KR101328259B1 - A method for Continual Nitration from Alkanol - Google Patents

Abstract

The present invention relates to an apparatus for nitrating reaction of alkanol and a method for continuous nitration of alkanol using the same, a tubular reactor having a spiral continuous member installed therein and a circulating heat exchanger for controlling excessive heat generated during the reaction. The part is connected, and the reaction liquid is circulated by the circulating pump in the tubular reactor and the circulating heat exchanger, and by-products and the like can be removed as wastewater by neutralization reaction in the oil / water separator connected to the reactor. Nitration reaction apparatus of alkanol. And a continuous nitration of the alkanol consists of reacting the alkanol and acid mixture in the reactor. The reaction temperature is preferably controlled within the range of 30 to 45 ° C. due to the circulating heat exchanger.

Alkanol, nitration, tubular reactor, heat exchanger, circulation pump

Description

A method for continual nitration from Alkanol

The present invention relates to a method of continuous nitration of alkanols, and more particularly, to a method of continuous nitration of alkanols using a nitration reaction apparatus of alkanols using a tubular reactor and a circulating heat exchanger.

In general, nitric acid is known to generate a relatively small amount of heat in the nitration reaction, which reacts with alkanols to form nitrates (about 7 Kcal / mol). At this time, the presence of nitrous acid not only catalyzes the alkanol oxidation of nitric acid, but also generates excess heat by reacting with alkanol as an addition reaction (120-1,000 Kcal / mol). Therefore, it is important to avoid excessive heat generation in view of minimizing energy requirements and ensuring stable operating conditions.

In addition to the addition of alkanol, nitrous acid must be completely removed and must be removed each time it is formed during the reaction. In this case, a stabilizer such as urea is known to react with nitrite about 10 times faster than nitric acid. However, urea is also known to react with nitric acid to generate heat of about 65-87 Kcal / mol depending on the strength of nitric acid. In view of this thermal contribution, the stabilizer should be used in the minimum amount as much as possible.

In view of these considerations, U.S. Patent No. 5,162,568, as a prior patent, discloses a process for nitrating alkanols containing 5 to 13 carbon atoms, 20-30% nitric acid, 55-60% sulfuric acid, and 15-20%. Prepare a mixed acid mixed with water, adjust the temperature to 15-45 ° C. and then add a stabilizer selected from the group consisting of 2-5% of urea, sulfamic acid and hydrazine compared to the mixed acid at 15-45 ° C. It has been demonstrated that a process of mixing with alkanol yields 97% yield of 2-ethylhexyl nitrate (see Examples). However, the patent has a disadvantage in that the reaction time is long because the nitration reaction takes about 150 minutes by adding a small amount of alkanol as a raw material in order to stably control the reaction heat.

In this prior art, the reaction was carried out using a jacketed reactor. Specifically, as shown in Figure 4, a jacket-type reactor including a plurality of stirrers to assist the reaction therein, a aging tank connected to the reactor, a low boiling point material distillation column connected to the aging tank, and the aging A neutralizer supply tank connected to a pipe connecting a tank and the low boiling point material removal column, a high boiling point material removal column connected to an upper side of the low boiling point material removal column, and a high boiling point material removal column. And a branch pipe which separates the generated oily component and the aqueous wastewater component to the outside separately, and adducts and the like are removed through the pipe.

Here, the upper part of the jacketed reactor is connected to the pipe so that the raw material can be continuously supplied into the reactor. This pipe is injected with a calculated amount of 2-ethylhexanol and mixed acid into the reactor, respectively or mixed.

However, the process or apparatus also has a limit in controlling the heat of reaction, there is a limit in increasing the raw material input speed, there is a problem such as requiring a long reaction time. As a result, the reactor volume has been increased, but there is a limit as well, so it is difficult to continuously proceed with the nitration process from alkanol, so it is urgent to develop a technology capable of mass production.

In order to solve the problems of the prior art as described above, the present inventors continue to study to perform the nitration process from alkanol continuously, using a reactor equipped with a tubular reactor and a circulating heat exchanger The present invention has been completed based on the fact that it is possible to effectively control the excessive heat generated during the reaction and to achieve the nitration process continuously from the alkanol.

That is, an object of the present invention is equipped with a circulating heat exchanger that can effectively control the reaction heat generated during nitration reaction and a tubular reactor that can improve the reaction rate, nitro of alkanol suitable for mass production and economical In preparing a nitrated alkanol by using a sintering device, it is an object of the present invention to provide a continuous nitration method of alkanol that can easily adjust the raw material input and shorten the reaction time.

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In order to achieve the above object, the nitration reaction apparatus of alkanol according to the present invention,

A tubular reactor having a spiral rotating member having a pitch repeatedly formed therein along the length direction; A circulation heat exchanger connected to one end of the reactor and configured to control the supplied reaction liquid to a desired reaction temperature; A circulation pump connected between the circulation heat exchanger and the other end of the tubular reactor; And connected to the rear end of the reactor, receiving the crude reaction liquid produced in the reactor and the circulating heat exchanger is separated from the oil component and the water component by a neutralizing agent to recover the oil component, the oil water separator for discharging waste water components ; .

In addition, the method of continuous nitration of alkanol according to the present invention,

Including the alkanol nitration reaction apparatus described above, and injecting and reacting the alkanol and acid mixture in a mixed state in a tubular reactor; Circulating the crude nitrated alkanol reaction solution produced in the step, but circulating while controlling heat in a circulating heat exchanger; And mixing the neutralizing agent with the nitrated alkanol reaction solution circulated in the step, separating the oil component and the moisture component, and obtaining a nitrated alkanol from the oil component. .

Hereinafter, the present invention will be described in detail.

The present invention relates to a device for nitrating using alkanol and mixed acid as a raw material, and a method for continuously nitrating using the same. It is characterized by using a tubular reactor that can improve the.

The reactor according to the present invention is a reactor suitable for effectively controlling the heat of reaction and performing a large amount of nitration of alkanol, and reacting with a tubular reactor having a spirally rotating member having a pitch repeatedly formed along a longitudinal direction therein. Part of the circulating heat exchanger which controls excessively generated heat is connected, and the reaction liquid is circulated by the circulation pump under the reactor and the circulating heat exchanger, and by-products are neutralized in the oil / water separator connected to the reactor. Loop type separated as oil component or removed as waste water Reactor. The shape of the spiral continuous member is more preferable in view of the reaction efficiency that the rotation angle of the connecting portion between the pitch front end and the rear end is staggered by 90 °.

In more detail with reference to Figure 1, the nitrating reaction apparatus of the alkanol of the present invention is a tubular reactor (1) having a spiral rotating member 15 is formed with a repeated pitch (15a) in the longitudinal direction therein; , Connected to one end of the reactor (1) via a pipe (3), equipped with a circulating heat exchanger (4) for controlling the supplied reaction liquid to the desired reaction temperature, and the heat exchanger (4) in the reactor (1) A circulating pump (2) connected to the other end of the tubular reactor and installed at the rear end of the reactor (1) so that the reaction liquid is circulated, and generated in the reactor (1) and the circulating heat exchanger (4). It is provided with a crude reaction solution to separate the oil component and the water component by a neutralizing agent to recover the oil component, and includes an oil-water separator 12 for discharging the waste water component.

Here, the upper portion of the reactor 1 is connected to the raw material supply pipe 8 so that the raw material can be continuously supplied into the inside of the reactor 1. This feed pipe 8 continuously injects the calculated amount of alkanol and acid mixture into the reactor 1 in a mixed state.

The operation of the reactor according to the present invention configured as described above is as follows.

First, the alkanol and acid mixture is introduced into the reactor 1 in a mixed state. Then, a chemical reaction occurs inside the reactor 1, and the reaction liquid is accumulated in the reactor 1 while raising the water level.

When the amount of the reaction liquid in the reactor 1 is a predetermined amount or more, the reaction liquid is circulated through the reactor 1, the pipe 3, and the heat exchanger 4 by using the circulation pump 2. While the reaction solution is circulated, the reaction time is controlled by using the heat exchanger 4 to shorten the reaction time, and the raw material input amount can be easily adjusted.

The crude reaction liquids temperature controlled by the tubular reactor 1 or the circulating heat exchanger 4 are introduced into the oil / water separator 12 together with the neutralizing agents supplied from the neutralizing agent supply tank 10 through the pipe 9. The neutralization reaction separates the oily component and the aqueous component, and is withdrawn through the pipes 13 and 14, respectively. At this time, the oily component taken out from the upper layer becomes the nitration product of alkanol.

In particular, the tubular reactor 1 used at this time is not limited thereto, but referring to FIGS. 2 and 3, the inner diameter of the tube is a 1/4 inch tube having a 4.59 mm diameter, and the pitch 15a is 8.5 mm long therein. A tubular reactor having a helical rotating member 15 having 34 unit pitches within a diameter of 29 cm of the tubular reactor 1 and formed in the longitudinal direction of the reactor, and having a thickness (element thickness) of the helical rotating member being 0.55 mm. Preference is given to using. In particular, it is preferable that the ratio of pitch length to tube inner diameter is 1.5 to 2.0.

Here, the helical rotating member 15 is provided in the reactor 1 in the number of the one in the present invention, the helical rotating member 15 is connected to a drive motor (not shown) to provide power therefrom. Can be configured to rotate. This spiral rotating member 15 agitates the raw material in the liquid state, and the reaction liquids generated from the reaction solution are led to the circulating heat exchanger 4 by the circulation pump 2.

As shown in FIG. 3, the helical rotating member 15 includes a plurality of helical rotating members which repeatedly form a pitch 15a having a constant interval or a different interval as necessary along the longitudinal direction of the reactor 1. It may be provided, the connection portion before and after each pitch is advantageously staggered to 90 °, the structure of this spiral rotating member is increased by the reaction rate of the reaction solution or the reaction solution provided into the reactor (1) to react Increasing the efficiency and minimizing the temperature gradient inside the reactor can help control the heat of reaction.

The nitrated alkanol reactant can be produced in large quantities and economically using the nitration reaction apparatus of alkanol as described above and the continuous nitration method of alkanol using the same.

As the alkanol to be added to the present invention, it is preferable to use a kind having 5 to 13 carbon atoms, most preferably 2-ethyl hexanol.

In addition, as the acid mixture, it is preferable to use an appropriate amount of an acid, a stabilizer, and water including nitric acid, and as illustrated in the following examples, it is preferable to combine nitric acid and sulfuric acid as the acid containing nitric acid. In particular, it is preferable to mix nitric acid and sulfuric acid in a 1: 2 weight ratio in view of the reaction yield.

As the stabilizer, it is preferable to add one selected from the group consisting of urea, sulfamic acid and hydrazine, thereby achieving stability of the reaction. Since the stabilizer is used to remove nitrous acid present in the raw material, it is related to the purity of the raw material, but it is generally preferred to use 1.0 to 3.0% by weight based on the total weight of the acid mixture. In addition, it is preferable to mix the heat of reaction uniformly and to use the remainder of water in view of the reaction heat dispersion effect.

These nitric acid-containing acids, stabilizers and water are mixed and then the alkanols are blended. The injection conditions are 25 ° C without additional temperature control equipment. It is preferable because it can be injected under.

The reaction temperature in the tubular reactor is 30 to 45 ℃, the reactant residence time is preferably 2 to 3 minutes in view of the reaction efficiency. In addition, the circulation pump setting conditions are not limited to this, but 367 g / min at 45 ℃ It is characterized by the flow rate.

Further, the circulating heat exchanger may use a plate or shell and tube heat exchanger, it characterized in that the reaction liquid is maintained at about 30-45 ℃.

In addition, as a neutralizing agent for carrying out the neutralization reaction in the oil / water separator 11 of the present invention, a mixed solution of sodium sulfate (Na ₂ SO ₄ ) and sodium carbonate (Na ₂ CO ₃ ) is used, and the mixing ratio is 10% sodium sulfate. In the case of using sodium carbonate with a weight ratio of 4: 1 to 5: 1, it is preferable in view of the efficiency of the reaction. At this time, the sulfuric acid used as the reaction catalyst is neutralized with the sodium sulfate and converted into a salt to be removed into an aqueous layer.

The method for continuously nitrating the alkanol according to the present invention comprises the above-described nitration reaction apparatus of alkanol, and then mixing the alkanol and mixed acid mixture in a tubular reactor at 25 ° C. Injecting into the reactor and reacting for 3 minutes, circulating the crude nitrated alkanol reaction solution produced in the step, circulating while controlling heat in a circulating heat exchanger, and circulating nitro in the step Mixing the neutralizing agent with the converted alkanol reaction solution to separate the oil component and the water component, and collecting only the oil components among the separated components.

At this time, it is preferable to use a kind having 5 to 13 carbon atoms as the alkanol to be used in the present invention, and it is particularly preferable to use 2-ethyl hexanol.

In addition, the acid mixture is preferably used by mixing an appropriate amount of acid, stabilizer and water containing nitric acid, as it is clear in the following examples, the acid containing nitric acid is to combine nitric acid and sulfuric acid In particular, it is preferable to mix nitric acid and sulfuric acid in a 1: 2 weight ratio in view of reactivity.

As the stabilizer, it is preferable to add one selected from the group consisting of urea, sulfamic acid and hydrazine, thereby achieving stability of the reaction. The amount of the stabilizer is preferably 1.0 to 3.0% by weight based on the total weight of the acid mixture in consideration of the thermal contribution to the nitration reaction.

In addition, it is preferable to use water in the remainder of the balance, in consideration of the reaction heat dissipation effect uniformly mixed with the reactants.

The acid, stabilizer and water containing such nitric acid are mixed and then alkanol is mixed with them, and the injection conditions are preferably injected at 25 ° C.

In particular, the step of circulating while controlling the heat in the circulating heat exchanger is a step of controlling the temperature by allowing the reaction liquid to pass through the circulating heat exchanger, the control temperature is about 10 to 50 ℃ suitable. At this time, the crude reaction solution generated in whole or in part is refluxed to the reactor or moved to the oil / water separator, and is separated out after separating the oily component and the aqueous component by the neutralizing agent.

In this case, a mixture of sodium sulfate and sodium carbonate is used as a neutralizing agent, and the mixing ratio is preferably used in a weight ratio of 4: 1 to 5: 1 when using 10% sodium sulfate and sodium carbonate. On the other hand, the final reactant taken out is a pure nitrated alkanol reactant with a purity of 99.7%.

Typical schemes relating to the reaction process devised in the present invention can be represented as in Schemes 1 and 2 below.

As described above, in the reaction apparatus and the manufacturing method according to the present invention, in nitrating alkanols, a cyclic heat exchanger capable of effectively controlling the reaction heat generated during the nitration reaction and a tubular reactor capable of shortening the reaction time Equipped with, to provide a nitration production apparatus of alkanol suitable for mass production and economical, by using the nitration production apparatus of alkanol described above, it is easy to adjust the input amount of the raw material and nitration while reducing the reaction time Prepared alkanols can be produced economically and continuously.

Example  One

In order to produce nitrated alkanols using the reactor shown in FIG. 1, an acid mixture containing 23.4 wt% nitric acid, 56.4 wt% sulfuric acid, and 17.2 wt% wheat urea 3.0 wt% was fed while maintaining 25 ° C. The feed tank (2-ethylhexanol, 2-EH) having a purity of 99% as alkanol was supplied to the pipe 7 at a flow rate of 1.1 g / min through the tank 6 while maintaining 25 ° C. 5) through a flow rate of 0.4 g / min into the pipe 8 and mixed with the acid mixture supplied through the pipe 7 described above, 1/4 inch with a tube inner diameter of 4.59 mm and a total diameter of 29 cm. As a tube 34 pitches 15a of 8.5 mm in length are provided with a spiral rotating member 15 formed therein in the longitudinal direction, and continuous in a tubular reactor 1 having a thickness (element thickness) of 0.55 mm. Injected into. The tubular reactor used was Koflo company Stratos pat no 1 / 4-34.

The reaction temperature in the reactor 1 was 45 ° C., the reaction pressure was atmospheric pressure, and the reactant residence time was 3 minutes. Then, the flow rate of the reaction liquid circulated by the circulation pump connected to the other end of the reactor 1 was maintained at 367 g / min. The reaction temperature in the circulation pump 2 was 45 ° C.

The reaction liquid supplied into the circulation heat exchanger 4 through the pipe 3 to control the reaction heat is sequentially circulated through the reactor 1, the circulation pump 2, and the heat exchanger 4. Some of the crude 2-ethylhexyl nitrate reaction solution was fed through a pipe 9 into the oil separator 12 maintained at 45 ° C. at a flow rate of 1.5 g / min.

The reaction temperature in the oil / water separator 12 was 45 ° C., and the reaction time was 20 minutes at atmospheric pressure.

The pipe (9) is supplied through a pipe (11) from a neutralizing agent supply tank (10) separately provided, while maintaining a neutralizing agent mixed with 85.7% by weight 10% sodium sulfate aqueous solution and 14.3% by weight 10% sodium carbonate aqueous solution The neutralization reaction was carried out in the oil / water separator 12 by constant supply at a flow rate of 0.2 g / min.

The upper organic layer and the lower water layer separated by the neutralization reaction in the oil / water separator 12 were taken out at flow rates of 0.5 g / min and 1.2 g / min through the pipes 13 and 14, respectively.

The reaction proceeded continuously under the same conditions for more than 8 hours, the gas chromatograph analysis of the organic layer component, the purity of the final reactant 2-ethylhexyl nitrate (2-EHN) is 99.5%, yield ( Yield) was 99.6% by weight, not only to obtain high purity products but also to confirm that the majority of the feedstocks participated in the reaction. The experiments are summarized in Table 1 below:

step Raw material Temperature
(℃) flux
(g / min) Residence time
(minute) water
(%) flow g / min Moles / min Acid mixture supply Acid mixture 25 1.1 - - 1.1 0.02 2-EH Supply 2-EH 25 0.4 3.0 99 0.4 0.00 Circulating pump flow rate - 45 367 - - - - Oil Separator Supply - 45 1.5 - - 1.5 0.0 Neutralizer supply corrector 25 0.2 - - 0.0 0.000 Organic layer separation 2-EHN - 0.5 - 99.5 0.5 0.003 Water layer separation Wastewater - 0.2 - - - - Sum 1.7 yield(%) 99.6

As described above, in the embodiment using the reaction apparatus of the present invention having a tubular reactor and a heat exchanger, by controlling the reaction heat generated in the nitrification of the alkanol effectively, the reaction is completed in 3 minutes, thereby effectively controlling the raw material input amount. Since it is easy to carry out, it was confirmed that not only the continuous process was possible but also the reaction time was shortened.

On the other hand, when using the reactor having a jacket-type reactor of Figure 4 to maintain the reaction for 150 minutes in order to control the heat of reaction, when applying the same conditions as the present invention can not effectively control the reaction heat is limited in the raw material input rate there was.

1 is a schematic view of a reaction apparatus with a tubular reactor 1 and a circulating heat exchanger 4 according to the invention.

FIG. 2 is a perspective view of the tubular reactor 1 shown in FIG. 1.

FIG. 3 is an enlarged view of the inside of the spiral rotating member 15 having a constant interval of the pitch 15a in the tubular reactor 1 shown in FIG. 2.

Figure 4 is a block diagram showing a reaction apparatus having a low boiling point distillation column and a high boiling point distillation column according to the prior art, respectively.

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* Description of Major Symbols in Drawings *

1: tubular reactor

2: circulating pump

3,7,9,11,13,14: pipe

4: circulating heat exchanger

5: alkanol feed tank

6: acid mixture feed tank

10: neutralizer supply tank

12: oil-water separator

15: spiral rotating member

15a: pitch

Claims (10)

delete delete delete delete A tubular reactor having a spirally rotated member, the pitch of which is staggered at an angle of 90 ° in the longitudinal direction, and the ratio of pitch length to tube inner diameter is in the range of 1.5 to 2.0; A circulation type heat exchanger connected to one end of the tubular reactor and configured to control the supplied reaction liquid to a desired reaction temperature; A circulation pump connected between the circulation heat exchanger and the other end of the tubular reactor; And connected to the rear end of the tubular reactor, receiving the crude reaction liquid produced in the reactor and the circulating heat exchanger is separated from the oil component and the water component by a neutralizing agent to recover the oil component, drainage water to discharge the waste water component Separator; After the nitration reaction apparatus of the alkanol comprising a; injecting the alkanol and acid mixture in a mixed state in a tubular reactor and reacting under a reaction residence time of 2 to 3 minutes at a reaction temperature of 30 to 45 ℃; Circulating the crude nitrated alkanol reaction solution produced in the step, but circulating while controlling heat in a circulating heat exchanger; And Mixing a neutralizing agent with the circulated nitrated alkanol reaction solution, separating the oil component and the moisture component, and obtaining a nitrated alkanol from the oil component; Continuous nitration method of alkanol comprising a. 6. The method of claim 5, Wherein said alkanol has from 5 to 13 carbon atoms. 6. The method of claim 5, The acid mixture is made of nitric acid, sulfuric acid, water and a stabilizer, the nitric acid and sulfuric acid is mixed in a 1: 2 weight ratio method of continuous nitration of alkanol. The method of claim 7, wherein And said stabilizer is selected from the group consisting of urea, sulfamic acid and hydrazine. 6. The method of claim 5, The temperature range controlled in the circulating heat exchanger is a continuous nitration method of alkanol, characterized in that 10 to 50 ℃. 6. The method of claim 5, The neutralizing agent is administered with a mixture of sodium sulfate (Na ₂ SO ₄ ) and sodium carbonate (Na ₂ CO ₃ ), The sodium sulfate and sodium carbonate is a continuous nitration method of alkanol, characterized in that mixed in a weight ratio of 5: 1 to 4: 1.

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