JPH04117409A - Continuous chlorination of paraffin - Google Patents

Abstract

PURPOSE:To produce a chlorinated paraffin it low cost by a simple process without using any solvent by continuously bringing a paraffin in a state of a wet film into contact with a chlorine gas under irradiation with light as a catalyst. CONSTITUTION:Hot water is passed through the jacket of a reaction zone, and cold water is passed through the jacket of a cooling zone. When a light source for a photochlorination catalyst is switched on and reaches a steady state of light emission, a paraffin wax liquefied by heating is fed to the reaction zone through a constant rate pump. When the fed paraffin wax is distributed on a distributor to form a wet film on the reaction zone and begins flowing downwardly, chlorine is fed to the zone through an inlet on the bottom, and the paraffin wax is allowed to react with the chlorine by countercurrent contact in the reaction zone. The formed chlorinated paraffin flows downwardly, is cooled in a cooling zone and is sent through a tube for measuring a specific gravity to a product tank. The formed hydrogen chloride gas and an unreacted chlorine gas are purged off as a waste gas from the top and sent to a tower for intoxication.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for chlorinating paraffin, which is characterized by continuously contacting paraffin with chlorine gas in a wet film state under irradiation with light, and a process for chlorinating this paraffin. The present invention relates to a preferred apparatus for carrying out the method.

(Conventional technology) Chlorinated paraffin has excellent electrical insulation and fire resistance.
It is used in fire-retardant coatings for ships, waterproof and fire-retardant coating agents for canvases, canopies, plasticizers for vinyl resins, lubricants (extreme pressure lubricants), etc. Chlorine content 40.45.50.65.7
0% is commercially available.

Conventionally, chlorinated paraffin has been produced by blowing chlorine gas into liquid paraffin to chlorinate it. However, since this method is a batch method, it is inefficient and difficult to control the production amount.

In particular, in the production of highly chlorinated paraffins with a chlorination rate of 70%, carbon tetrachloride or the like is used as a solvent to maintain the liquid state during the reaction process.

For this reason, a step of removing such a solvent after the completion of the reaction is required, which has been a factor in inhibiting production efficiency. Special Notice Showa 5
No. 2-43806 relates to a method for producing highly chlorinated paraffin, but in this method, the chlorination reaction is carried out in two steps, which is complicated, and in addition, a chlorinated hydrocarbon must be used as a solvent in the latter step.

(WR problem to be solved by the invention) In the state of the prior art, it is possible to produce chlorinated paraffin with high production efficiency, easy control of production amount, no solvent required, and simple process. Development of laws is required.

Incidentally, since the use of solvents such as carbon tetrachloride is prohibited worldwide, we have developed a method that can produce chlorinated paraffin at a low cost and with a quality comparable to that of conventional paraffin without using such solvents. There is a particular need for the development of

(Means for Solving the Problem) As a result of intensive research in search of a solution to the above problem, the present inventor has found that
The present invention has been completed which solves the above problems. That is, the present invention provides (a) a continuous chlorination method for paraffin characterized by continuously bringing paraffin into contact with chlorine gas in a wet film state under irradiation with catalyst light; (b) It has an exhaust gas outlet at the top of the column, a paraffin inlet at the top of the column, and a distributor that allows paraffin to flow down in a wet film state on the inner wall of the column, and chlorine at the bottom of the column. It has a paraffin extraction port, a chlorine inlet at the bottom of the tower, and divides the inside of the tower into two between the distributor and the chlorine inlet, with the upper part forming a reaction zone and the lower part forming a cooling zone. A reactor for the continuous chlorination of paraffins, characterized in that it is a reaction column each having a jacket for heat exchange so as to form a reactor for the continuous chlorination of paraffins, and such a chlorination process is defined by a preferred apparatus for carrying it out, (C) With the reaction zone of the above reactor under catalytic light irradiation and a heat exchange medium passed through both jackets of the reactor, paraffin is fed into the reaction column from the paraffin inlet of the reactor and is then passed through the distributor. By supplying chlorine into the reaction tower from the chlorine inlet while continuously flowing down the inner wall surface of the reaction tower in a wet film state, the wet film state is created by supplying chlorine into the reaction tower in gaseous form and continuously flowing down the inside of the reaction tower in a wet film state. The present invention relates to a continuous chlorination method for paraffin, which is characterized in that the paraffin is brought into contact with the paraffin, the generated hydrogen chloride gas and unreacted chlorine gas are extracted from an exhaust gas outlet, and the generated chlorinated paraffin is extracted from a chlorinated paraffin outlet.

Hereinafter, the present invention will be explained one by one.

The paraffins to be chlorinated by the method of the invention are liquid and solid paraffins at room temperature.

When paraffin is reacted with chlorine gas, if the paraffin is made into a wet film and is brought into continuous contact with chlorine gas while being irradiated with light as a catalyst, the reaction rate is high and the reaction rate is high for chlorine gas, and no solvent is required. The paraffin is chlorinated to the desired chlorine content without sacrificing it. As the irradiation light, both visible light and ultraviolet light can be used, but ultraviolet light is preferable from the viewpoint of catalytic activity. When using the method of the present invention, even when ultraviolet light is used as a catalyst, no adverse effect on the chlorinated paraffin obtained is observed ( I am using the cut one.

Such reaction conditions can be realized, for example, by using a reaction apparatus as shown in FIG.

To explain the reaction apparatus shown in FIG. 1, the wet wall column is a reaction column. It is called this because paraffin forms a wet film on the inner wall of the reaction tower and is caused to flow down continuously. Of course, in order to chlorinate solid paraffin, it must be made into a liquid state beforehand.

Of course, the material for the wall of the reaction tower must be one that allows the irradiated photocatalyst to pass through. For this reason and from the viewpoint of corrosion resistance, glass, especially "Pyrex" glass, can be used as the material.

A reaction zone is provided in the upper part of the reaction tower, and a cooling zone is provided in the lower part. The former is formed by attaching a jacket to the reaction tower, through which a heat exchange medium (for example, low-temperature water at 50° C.) for regulating the reaction temperature is circulated, and through which hot water is circulated. Since the light source is placed outside this jacket,
It goes without saying that the material of this jacket must also be able to transmit the irradiated light. In the cooling zone, a jacket is placed between the photocatalyst irradiation part and the chlorine inlet to allow a cooling heat exchange medium to pass through to prevent abnormal reactions such as ignition of the chlorinated paraffin produced due to the reaction temperature of the FA raw inlet part. It is formed by attaching it to a reaction tower and passing a cooling heat exchange medium (for example, cooling water such as tap water) through it.

Liquid paraffin or solid paraffin that has been heated and liquefied is fed into the reaction tower from the paraffin inlet near the top of the reaction tower. A suitable distributor is provided for flowing down in a wet film along the inner wall of the column. One example of such a distributor is the one shown in Figure 1, which has pores at the bottom of the paraffin receiver formed by the distributor wall and the inner wall of the reaction tower, and the paraffin that passes through this pore forms a wet film on the entire inner wall of the reaction tower and flows down. The holes were drilled at appropriate intervals.

The distributor can also be configured in the form of an overflow can, as shown in FIG. If the upper end of the reaction tower is made uneven, the paraffin overflowing from the overflow can will easily flow down while forming a wet film on the entire inner wall of the reaction tower. The distributor may be of any type as long as it allows paraffin to flow down the inner wall of the reaction column in the form of a wet film.

Hydrogen salt gas and unreacted chlorine gas produced by the reaction are discharged from the exhaust gas outlet at the top of the reaction tower and subjected to appropriate exhaust gas abatement treatment. An outlet for the produced chlorinated paraffin is provided at the bottom of the reaction tower.

A thermometer optionally inserted from the top of the column is for measuring the reaction temperature, and a thermometer optionally installed at the bottom of the cooling zone is for cooling effect N Tachikawa. A chlorinated paraffin product tank may also be optionally provided. It is also possible to provide a gas sampling device in the exhaust gas extraction pipe, and the reaction rate of chlorine can be determined by analyzing the sampled gas using this device.

The amount of paraffin supplied to the reaction tower can be measured, for example, through a metering pump, and the amount of chlorine supplied to the reaction tower can be measured, for example, with a float type flow meter.

In the reactor shown in FIG. 1, a wet film of liquid paraffin is only formed on the inner wall of the reaction tower, but the reaction can be carried out more efficiently by increasing the area of the wet film. In order to increase the wetted membrane area, for example, the inner wall of the reaction column may be formed into a corrugated plate shape.

In the reaction apparatus shown in FIG. 1, an external irradiation method is employed as a method of irradiating the photocatalyst. However, internal irradiation methods are also possible.

The internal irradiation method has the advantage of being able to directly irradiate the reaction surface with the photocatalyst from the light source, but it also has the disadvantages of manufacturing difficulties and the possibility that the mist generated during the reaction will adhere directly to the light source, making it impossible to fully utilize the photocatalyst. There are some disadvantages such as the fact that When carrying out the method of the present invention, it is preferable to select a photocatalyst irradiation method taking these points into consideration.

Although it will be obvious to those skilled in the art from the foregoing description that paraffin wax can be chlorinated using the reactor shown in FIG. 1, a few additional comments will be made.

To start chlorination, a suitable heat exchange medium at an appropriate temperature is passed through the jackets of both the reaction zone and the cooling zone in advance, and the light source for photocatalyst irradiation is turned on, and then the heated liquid paraffin is preferably quantified. The paraffin is continuously supplied to a distributor in the reaction tower via a pump, whereby the paraffin forms a wet film on the inner wall of the reaction tower and continuously flows down. On the other hand, chlorine, which is continuously fed into the reaction tower from the chlorine inlet at the bottom of the tower, rises in the tower in gaseous form and comes into contact with the wet film of paraffin in the reaction zone, thereby causing a chlorination reaction of paraffin. It is done continuously.

In general, when a chemical reaction is carried out using a catalyst, the reaction rate increases, but when a reaction tower is used as described above and one of the raw materials is subjected to the reaction in a wet film state flowing down, the reaction rate of this raw material is increased. Since the reaction must be completed within the short time it takes for the liquid to flow down the inner wall of the column, the aid of a catalyst must be used. However, regarding the impact caused by the catalyst mixed into the product, there are many unknowns in the case of chlorinated paraffin, which is the target product of the method of the present invention, so it is recommended to use light that does not remain in the product as a contaminant as a catalyst. has the advantage of avoiding this problem.

The chlorinated paraffin produced by the reaction is taken out from the outlet at the bottom of the reaction tower. Furthermore, simultaneously generated hydrogen chloride gas and unreacted chlorine gas are extracted from the top of the tower and subjected to excessive exhaust gas abatement treatment.

A plurality of reaction towers are used for high utilization of chlorine and other purposes, liquid paraffin is supplied in parallel to the plurality of reaction towers, and chlorine gas is passed through the reaction towers in series. The unreacted chlorine gas accompanied by the generated hydrogen chloride gas is passed through a hydrochloric acid absorption tower at an appropriate point, where the hydrochloric acid is recovered. In Figure 3,
A conceptual diagram of an example in which the method of the present invention is implemented using a plurality of reaction columns is shown.

The degree of chlorination (chlorine content) of paraffin, the quality of chlorinated paraffin, etc. are determined by adjusting the light source for photocatalyst (for example, adjusting the intensity of the light source in Fig. 1 or changing the light source) when using such a reaction tower. The degree of chlorination can also be adjusted by traversing multiple sections and adjusting the number of sections with the light source turned on), as it depends on the paraffin supply amount, chlorine supply amount, and reaction temperature. A person skilled in the art can easily focus on such factors and predetermine the necessary reaction conditions for a reaction apparatus to achieve a desired degree of chlorination through preliminary experiments. .

(Example) The present invention will be further explained below with reference to Examples.

Example 1 A “Pyrex” reactor with the shape shown in Figure 1 was used.
A glass wet wall tower was adopted. However, the inner diameter of the wet wall tower was 5α, the light source length was 180 cg+, the reaction zone length was 200 α, and the cooling zone length was 50 cm.

Solid paraffin (paraffin wax) subjected to chlorination
The number of carbon atoms was distributed from C16 to C4o, the average number of carbon atoms was C26, and the melting point was 53°C.

The outline of the reaction operation was as follows.

To start the reaction, first, warm water (approximately 50°C) is passed through the reaction zone jacket, and then cooled! Tap water was passed through the in-zone jugget. When the photocatalytic light source was turned on and a steady state of light emission was achieved, paraffin wax, which had been heated and liquefied, was supplied by a constant pump. When the supplied paraffin wax was dispersed by the distributor, forming a wet film in the reaction zone and began to flow down, chlorine was supplied from the lower inlet, and the paraffin wax and chlorine were brought into countercurrent contact within the reaction zone, causing a reaction.

The produced chlorinated paraffin flowed down, was cooled in a cooling zone, passed through a specific gravity measuring tube, and was then sent to a product tank. On the other hand, the generated hydrogen chloride gas and unreacted chlorine gas were pushed out from the top as exhaust gas and sent to the abatement treatment tower.

During the operation, the paraffin wax flowed uniformly down the inner wall of the wet wall tower, and no drift was observed.

In the reaction zone, the bubbling phenomenon was noticeable from the lower part of the light irradiation area to about 50 mm. This part is the part where the reaction is most intense, and the generated chlorinated paraffin reaches a maximum temperature of 1
In some cases, the temperature reached 60°C, but because it was rapidly cooled in the cooling zone, the temperature dropped to 35°C after passing through the cooling zone.

Therefore, no abnormal phenomena such as ignition were observed around the chlorine inlet.

Details of the reaction conditions are shown in Table 1.

Part 1 table Wave length (person) Output power (W, light) Irradiation tower chief C+v+) Irradiation distance (dark) Wet wall tower supply amount (g/min) paraffin chlorine 3000~4000 40wx4 lights 51.0 81.3 Nainao, see below.

The reaction results are shown in Table 2 along with the quality of the chlorinated paraffin obtained. For comparison, similar data on chlorinated paraffins produced by the conventional batch chlorination method are also listed in Table 2.

Table: Bunch chlorination method of the present invention Chlorinated paraffin production, 1i (per 5 minutes) 419 specific gravity (
70℃＞1.124
1.124 Chlorine-containing haze (%) 41
．． 0 41.0 Chlorine reaction rate (%)
&3.4 Quality color of chlorinated paraffin <APHA> 55
130! i! Ii
O,020,02 refractive index (25℃>
1.503 1.503 Thermal stability (17
5℃, N2 blower) HC removal (%) (4 hour value) 0.128
0.140 Volatilization loss (%) 0.
167 0.171 Hue before and after heating
Pale yellow → brown Pale yellow → dark brown Gear oven heat coloring (120℃ x 2h, 150℃ x 3h) Pale yellow → brown Pale yellow → black brown Weather resistance Taiko light 7 days after cloud haze Hue Pale yellow → brown Pale yellow → reddish brown By the way, this book The inventor has obtained various findings by conducting the same experiment as in Example 1 by changing the reaction conditions. This will be explained below.

(1) Photocatalytic photochemical reactions for chlorination generally utilize light energy in a specific wavelength range, and the selection of effective wavelength is the most important issue. The effective wavelength of light used for chlorination is generally considered to be in the range from ultraviolet to visible light. The present inventor also acknowledges from past knowledge that wavelengths in this range are extremely effective for the chlorination reaction of paraffin, but also acknowledges that it also has an adverse effect on the quality of the chlorinated paraffin product. . Therefore, the minimum necessary condition for determining whether a commonly used light source can be used for this reaction is that the quality of the product does not deteriorate due to the use of a photocatalyst. Light sources commonly used for photochlorination include hydrogen discharge tubes, flash lamps, mercury lamps, and tungsten lamps.

Xenon lamps, halogen lamps, special fluorescent lamps, etc. are known.

Therefore, in making the present invention, various light sources for photocatalysts were collected.To give an example, a fluorescent lamp for copying has an emission peak at 4,050 yen, and a wavelength range of 340 yen.
It is widely distributed between 0 and 4,600 people.

Since this corresponds to the spectral sensitivity of diazo-sensitive paper, it is used as a light source for copying machines. UV output 14w/
90w tube. ;Light Source B - A halogen lamp that emits white light by enclosing a halogen compound, and has a wide range of uses for general lighting. Ultraviolet II is not small. : Light source C - Fluorescent lamp, the emission peak is at 5300, and the wavelength range is 4700 ~
It is distributed over 6,200 people. Contains no ultraviolet rays. It has applications for copying machines and photochemistry. ;The light source is a fluorescent lamp, and the wavelength range is distributed over 3,000 to 5,800 people. Emits blue light. It has uses for stage lighting and photochemistry. :Light source E - Fluorescent lamp, the emission peak is at 3,600 yen, and the wavelength range is from 3,000 yen to visible light. It has uses for insect traps and photochemistry. Ultraviolet delivery cuff, 5w/40w tube. ;Light source F - fluorescent lamp;
The luminescence peak is at 3600, and the wavelength range is 30.
The distribution ranges from 00 to 4000 people. No visible light is emitted. It has uses for fluorescence inspection and photochemistry, ultraviolet clay cuff, 5w/40w tube; light source G - high pressure mercury lamp,
It has photochemical applications in the wavelength range of 2,500 to infrared. Light Source H - A mercury lamp for illumination, for general illumination, with a wavelength range of 2,500 to infrared.

Incidentally, the light source used in Example 1 is light source F of the above-mentioned light sources.

■ Quality of chlorinated paraffins produced with various photocatalysts The reaction apparatus of Example 1 was used in the same manner as in Example 1, except that various light sources were used as photocatalysts and chlorine-containing @41.
We prepared 0% chlorinated paraffin and confirmed whether the photocatalyst had any effect on quality.

The sample for the quality test was taken directly from the specific gravity measuring tube in the reaction room, 4% anhydrous soda carbonate was added thereto, and air blowing was carried out while stirring for 2 hours. After that, 1% stabilizer was added, and the sample was filtered and used as an analysis sample.

The results were as follows. [a) Regarding the hue, the hue of the chlorinated paraffin according to the invention was superior to the control amount. (b) Regarding acid value and refractive index, the chlorinated paraffin according to the present invention was equivalent to the control amount, and no abnormality was observed. (C) Regarding thermal stability (175°C, N2 blower), when test sample 259 was put into a flask and subjected to a thermal stability test in which N2 blower was applied while keeping it at 175°C in an oil bath, it was found that the product according to the present invention The thermal stability of was better than the control amount. Further, the volatilization loss was the same as that of the control amount, and as for the hue after heating, the control amount was colored blackish brown, but the amount of photochlorination according to the present invention was all brown, which was very excellent. (d) Heat coloring test results by gear open: In order to determine minute differences in heat resistance (thermal coloring) of chlorinated paraffin, test samples were heated in a gear oven at 120°C for 2 hours and at 150°C for 3 hours. When heated, the control sample was markedly colored and turned blackish brown, but among the amounts of photochlorination according to the present invention, the product was brown except for the product due to the light source, which was colored reddish brown, and was excellent.

(e) Weather resistance test results showed that when the test sample was placed in a hue measuring glass cylinder and exposed to sunlight outdoors for 7 days, the control amount was markedly colored and turned reddish brown, but the photochlorination amount of the present invention was Among them, the products irradiated with light source A@ and the products irradiated with light source were colored brown, but the products irradiated with other light were colored brown, and their weather resistance was extremely excellent.

O) Effect of light source on quality (a) Regarding specific gravity, acid value, refractive index and chlorine content,
The specific gravity, acid value, refractive index, chlorine content Φ, etc. of the chlorinated paraffin measured by eight types of light sources were exactly the same as the control amount, and no difference was observed. From this, it is determined that the chlorinated paraffin produced by the reaction method of the present invention and the control amount are the same product. (b) Regarding hue, thermal stability, and weather resistance, the hue, thermal stability, and weather resistance of chlorinated paraffin produced when irradiated with ultraviolet rays in a general manufacturing method for chlorinated paraffin generally tend to be poor. This is said to be because the product has an unstable structure that is susceptible to dehydrochlorination, as chlorine activated by ultraviolet light also substitutes in unstable positions in the molecule. However, the color, thermal stability, and light resistance of the products produced by the reaction method of the present invention were superior to those produced by the conventional production method. Possible reasons for this are (a) The reaction is completed in a very short time, so the thermal history is very short.

This is probably because the time for thermal decomposition during the reaction is extremely short. (b) This is probably because the reaction surface area is large due to the membrane surface reaction, and the activated chlorine molecules react preferentially to positions where the reaction is more likely to occur. On the contrary, this is thought to result in a stable structure due to the substitution at a position that is difficult to decompose.

(4) Differences in chlorine reaction rate depending on the type of light source In order to strictly compare and examine the difference in chlorine reaction rate depending on the type of light source, conditions were selected so that the chlorine content of the chlorinated paraffin produced was almost the same. I went.

The chlorine reaction rate for each light source was calculated from the amount of chlorine used, the amount of paraffin supplied, and the chlorine content of the chlorinated paraffin produced. The material balance was calculated from chlorine content, paraffin supply Φ, specific gravity of chlorinated paraffin produced, and amount of chlorinated paraffin produced. These results were good.

Among the eight divine light sources used in the experiment, light sources D, E, and F
The catalytic effect was excellent. This difference in superiority is thought to be caused by differences in wavelength distribution and irradiation tower length.

(Effects of the Invention) The present invention provides a method for producing chlorinated paraffins that has good production efficiency, allows easy adjustment of production amount, does not require a solvent, and includes a simple process. In addition, it has become possible to produce chlorinated paraffin at low cost without using a solvent such as carbon tetrachloride, that is, without using a solvent, and whose quality is at least as good as that of conventional paraffins.

[Brief explanation of drawings]

Figure 1 shows an example of a reaction tower according to the present invention, Figure 2 shows an example of an overflow can type distributor, and Figure 3 shows an example of connecting reaction towers when a plurality of reaction towers are used. show.

Claims (3)

[Claims] (1) A continuous chlorine ratio method for paraffin, which is characterized in that paraffin is brought into continuous contact with chlorine gas in a wet film state under irradiation with catalyst light. (2) It has an exhaust gas outlet at the top of the column, a paraffin inlet at the top of the column and a distributor that allows paraffin to flow down in a wet film over the inner wall of the column, and a chlorinated paraffin outlet at the bottom of the column. , has a chlorine inlet at the bottom of the column, and divides the inside of the column into two between the distributor and the chlorine inlet, so that the upper part forms a reaction zone and the lower part forms a cooling zone. A reaction apparatus for continuous chlorination of paraffins, characterized in that the reaction tower has a heat exchange jacket. (3) With the reaction zone of the reactor according to claim 2 under irradiation with catalytic light and with a heat exchange medium passed through both jackets of the reactor, paraffin is supplied into the reaction tower from the paraffin inlet of the reactor. The chlorine is then continuously flowed down as a wet film on the inner wall of the reaction tower via a distributor, and chlorine is supplied into the reaction tower from the chlorine inlet, and the gas is allowed to rise continuously inside the reaction tower. A continuous chlorine ratio method for paraffin, which is characterized in that the paraffin is brought into contact with the paraffin in a wet film state, during which time generated hydrogen chloride gas and unreacted chlorine gas are extracted from an exhaust gas outlet, and generated chlorinated paraffin is extracted from a chlorinated paraffin outlet. .