JPH0516364B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to carbon nitride having a novel chemical composition and a method for producing the same. Specifically, the present invention relates to carbon nitride having a novel chemical composition and a method for producing the same. This invention relates to carbon nitride useful as a polymer and a method for producing the same. [Prior Art and Problems to be Solved] Conventionally, various nitrogen compounds such as silicon nitride and boron nitride have been known. For example, silicon nitride is made by reacting silicon tetrachloride with ammonia to form silicon imide. It can be obtained by producing and then thermally decomposing it. However, carbon cannot be nitrided with nitrogen or ammonia, and so far no inorganic polymeric compound consisting only of carbon, nitrogen, and hydrogen has been known. [Means for Solving the Problems] Under the current circumstances, the present inventors have repeatedly studied the synthesis of carbon and nitrogen compounds under various conditions, and have found that carbon and nitrogen compounds such as cyanuric chloride and melamine have been synthesized. The present invention was achieved by discovering that a novel compound of carbon, nitrogen, and hydrogen can be synthesized by using a compound containing a triazine ring as a reaction raw material. That is, the present invention provides the general formula C ₃ NxHy (however,
Carbon nitride having a layered structure represented by 4≦X≦5, 0≦Y≦4), a method for producing the compound characterized by reacting cyanuric chloride with ammonia or melamine, and a firefly made of the compound. It is a light material. As mentioned above, the compound of the present invention can be obtained by reacting cyanuric chloride with ammonia or cyanuric chloride with melamine, and the conditions thereof will be described below. First, let's talk about the reaction conditions between cyanuric chloride and ammonia.Cyanuric chloride has a melting point of 154℃,
The boiling point is 190°C, and ammonia is a gas above 0°C, so the reaction will differ depending on the state of cyanuric chloride, but it will not react by any of the gas-solid reaction, gas-liquid reaction, or gas-gas reaction. The reaction proceeds. However, when the reaction is a gas-solid reaction or a gas-liquid reaction, the reaction is usually carried out at 400°C or lower, but the reaction does not proceed to the final product at once, and after taking an intermediate structure, this compound By thermally decomposing it again, it becomes the final product. In this way, once the reaction passes through an intermediate compound, it is necessary to carry out the reaction at a temperature below 400°C, but considering the stability of the intermediate, it is more preferable to carry out the reaction at a temperature of 0 to 200°C. is preferably carried out at 400 to 600°C. The final compound produced by this reaction was subjected to thermogravimetric analysis (hereinafter referred to as
Abbreviated as TG. ), it was found that sublimation and decomposition begin at 390℃, but this sublimation and decomposition rate is slow, so even if the intermediate is thermally decomposed at 400-600℃, the final product will easily decompose. Never. However, naturally, after the thermal decomposition of the intermediate is completed, it is necessary to lower the temperature to a temperature range in which decomposition does not proceed immediately. When a reaction proceeds by a gas-gas reaction, usually
The reaction is carried out at a temperature of 400 to 600°C, and a film-like product can be obtained depending on the reaction temperature, feed rate of raw materials, etc. When carrying out the above reaction, the amount of ammonia to cyanuric chloride is preferably 2 mol or more per 1 mol of cyanuric chloride, and 4 mol or more considering the reaction rate.
The ammonia used in the reaction can be used at any concentration, but from the viewpoint of ease of reaction control,
It is preferably 30 to 80%, and may be used after diluting with an inert gas such as nitrogen or argon. Next, the reaction between cyanuric chloride and melamine will be described. Melamine is known to sublimate and decompose at temperatures above 350°C, and since it remains solid up to this temperature, it is necessary to choose a temperature above 154°C, where cyanuric chloride exists as a liquid, in order to substantially proceed with the reaction. be. Therefore, a suitable reaction temperature is 154°C or higher and 350°C or lower. The reaction in this temperature range proceeds in the same way as in the case of cyanuric chloride and ammonia,
After passing through intermediates, it becomes the final product through thermal decomposition.
The temperature conditions etc. in this case are also the same. When carrying out the above reaction, the amount of melamine relative to cyanuric chloride must be such that the ratio of melamine to 1 mol of cyanuric chloride is 2 mol or more. The compound obtained by the above reaction has a triazine ring as one of its basic skeletons, and has the following structure in which nitrogen is bonded to each of the three carbons in this triazine ring. It is something that you have as a skeleton. However, during the reaction, it is difficult to break all the N-H bonds in ammonia or melamine in the temperature range of this reaction, and if the temperature is raised too much,
Because sublimation is delayed or the triazine ring itself decomposes, the N--H bond is not completely broken and some hydrogen remains. In this case, the nitrogen that is bonded to the three carbons in the diagram above is partially bonded to hydrogen, which is thought to have increased the ratio of nitrogen and hydrogen to carbon. Some hydrogen bonded to carbon can also be seen. The above structure can be determined by the elemental analysis described below,
This estimate was made by combining the results of X-ray diffraction, IR spectrum, and ESCA spectrum, and we will discuss them one by one. Table 1 shows the elemental analysis values of compounds produced under various conditions, and in the case of C ₃ NxHy, X takes a value of more than 4, and hydrogen also takes a value of 1 or more. In the future, it is possible to further reduce the hydrogen content by examining the reactive species, reaction method, reaction conditions, etc., but it is thought that it will be difficult to reduce the hydrogen content to 0%. . Next, the analysis results by X-ray diffraction method will be described. The X-ray diffraction diagram is shown in Figure 1, and the measurement conditions are Cu-Kα ray, 30KV, 20mA, scanning linearity: 1°/min, time constant: 1sec, full scale:
10Kcps, and the measurement conditions in the enlarged diagram are:
Cu-Kα line, 40KV, 30mA, scanning linearity: 1°/
min, time constant: 1sec, full scale: 10Kcps. First, there is a maximum diffraction line with a peak at 2θ of 26.5 to 28.0°. This is d = 3.3 Å, which corresponds to the Huander Waals distance, which is close to the interlayer distance of graphite (3.35 Å) and h-BN (3.33 Å), and 2θ is around 44.5° and 56°. The weak diffraction lines of are also similar to the 100004 diffraction line of graphite, suggesting that this compound has a graphite structure. FIG. 2 shows the IR spectrum of the compound of the present invention. The large band between 1650 and 1250 cm ^-1 is thought to be due to the stretching vibration of the triazine ring, and the band at 802 cm ^-1 is considered to be due to the bending vibration, which causes the triazine ring (six-membered C ₃ N ₃ ring) to decompose in the product. You can see that it remains without doing it. On the other hand, the band at 3180 cm ^-1 is N-H or C-
This is due to the stretching vibration of H, and in a part of the crystal,
This is thought to be caused by hydrogen bonding to carbon atoms in the triazine ring, or due to some nitrogen atoms not included in the triazine ring bonding to hydrogen atoms. FIG. 3 shows an ESCA spectrum measured using Mg-Kα rays, and a sharp and well-symmetrical peak at 287.8 eV was observed in the C _1S spectrum. This is on the higher energy side than graphite and contaminant carbon (284.6eV),
This means that the carbon atom loses an electron to an atom with high electronegativity, such as a nitride atom, and becomes positively charged. On the other hand, as shown in Figure 4, the presence of slightly negatively charged nitrogen (398.5 eV) and slightly different nitrogen (higher energy shoulder) was confirmed in the N _1S spectrum. The above results are
A structure consisting of two types of nitrogen atoms with different bonding states and a carbon atom with a single bonding state was estimated, and it was found that the structure agreed very well with the structure estimated by the present inventors. When the specific gravity of the compound of the present invention is measured, it is 1.6 to 1.8.
It was hot. Based on the structure estimated by the inventors,
Assuming that these crystals do not contain any defects or hydrogen atoms, their density is calculated to be 2.4.
g/cm ³ , but in fact, as can be seen from the results of X-ray diffraction, the crystal itself is close to amorphous.
Because it contains hydrogen atoms and also contains structural defects, its actual density is thought to be quite low. Another possible structure is that if the triazine ring is cross-linked with -NH-, the density will be less than 1 g/ ^cm3 , and the layers will be bonded in a zigzag manner in the C-axis direction without a layered structure. Considering this structure, its density would be 3.5 g/cm ³ , which is significantly different from the actual value. Next, the physical properties of the compound of the present invention will be described.
First, regarding thermal stability, Figure 6 shows the results of TG and differential thermal analysis (DTA) conducted in air. As you can see from this result, this compound has 390
It starts to thermally decompose around ℃ and undergoes oxidative decomposition, so
DTA shows a fever pattern. However, since it has much better heat resistance than general organic polymers, it has great potential as a substitute for organic polymers. On the other hand, measurements of the physical properties of the sublimate revealed that it simply sublimes in an inert atmosphere such as helium or nitrogen, but does not decompose until it reaches a fairly high temperature. This property can be used to form films on a variety of substrates by methods such as vacuum deposition. Figure 5 shows a film (0.15 μm) deposited on a quartz plate.
This is the UV spectrum of As can be seen from this figure, there is little absorption in most of the visible range from 430 to 900 nm, the transmittance decreases when the wavelength is smaller than 430 nm, and there is almost no transmission at 300 nm. Therefore, the deposited film becomes pale yellow and transparent. A major feature of this compound is that it exhibits fluorescent properties. FIGS. 7 and 8 show the fluorescence spectra of the compound powder of the present invention. Figures 7 and 8 show spectra when irradiated with light of wavelengths opposite to the excitation light of commonly used low-pressure mercury lamps and high-pressure mercury lamps, respectively. In the case of a lamp, the excitation light is 365 nm ultraviolet light.
As can be seen from the comparison of these two figures, in this case, the emission intensity is higher when excited at 365 nm.
In general, phosphors for fluorescent lamps emit light efficiently with light of 253.7 nm, and many phosphors, including calcium halophosphate, have been put into practical use. On the other hand, in addition to emitting light efficiently, phosphors for high-pressure mercury lamps are required to withstand use at high temperatures of 250 to 350 degrees Celsius. few. Among those that have been put into practical use, YVO ₄ :
Eu ³⁺ BaMg ₂ Al ₁₆ O ₂₇ : There are Eu ²⁺ and Mn ²⁺ , but both are expensive because they use expensive rare earth elements as activators. However, the compound of the present invention is stable in the atmosphere up to 400°C, is inexpensive, and can be deposited on metals, ceramics, polymers, glass, etc. in nitrogen or vacuum, so it has various applications. It is very useful as a fluorescent material. Table 2 shows the results of investigating the durability of the compounds of the present invention against solvents.As a method for determining durability, 0.3 g of the compounds of the present invention were added to 100 c.c. of each solvent, stirred for 12 hours, and then evaporated. , dried and weighed. As you can see, it is insoluble in commonly used solvents, but it becomes an emulsion in concentrated nitric acid or concentrated sulfuric acid, and can pass through a 1 μm filter. In addition, a compound film of the present invention was deposited on an aluminum plate and the electrical resistance of the film was measured.
At room temperature, the electrical resistance in the direction perpendicular to the film surface was 5×10 ¹⁰ Ωcm, and in the horizontal direction it was 3×10 ⁹ Ωcm, indicating that both were semiconductors. As mentioned above, the compounds of the present invention have various interesting physical properties. Among these, the fluorescent properties have specific uses as mentioned above. [Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Example 1 15 g of cyanuric chloride as a raw material was placed in the center of a device consisting of a glass tube with an inner diameter of 40 mm and a length of 1000 mm, and 50 c.c./cm of ammonia and nitrogen as a carrier gas were each placed.
After thoroughly mixing at a speed of 100 c.c./min and 100 c.c./min, the mixture was introduced into the tube. The pressure inside the tube was atmospheric pressure. After reacting for 1 hour under the above conditions, the center of the reaction tube was slowly heated at 1°C/min in an electric furnace.
The temperature was raised to 400°C and held at 400°C for 2 hours. After that, stop the ammonia and flow only nitrogen.
It was heated to 600°C and held at that temperature for an additional hour. Inside the reaction tube, yellowish white powder was produced at the location where the raw materials had been installed, and the amount was 5 g. This powder showed the property of subliming at temperatures above 400°C in a nitrogen stream. The results of elemental analysis of this compound are shown in Table 1. Further, X-ray diffraction measurements were performed using Cu-Kα rays, and the diffraction pattern shown in FIG. 1 was obtained. Furthermore, add 0.3 g of this compound to 100 c.c. of each solvent,
After stirring for a period of time, the mixture was filtered, dried, and weighed to determine its durability against solvents. The results are shown in Table 2. Example 2 Cyanuric chloride 60g, ammonia 100c.c./min,
The experiment was carried out under the same conditions as in Example 1 except that nitrogen was used at 100 c.c./min. After the reaction was carried out at 400°C, the ammonia supply was stopped, only nitrogen was flowed, and the temperature was heated to 500°C and maintained for 1 hour.
The color and properties of the obtained compound (23 g) were the same as those of the compound of Example 1, and the results of X-ray diffraction measurements were also almost the same. The results of elemental analysis are shown in Table 1. Example 3 In the same apparatus as in Example 1, 6 g of cyanuric chloride and 2 g of melamine were mixed and placed in the center of the reaction tube, and the temperature was slowly raised to 500°C at 1°C/min under nitrogen flow. Hold at temperature for 1 hour. The properties and X-ray diffraction results of the obtained compound (1 g) were almost the same as in Example 1. Example 4 The raw materials and the amounts of each gas were the same as in Example 1, and immediately after starting the introduction of ammonia gas at room temperature, the temperature was 10℃/
The temperature was raised to 200°C in minutes, and the reaction was carried out for 2 hours at that temperature, and then the temperature was further raised to 400°C, and the reaction was carried out for 1 hour.
After that, stop the ammonia, flow only nitrogen, and 600
℃ and held for 30 minutes. The color and properties of the obtained compound (5 g) are as in Example 1.
It was the same as the compound of The analytical values of this powder are shown in Table 1. Example 5 1 g of the powder obtained in Example 2 was placed in a quartz glass tube, and while nitrogen gas was flowing at 100 c.c./min,
The center of the reaction tube was heated to 700°C at 10°C/min using an electric furnace. When the temperature exceeds 400℃, sublimation begins,
It began to deposit in the form of a film and powder at the rear of the reaction tube.
The analytical values of this powder are shown in Table 1. Example 6 Using the same equipment as in Example 1, 45 g of cyanuric chloride was placed in a quartz reaction tube in front of the electric furnace, and while nitrogen gas was flowing at 50 c.c./min, the center of the reaction tube was heated.
Heated to 700°C. After that, the part where cyanuric chloride was placed was heated to 210°C at a rate of about 10°C/min using a ribbon heater, and ammonia gas was added.
Nitrogen gas was introduced into the reaction tube at a rate of 100 c.c./min and 200 c.c./min. Ammonia was introduced using a nozzle to cause a reaction inside the electric furnace. The pressure inside the tube was atmospheric pressure, and the reaction time was 3 hours. A film-like substance (thickness: 1 mm) was obtained inside the reaction tube near the entrance and exit of the electric furnace, and powder was obtained at the rear of the electric furnace. The analytical values of the compounds obtained by heat-treating this powder and film at 500°C are shown in Table 1 for Examples 6-1 and 6-2.
Shown as The physical properties of the compound of this example were the same as those of Example 1.

【table】

【table】

[Table] Judgment ○: Solvent resistant △: Questionable ×: No solvent resistant Example 7 Using the powder produced in Example 2, it was filled into a holder with a diameter of 10 mm and exposed to a high-pressure mercury lamp using a xenon lamp through a quartz glass window. is the excitation light of
It was irradiated with 365 nm light and its fluorescence spectrum was measured. The results are shown in FIG. This figure shows that the excitation light efficiently emits light with a wavelength of 465 nm, which corresponds to blue. Example 8 The powder produced in Example 1 was deposited on a glass plate in a nitrogen stream to obtain a translucent film. The thickness of the film is approximately 26 μm, with a range of 800 to 500 nm.
It showed a transmittance of over 30%. When the fluorescence spectrum of this film was measured in the same manner as in Example 7, it was found to be 465 nm as in Example 7.
Strong fluorescence was observed. [Effects of the Invention] The compound of the present invention is a completely new compound of nitrogen and carbon having an unprecedented new chemical composition and structure, and has excellent properties such as fluorescent properties, lubricating properties, and heat resistance properties.

[Brief explanation of the drawing]

FIG. 1 is an X-ray diffraction diagram of the compound of the present invention, and FIG. 2 is a diagram showing the IR spectrum of the compound of the present invention. 3 and 4 are ESCA spectra of the compound of the present invention, FIG. 3 is a spectrum for carbon, and FIG. 4 is a spectrum for nitrogen. Furthermore, FIG. 5 shows the UV spectrum of the compound, and FIG. 6 shows the spectra of TG and DTA. Figures 7 and 8 are spectra showing fluorescence characteristics. Figure 7 shows the spectrum when a low-pressure mercury lamp is irradiated with 253.7 nm light, which is the excitation light, and Figure 8 shows the spectrum when the excitation light of the high-pressure mercury lamp is irradiated. is light
This is the case when 365 nm light is irradiated.

Claims (1)

[Claims] 1 General formula C ₃ NxHy (where 4≦X≦5, 0≦
Carbon nitride having a layered structure represented by Y≦4). 2. A method for producing carbon nitride having a layered structure represented by the general formula C ₃ NxHy (4≦X≦5, 0≦Y≦4), which comprises reacting cyanuric chloride with ammonia or melamine. 3 General formula C ₃ NxHy (however, 4≦X≦5, 0≦
A fluorescent material made of carbon nitride and having a layered structure represented by Y≦4.