond to such n0=1 are often used, but of course, embodiments that use phosphorus compounds, which are low condensates thereof, as raw materials are also included in the present invention. The upper limit of the aforementioned n0 is preferably 7, more preferably 5, even more preferably 4, and particularly preferably 3. If n0 is 2 or more, the multiple X0s may be the same or different from each other.

[0046] The molar ratio of the phosphoric acid compound of formula (1) to the potassium-free phosphoric acid compound represented by formula (2) is preferably 5 moles or less, more preferably 3 moles or less, even more preferably 2.0 moles or less, particularly preferably 1.5 moles or less, and especially preferably 1.3 moles or less, of the compound of formula (2) per mole of potassium of formula (1).

[0047] While the aforementioned preferred lower limit is of course zero, as will be described later, there are cases where the presence of a potassium-free phosphoric acid compound is preferable. In such cases, the more preferred lower limit for the potassium-free phosphoric acid compound relative to 1 mole of potassium in formula (1) is 0.01 moles, even more preferably 0.1 moles, particularly preferably 0.15 moles, and especially preferably 0.18 moles.

[0048] In other preferred embodiments, it is preferable that the amount of OA0 groups in the phosphoric acid compound used is 5.0 moles or less per mole of OK groups. More preferably, it is 3.0 moles or less, even more preferably 2.0 moles or less, particularly preferably 1.5 moles or less, and especially preferably 1.3 moles or less. The preferred lower limit mentioned above is, of course, zero, but as will be described later, there are cases where the presence of OA0 groups is preferable. In such cases, the more preferred lower limit for OA0 groups relative to 1 mole of OK groups is 0.01 moles, even more preferably 0.1 moles, particularly preferably 0.15 moles, and especially preferably 0.18 moles.

[0049] In the present invention, the holding time within the temperature range essentially corresponds to the condensation reaction time, and is preferably 10 minutes or more, more preferably 30 minutes or more, even more preferably 1 hour or more, and particularly preferably 1.5 hours or more. The upper limit of the time is preferably 24 hours, more preferably 16 hours, even more preferably 12 hours, and particularly preferably 8 hours.

[0050] The phosphoric acid compounds of formulas (1) and (2) above are compounds containing at least two OH groups (hydroxyl groups). Through dehydration condensation of these hydroxyl groups, i.e., through the growth reaction of polycondensation, they gradually grow into phosphoric acid compounds with longer chain lengths, yielding phosphoric acid compound condensates. This reaction is generally known to be an equilibrium reaction, and it is well known that removing water during the reaction allows the growth reaction to proceed more efficiently.

[0051] The manufacturing method of the present invention tends to easily produce phosphorylated compound condensates with a high degree of polymerization. The inventors speculate as follows on the reason for this increase in the degree of polymerization. This increase in the degree of polymerization will also be referred to as "chain length extension" below. The condensation reaction of phosphoric acid compounds typically occurs at high temperatures exceeding 300°C, and sometimes around 1000°C, as described above. Therefore, it would generally be assumed that the water generated in the condensation reaction evaporates naturally. On the other hand, the inventors' research has shown that the chain length of the phosphoric acid compound condensate tends to become difficult to extend beyond a certain point. This is also true for materials that are less susceptible to disturbances, such as platinum crucibles.

[0052] Since potassium is known to exhibit stronger basicity compared to sodium, the phosphate compound represented by formula (1) is thought to have a potential to undergo polycondensation easily. However, it is also possible that the resulting aggregate of phosphate compounds has a strong interaction with some water, making it difficult to remove the water produced as a by-product during the condensation reaction.

[0053] The present invention provides a method for producing phosphate compound condensates that has the potential to be highly productive, as it allows for the easy acquisition of phosphate compound condensates with high molecular weight even when rapidly cooled after the polycondensation reaction. The existence of potassium polyphosphate salts with high molecular weights has been reported to date. Methods for obtaining such potassium polyphosphate salts have been reported to require either a long heating reaction process or a slow cooling and crystallization process. In this method, due to the high basicity of potassium, the small amount of water remaining in the system is separated from the potassium polyphosphate salt during the crystallization process, creating an environment where hydrolysis of the potassium polyphosphate salt itself is unlikely. In other words, it is thought that a long crystallization process is necessary to obtain potassium polyphosphate salts with high molecular weights. Furthermore, since sodium polyphosphate salts can take on various crystalline forms, it is thought that it may be difficult to obtain the same effect of increasing molecular weight through crystallization as with potassium polyphosphate salts.

[0054] Based on this information, one possible reason why the method for producing phosphate compound condensates according to the present invention can efficiently produce phosphate compound condensates with a high degree of polymerization is that potassium is a relatively large element compared to sodium. This is because, due to the size of potassium, the resulting phosphate compound condensates have a rigid structure such as a helical structure, which restricts the degree of freedom of the higher-order structure when adsorbing water. Therefore, it is thought that water tends to be easier to remove by methods such as creating a relatively low-pressure environment or bubbling with inert gases (where water is removed along with the inert gases). In other words, in the case of sodium salts, the phosphate compound condensate structure is relatively flexible, making it easy to form a higher-order structure with strong interactions that easily holds water molecules, so it is possible that water molecules tend to be relatively difficult to remove. Furthermore, it is thought that the fact that sodium polyphosphate salts have diverse crystalline forms may also be due to the aforementioned flexible structure.

[0055] In the method for producing phosphate compound condensates of the present invention, it is sometimes easier to obtain phosphate compound condensates with higher molecular weights, such as condensates with molecular weights exceeding the exclusion limit in GPC measurement, when a potassium-containing phosphate compound and a phosphate compound containing other elements such as sodium coexist. This is thought to be because if the condensate of only potassium-containing phosphate compound has an overly rigid structure, the condensation reaction may not proceed easily. In such cases, it can be considered that the aforementioned drawbacks are mitigated and the condensation reaction is promoted when a phosphate compound containing other elements such as sodium is used in combination.

[0056] Furthermore, since the method of the present invention is one that easily removes water even if it remains in the reaction state at high temperatures, the crystallization step which requires a long time becomes unnecessary, and a potassium polyphosphate salt with a high molecular weight can be obtained even when a rapid cooling method is used.

[0057] Based on the above reasoning, it can be considered that a method of bubbling the inert gases, which have the effect of physically promoting the movement of polymer chains, is more preferable.

[0058] Therefore, it can be considered that the chain length can be adjusted by changing the atmospheric pressure in the reaction system due to reduced pressure, or by changing the supply flow rate of the inert gases. Of course, if this is combined with changing the reaction temperature, even more precise adjustment of the chain length will be possible.

[0059] The pressure adjustment method and the method for supplying inert gases to a liquid phosphoric acid compound of the present invention can employ known methods without limitation. Preferred methods include a method of removing gas (including water vapor) from the reaction system using a vacuum pump, and a method of inserting a gas supply nozzle into the liquid phosphoric acid compound and supplying the inert gases.

[0060] In the bubbling method using inert gases, it is obvious that the supply location of the inert gases is most efficient at the bottom of the reactor. However, the gas supply location can be changed depending on the purpose, such as adjusting the chain length and chain length distribution. The method of combining the aforementioned pressure adjustment method with the aforementioned bubbling method using inert gases is, of course, also within the scope of the present invention.

[0061] In the present invention, the chain length can, of course, be adjusted by applying any known molecular weight adjustment method in polycondensation reactions, including adjusting the pH in the reaction system, in addition to the methods described above.

[0062] The method for producing phosphate compound condensates of the present invention can be applied regardless of the reaction scale. Specifically, it can be applied from a few grams to a large scale of 10 cubic meters, as shown in the examples of the present invention. From an industrial standpoint, the amount of phosphate compound used as raw material is preferably 400 g or more. The lower limit is more preferably 800 g, even more preferably 1 kg, and particularly preferably 1.2 kg. In other words, the reaction vessel used in the production method of the present invention is preferably large enough to hold the above amount of phosphate compound. The preferred size of the reaction vessel is an internal volume of 0.5 liters or more, more preferably 1 liter or more, even more preferably 1.5 liters or more, particularly preferably 2 liters or more, and especially preferably 2.5 liters or more. There is no particular upper limit, but as mentioned above, it is preferable to have an apparatus scale within a realistic range, given that apparatus using expensive materials such as platinum is preferred. A specific preferred upper limit is 10 cubic meters, more preferably 5 cubic meters, even more preferably 1 cubic meter, particularly preferably 500 liters, and especially preferably 300 liters.

[0063] Thus, the present invention is expected to enable the efficient mass production of long-chain phosphate compound condensates on an industrial scale. The method for producing the phosphorus compound condensate of the present invention can utilize known processes such as batch, semi-batch, and continuous processes without limitation. From the viewpoint of controlling chain length, the batch process tends to be preferred. On the other hand, from the viewpoint of production efficiency, the continuous process is preferred.

[0064] The chain length of the phosphate compound condensate obtained by the production method of the present invention is 60 or more, more preferably 80 or more, even more preferably 100 or more, particularly preferably 120 or more, and especially preferably 150 or more, as a number-average chain length. The preferred upper limit is not particularly meaningful, but considering that it serves as a raw material for compounds exhibiting physiological activity, it is preferably 10,000 or less, more preferably 8,000 or less, and even more preferably 6,000 or less. Furthermore, the basic unit of the chain length mentioned above is defined as a structural unit containing one phosphorus atom.

[0065] Furthermore, the average chain length mentioned above can be calculated from the molecular weight information obtained by GPC. 31 In 1P NMR measurement, the number-average chain length can be determined from the area intensity ratio by utilizing the fact that the chemical shifts of phosphorus at the ends of a polyphosphate chain and phosphorus within the chain are clearly different.

[0066] The long-chain phosphate compound condensates easily obtained by the manufacturing method of the present invention are expected to have physiological activity, and are therefore suitable for use as raw materials for various pharmaceuticals and other products. In particular, since the present invention is expected to easily produce condensates with longer chain lengths than conventional methods, it is anticipated to contribute to the discovery of pharmaceuticals with unprecedented physiological activity. Furthermore, it can be used without limitation in applications that utilize known phosphate compound condensates.

[0067] Furthermore, the phosphate compound condensates obtained as described above can, of course, be used as raw materials to obtain phosphate compound condensates of suitable chain lengths for specific applications by removing the low-chain group by known methods such as solvent fractionation, or by separating the high-chain group by GPC. It should be obvious that by using such methods, it is possible to obtain phosphate compound condensates of suitable long chain lengths with a higher yield than conventional methods. [Examples]

[0068] Examples 1-4 and Comparative Examples 1-3 differ in the potassium / sodium (K / Na) molar ratio of the molten raw materials or the reaction pressure. The chain length (molecular weight) distribution of the phosphate compound condensates produced in Examples 1-4 and Comparative Examples 1-3 was measured using the gel permeation chromatography (GPC) method described below, and the change in the chain length distribution of each phosphate compound condensate was evaluated.

[0069] (GPC analysis conditions) (Sample pretreatment) The sample was weighed into a 30 mL vial, 10 mL of GPC mobile phase was added per 10 mg of sample, the vial was sealed tightly, and the sample was allowed to stand at room temperature overnight to dissolve. This solution was filtered through a 0.45 μm hydrophilic PTFE membrane filter cartridge (Millex-LCR 33 mm; Merck), and the filtrate was used for measurement. (Measurement conditions) Column / Temperature: Two OHpak SB-806M HQ columns (particle size 13μm, inner diameter 8.0mm, length 300mm, Shodex) connected in series / 40℃ Mobile phase: 0.1M NaCl aqueous solution Flow rate: 1.0mL / min Injection volume: 100μL Detection method: RI (Refractive Index) Column Calibration: EasiVial PEG / PEO Polyethylene Glycol Oxide (Agilent Technologies) Molecular weight calibration: Relative calibration method (PEG / PEO conversion) Equipment: KP-22-13 dual pump (From), 717plus automatic injector (Waters Japan), RI-101 differential refractive index detector (Shodex)

[0070] (Example 1) 2.40 g of sodium dihydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 7.60 g of potassium dihydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in a 50 mL platinum crucible and mixed thoroughly. The molar ratio (Na / K) of sodium in the sodium dihydrogen phosphate and potassium in the potassium dihydrogen phosphate used was 0.36. The crucible was placed in an electric furnace "KDF-900GL" (manufactured by Denken Corporation), and the mixture was melted at 800°C for 4 hours while reducing the pressure inside the electric furnace to 1.2 kPa using the vacuum pump "GVD-200A" (manufactured by ULVAC KIKO, Inc.) attached to the electric furnace (hereinafter referred to as "reduced pressure operation").

[0071] Subsequently, the vacuum pump was stopped, nitrogen gas was added to return the furnace to atmospheric pressure, and the crucible was removed. The molten salt was then poured onto a 30 cm square, 1 cm thick copper plate and rapidly cooled to obtain a glassy phosphate compound condensate.

[0072] (Example 2) A phosphate compound condensate was obtained in the same manner as in Example 1, except that 2.61 g of sodium dihydrogen phosphate and 7.39 g of potassium dihydrogen phosphate were used (the molar ratio Na / K = 0.4).

[0073] (Example 3) A phosphate compound condensate was obtained in the same manner as in Example 1, except that 4.69 g of sodium dihydrogen phosphate and 5.31 g of potassium dihydrogen phosphate were used (with the aforementioned molar ratio Na / K = 1).

[0074] (Example 4) A phosphate compound condensate was obtained in the same manner as in Example 1, except that 10 g of potassium dihydrogen phosphate was used and sodium dihydrogen phosphate was not used. The molar ratio (Na / K) was 0.

[0075] (Comparative Example 1) A phosphate compound condensate was obtained in the same manner as in Example 1, except that 10.0 g of sodium dihydrogen phosphate was used instead of potassium dihydrogen phosphate.

[0076] (Comparative Example 2) A phosphate compound condensate was obtained in the same manner as in Example 1, except that 2.27 g of sodium dihydrogen phosphate and 7.73 g of potassium dihydrogen phosphate were used (the molar ratio Na / K = 0.33), and no vacuum operation was performed.

[0077] (Comparative Example 3) A phosphate compound condensate was obtained in the same manner as in Example 1, except that potassium dihydrogen phosphate was not used, 10.0 g of sodium dihydrogen phosphate was used, and the vacuum operation was not performed.

[0078] The manufacturing conditions and measurement results are summarized in Table 1. Figure 1 shows charts of GPC measurements for the phosphate compound condensates produced in Examples 1-4 and Comparative Examples 1-3. Furthermore, Table 1 summarizes the Mw and Mn values ​​calculated based on the charts (Mw: weight-average molecular weight, Mn: number-average molecular weight).

[0079] [Table 1]

[0080] From the results described above, it can be seen that the method of the present invention makes it possible to efficiently produce polymer phosphate compound condensates with Mw of 100,000 or more and Mn of 10,000 or more in a short time of 4 hours.

[0081] From the GPC measurement chart (Figure 1) of the phosphate compound condensates obtained in Examples 1 to 3, it is possible that the molecular weight of the obtained phosphate compound condensates contains components that exceed the exclusion limit of the GPC column. Therefore, the actual molecular weight may be higher than the value mentioned above.

[0082] On the other hand, the phosphate compound condensates obtained in Examples 1 to 4 are phosphate compound condensates that exhibit ultra-high molecular weight results, but they are fluid even at high temperatures, so they can be removed from the reaction apparatus in liquid form, and there are no difficulties in handling them. For this reason, it is possible that ultra-high molecular weight compounds that show results exceeding the exclusion limit exhibit a pseudo-ultra-high molecular weight result during GPC measurement due to large interactions between polymerization chains. In addition, the phosphate compound condensates obtained in Examples 1 to 3 contain polymers with relatively low molecular weights, so it is possible that these components contribute to their fluidity.

[0083] When comparing Examples 1-4 and Comparative Examples 1-3, the increase in Mw and Mn values ​​is limited when only sodium salt is melted at low pressure, or when potassium salt is added and melting is performed at atmospheric pressure. On the other hand, when potassium salt is added and melting is performed at low pressure, the Mw and Mn values ​​are significantly improved, suggesting that high molecular weight components are efficiently produced.

Claims

1. A phosphate compound that satisfies the following requirement (c) (a) Reaction temperature range of 300°C to 1800°C, (b) A method for producing a phosphoric acid compound condensate by reacting under a pressure of 0.0001 Pa to 0.08 MPa and under conditions selected from a bubbling state of inert gases. (c) The phosphate compound includes a phosphate compound specified by the following general formula (1). 【Chemistry 1】 (In formula (1) above, O is an oxygen atom, P is a phosphorus atom, H is a hydrogen atom, - is a covalent bond, X is a substituent containing an atom selected from oxygen, nitrogen, hydrogen, sulfur, and alkali metals, and n is an integer from 1 to 10. X contains potassium (K). If there are multiple X groups, one or more of them are potassium-containing groups.)

2. A method for producing a phosphorus compound condensate according to claim 1, wherein the potassium-containing group is an oxypotassium group (OK group).

3. If X contains substituents other than OK groups, the substituents other than OK groups are OA groups, OH groups, and ONH groups. 4 Substituents selected from the group (OA 0 A method for producing the phosphorus compound condensate according to claim 2, wherein the base is... (However, A is an alkali metal atom other than potassium.)

4. A method for producing a phosphorus compound condensate according to claim 3, wherein A is sodium (Na).

5. The aforementioned OA 0 Molar ratio of the group to the OK group (OA 0 A method for producing a phosphorus compound condensate according to claim 3, wherein the ratio of (OK) is 2.0 or less.

6. The aforementioned OA 0 Molar ratio of the group to the OK group (OA 0 A method for producing a phosphorus compound condensate according to claim 3, wherein the ratio of (OK) is 1.3 or less.

7. The aforementioned OA ０ A method for producing a phosphorus compound condensate according to claim 3, wherein the group is an ONa group.

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