JPS6010023B2 - Manufacturing method of iminodiacetonitrile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the field of production of iminodiacetonitrile (IDAN).

More particularly, the present invention relates to a process for producing IDAN by reacting hexamethylenetetramine, formaldehyde and HCN in an aqueous reaction medium (aqueous reaction mixture). More particularly, the present invention relates to a continuous method of producing IDAN by passing the aqueous reaction mixture through a continuous reaction zone (eg, a tubular reactor, continuous overflow autoclave, etc.). More than eight years ago it was reported that lOAN could be obtained in unspecified yields by reacting hydrogen cyanide with HMTA.

Eschweiler, Inn. , 278 229-23
9 (1894). Later in 1921 D rib skye
tal, bee r. , 54, 2659 confirmed that IDAN can be produced by the reaction of HMTA with an aqueous solution of hydrogen cyanide. In 1957, Miller, U.S. Pat.
disclosed that it can be produced with a yield of .

Recently, Saunde et al.
, 580, an acid-stabilized formaldehyde and hydrogen cyanide mixture and ammonia were prepared using a continuous reaction zone (tubular reactor) at carefully controlled ratios and temperatures of the reactants and at a pH greater than 7. , showed that lOAN can be readily obtained in a continuous process consisting of reactive contacting. U.S. Patent No. 3,412,137 for S mountain tb is HMTA
A method for producing IDAN by reacting an aqueous solution of (hexamethylenetetramine) with HCN (hydrogen cyanide) in an aqueous medium buffered to a pH of about 5-6.5 is taught.

Philbrooketal U.S. Patent 3, Iso 6, 19
8 forms an aqueous mixture of HMTA, HCN and a strong acid and passes this mixture (having an acidic pH, e.g. pH 3-5) continuously through a tubular reactor at about 50-1200 C to produce the desired MAN. teaches you how to do it.

U.S. Patent No. 2,895, Team 9, published MA by hydrolyzing IDAN with an alkali metal hydroxide.
It teaches converting N to an alkali metal salt of iminodiacetic acid.

Moreover, Seonon has combined such salts with iminodiacetic acid (m
It also teaches that it can be converted to A). According to the invention,
In the reaction zone, an aqueous solution of hexamethylenetetramine at a temperature of 0 to 80 °C, an aqueous solution of formaldehyde at a temperature of 0 to 80 °C, and HCN at a temperature of 0 to 25 °C were added. The ratio is in the range of 1:1 to 2.2:6.9 to 8.6 and p
continuously feeding the reaction mixture in an amount sufficient to form a reaction mixture in which H is in the range of 5 to 10 and at a rate to establish a residence time of 0.05 to 20 minutes in the reaction zone; is added continuously while maintaining the temperature between 50 and 250 qo, thereby forming a product mixture containing iminodiacetonitrile, withdrawing the product mixture from the reaction zone, and recovering iminodiacetonitrile therefrom. A method for continuously producing iminodiacetonitrile is provided.

In a preferred embodiment of this process, the temperature in one continuous reaction zone is between 120 and 170 qo.

2 The residence time in the continuous reaction zone is between 0.1 and 5 minutes.

3 The pH of the aqueous reaction mixture is 6.5-9.5.

4. The aqueous system withdrawn from the continuous reaction zone, i.e. the product mixture, is cooled to 0-4000 ℃ and the iminodiacetonitrile crystals are separated from it. 5 HMTA:
The molar ratio of formaldehyde:HCN is 1:1.6-2
．． 2:7.2-8.0, more preferably 1:1.8:
It is 7.6.

HMTA and formaldehyde can be fed to the reaction zone as a combined solution formed by mixing an aqueous formaldehyde solution and an aqueous HMTA solution in a mixing and storage zone.

Two mixing and storage zones can be used if desired. In an operation using two mixing and storage zones, an aqueous solution of HMTA and formaldehyde can be prepared in a first mixing and storage zone while simultaneously feeding a pre-prepared aqueous solution from a second mixing and storage zone.

Second mixing and storage zone empty (or nearly empty)
When the H
An aqueous solution of MTA and formaldehyde can be fed therefrom continuously to the reaction zone, while a new lot of said aqueous solution can be prepared in the now empty (or nearly empty) first mixing and storage zone. By feeding from one mixing and storage zone and simultaneously charging (preparing) a new lot of said aqueous solution in the other zone, the continuous supply of aqueous solutions of HMTA and formaldehyde to the reaction zone can be maintained for extended periods of time without interruption. Capable of continuous operation. The concentrations of HMTA and formaldehyde in the aqueous solution of HMTA and formaldehyde are not critical.

However, the solution generally contains about 5-30% HMT.
Contains A. The solution is generally prepared from an aqueous solution containing 30-50% formaldehyde, and the molar ratio of HMTA to formaldehyde in the solution is 1:1-2.
．． Should be 2. In a preferred embodiment of the invention, the reaction zone is provided with (i) a hexamethylenetetramine solution and (ii) an acid-stabilized aqueous mixture of formaldehyde and HCN.

The acid-stabilized aqueous mixture of formaldehyde and HCN is
It can be prepared by mixing HCN with an aqueous solution of stabilizing acid and formaldehyde in a mixing and storage zone.

Two mixing and storage zones can be used if desired. In operations with two mixing and storage zones, the acid-stabilized aqueous mixture can be prepared in the first mixing and storage zone while simultaneously feeding the pre-prepared acid-stabilized mixture from the second mixing and storage zone.

Second mixing and storage zone empty (or nearly empty)
When the first mixing and storage zone is full, the acid-stabilized aqueous mixture of formaldehyde and HCN contained therein can be fed to the continuous reaction zone, while the now empty ( A new lot of the acid-stabilized mixture can be prepared in the first mixing and storage zone (or nearly empty). Continuously feed the acid-stabilized aqueous mixture of formaldehyde and HCN to the reaction zone by feeding from one mixing and storage zone and simultaneously charging (preparing) a new lot of acid-stabilized mixture in the other. Continuous operation can be carried out for long periods of time without interruption. When preparing an acid-stabilized aqueous mixture of formaldehyde and HCN, sufficient acid (e.g.
S04, HC1, 3P04, etc.) is preferably included in the mixture to bring the pH to about 1 or 2.

As long as the pH is about 1 or 2 or somewhat lower or higher (e.g., about 4 or less), and the acid-stabilized aqueous mixture of formaldehyde and HCN is
The bait is not critical as long as it brings the pH of the reaction mixture when mixed with the above mentioned range from 5 to 10. The concentration of the formaldehyde solution used is not critical and is generally about 30 to
It is 50%.

Although the concentrations of both HCN and formaldehyde in the formaldehyde acid-stabilized mixture are not critical, the molar ratio of formaldehyde to CN is about 1-2.2:6.9-
It should be 8.6. Generally, the concentration of formaldehyde in the acid stabilizing mixture is about 5-30%. As mentioned above, Mmer US Pat. No. 2,794,044 teaches a method for making IDA.

This Mmer document correctly states the following. The obvious reaction formula for the reaction that produces iminodiacetonitrile is NH30XH201CN→HN(CH2CN)2
It is 12LO.

However, when the reactants are mixed in the stoichiometric amounts required by this reaction equation, the product cannot be isolated even by adjusting the pH. The following different reaction equation gives the best yield, about 65%
represents the stoichiometric ratio required to obtain Toko Yamabi 20 Jusei CN [Part 3 Mushikawa (CQCN) 20 NH 30 Mother LO NH3 and CH20 produce HMTA at this ratio, so when NH3 is produced, it is necessary to neutralize it.
Using S04, the equivalent reaction equation would be:

(C ratio) 6N4 ten fine CN + 1' phantom LS04 one phantom melon (CH
2CN)21/2(NH4)204This reaction scheme shows some drawbacks of the above IDAN production method. Only 3/4 of the N in HMTA will change to IDAN, the remaining 1/4 will be NH3 (i.e. (NH4)2S04)
released as. As a result, HMTA is not used efficiently. Liberation of the N ratio requires constant control of speckles by the addition of QS04. The product is therefore a slurry of IDAN crystals in a liquid containing dissolved IDAN, HCN, other organic by-products and a large amount (N ratio) of 2S04. In practice, this liquid cannot be recirculated and must be disposed of after expensive effluent treatment. According to the present invention, from HMTA, formaldehyde and HCN, the following reaction equation, (CQ)
It was found that IDAN can be manufactured according to 6N4 10th CN 10th CHO → (HMTA) 4HN (CQCN) 21st 20th (MAN).

Such a method can avoid the aforementioned problems. Since NH3 is not liberated, all HMTA will be available for conversion to MAN and ratio S04 is unnecessary. Therefore, higher yields can be obtained, precise pH control is not required, and the formation of intermediate glycolonitrile is avoided. Therefore, this method can easily be made continuous. Furthermore, since the product is essentially MAN and not contaminated with inorganic materials, the entire reaction mixture can be hydrolyzed with alkali metal hydroxide to mA
It can be M2. Once this is done, the problem of effluent is completely eliminated. If MAN is the desired product, it can be crystallized from the reaction product. The resulting liquid is (
Since it does not contain 2S04 (N ratio), it can be hydrolyzed with NaOH to obtain useful MANa2 without producing the undesirable by-product sodium sulfate. M
When AN is hydrolyzed to IDANa2 (or IDAK2), the ammonia produced can be recovered and used as fertilizer (e.g. as ammonium sulfate or ammonium phosphate).
Alternatively, recovered ammonia can be used for HMT
A and/or HCN and recycled to the process.

Other uses of the recovered ammonia will be obvious to those skilled in the art. Conveniently, the continuous reaction zone used in the process of the invention is surrounded by a heat exchange medium (eg, oil, dowsum, chlorinated hydrocarbon, steam, etc.) at a constant temperature and heated or cooled as required.

Alternatively, when heating is required, using electrical heating,
The temperature within the reaction zone can be maintained constant. Additionally, other methods of temperature control will be obvious to those skilled in the art. The IDAN product is a solid and is extracted from the cooled aqueous mixture (aqueous system) leaving the tubular reactor by centrifugation,
It can be separated by decantation or filtration.

Alternatively, the aqueous system leaving the tubular reaction zone can be fed to a solution of alkali metal hydroxide and directly hydrolyzed to the alkali metal iminodiacetate (IDAM2).

When operating at temperatures in a continuous reactor of about 10,000 or higher, pressures in excess of atmospheric pressure (760 Torr) are maintained in the aqueous system in the reaction zone to avoid excessive evaporation within the reactor.

Water versus reaction components (HMTA, formaldehyde and HC
The weight ratio of N) can vary within wide limits.

Very good results are obtained when the weight ratio of water to reactants is 10:1 or higher, and the mixing zone (
Very good results can be obtained if an amount of water is used that keeps the solution (one-phase) just in the T-shaped or cross-shaped and continuous reaction zones. In the process of the invention, the continuous reaction zone can be a tubular reactor, a continuous outflow autoclave, etc. When using a tubular reactor, the Namiai cross section and/or
Alternatively, one or more combined T-shaped sections (depending on the number of feed streams feeding the reactor) can consist of an inlet and a mixing zone that are part of the reactor, and the feed streams are part of the reactor. Mixing can be carried out in such a mixing cross-shaped section and a mixing T-shaped section.

When using a continuous outflow autoclave,
The reactant feed streams may be fed to the autoclave and mixed therein by mixing means provided within the autoclave.

Alternatively, a mixing cross and/or one or more mixing sections may be attached to an autoclave to form an inlet to the autoclave, and such mixing cross and/or forming a portion of the reactor may Alternatively, the feed streams can be mixed in a mixing tee. When using a mixed cross section and at least one mixed T section, or when using two or more mixed T sections, connect the cross section and the T section or two or more T sections in series. so that the discharge from one discharge arm constitutes the supply to the other feed receiving arm.

The concentration of the solution used to form the aqueous reaction mixture in the process of the invention is not critical. however,
It is generally preferred to use an aqueous solution of formaldehyde containing about 30-50% HCHO and an aqueous solution of HMTA containing about 10-30% HMTA. The HCM can be supplied as an aqueous solution of HCN containing about 20-99% HCN, as a vapor of HCN, or preferably as anhydrous liquid HCN. The invention will be further understood by reference to the following examples and methods.

The example was an actual experiment. Although the method was not actually carried out, it further illustrates the production of MAN according to certain embodiments of the method of the present invention. Example 1 An aqueous solution of HMTA and formaldehyde containing 14.2% HMTA and a molar ratio of HMTA to formaldehyde of 1:1.95 was prepared.

This solution and HCN were simultaneously fed by separate metering pumps to the mixing section at the head (inlet) of a continuous tubular reactor. The molar ratio of HMTA to Japan CN is 1:7.7
It was 8. 1 piece of 1/8 inch (0.32 skin) x 10 foot (304.8 cm) jacketed steel pipe
0 area and the following 1/8 inch (0.32 skin) x 2
Three sections of 0 foot (609.6 c) non-jacketed steel pipe were connected in series to form a continuous reactor.

A thermocouple and sampling valve were installed at the end of each zone. The temperature of the mixture in the reactor was adjusted to 40 psig (2
．． 14 by passing water vapor of 8k9/Ken Yu)
Controlled to 000. A pressure relief valve allows the pressure in the continuous reactor to be adjusted to 200-250 psig (14.
The weight was controlled at 1 to 17.6 kg/day). Weighed samples of the nitrile product were collected at various sampling valves and saponified with sodium hydroxide solution.

The saponified sample was analyzed by silylation gas chromatography to detect glycine, IDA and nitrilotriacetic acid (NTA).
was analyzed. In addition, the saponified sample was prepared using standard copper chloride (0
) was titrated. The results obtained are listed in Table 1 below. Example 2 The general procedure of Example 1 was repeated, but using other temperatures, residence times and molar ratios.

In this case, samples were taken only at the first sampling point at which the reaction was completed (ie, at the maximum residence time at which the reaction was completed). The results obtained are shown in Table 0' below. Example
3 The general method of Example 2 was repeated, but in this case HMT
The aqueous solution of A and formaldehyde was heated before being fed to a continuous reactor (continuous reaction zone) in which it (aqueous solution of HMTA and formaldehyde) was mixed with HCN.

In this example, the first two zones of the continuous reactor were not heated, but the next eight zones were supplied with steam as in Example 1. The results obtained are listed below. Saunde et al. (U.S. Patent No. 3,167, Group 0
) reported that when formaldehyde, HCN and ammonia are reacted to produce MAN, a product mixture of IDAN and glycinonitrile is obtained.

Their products sometimes contain small amounts of N-methyleneglycinonitrile. In the present invention, it has been found that a small amount of NTAN (nitrilotriacetonitrile) is produced as a creation product when MAN is produced by the method of the present invention. It has also been found that the ratio of glycinonitrile to IDAN in the reaction product exiting the reaction zone of the present invention can be increased by adjusting the molar ratios of the reaction components (HMTA, formaldehyde and HCN) (see Table D).

This technique is particularly useful when both IDA and glycine are desired. This is because glyconitrile rich in IDAN can be produced and converted to the ratio NCH2COONa and IDANa2, which can then be converted to glycine and mA. Glycine and IDA can be separated from the aqueous solution by crystallization and recovered separately. In this way (see Table 0, Experiment No. 8), a product yielding about 14% glycine (as an upper limit) and about 84% IDA (as a lower limit) is obtained by converting the reaction components into molar ratios of HMTA to Nihon CHO to Nihon CN. 1:1:
The product leaving the continuous reaction zone, which is obtained by feeding at 6.95° C., while being considerably richer in glycinonitrile and considerably lower in 1OAM, has a molar ratio of said reaction products of 1:0 to 1:6. 82 and 1:0:5.
98 (Experiment No. in Table 0).
．． 9 and no. 10).

Molar ratio of HMTA:HCHO:HCN approximately 1:0:5.4
This further increases the ratio of glycinonitrile to IDAN in the product exiting the continuous reaction zone. Q To＜ Shinpaku.

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2.2:6.9-8.6 or 1:1.6-2.2:7
．． 2-8.0, the process of Example 1 can be carried out by separately metering the aqueous solution of HMTA, the aqueous solution of formaldehyde, and HCN to a continuous reaction zone (continuous reactor).

Such a method uses approximately 85% of the HCN' supplied.
It will produce MAN at ~90% conversion. Method
2 An aqueous solution of formaldehyde, HCN and an amount of acid (
For example, first formaldehyde and HC
The method of Example 1 can be carried out by preparing an acid-stabilized aqueous mixture (solution) of N.

This solution generally has a pH of about 1-4 or 1-2 or 2.
It would be ~3 or 3-4. The molar ratio of formaldehyde to CN in such solutions is about 1-2.2:6.9-
Should be 8.6 or 1.6-2.2:7.2-8.0. This solution and the aqueous HMTA solution were metered separately into a continuous reactor to maintain a molar ratio of HMTA to formaldehyde to CN from 1:1 to 2.2:6.9 to 8.6 or from 1:1.6 to 2.2; can be 7.2 to 8.0.

MAN has a theoretical yield of about 85 to
It will be produced in 90% yield. MAN is an intermediate on the way to IDA, and this mA is an ESChWeile
(Ann-1894 '278, 229-239).

mA is used for metal plating ratings. German patent number 1
, No. 034,946 (Chem. Abstractsl.
960, 54, 16237e) is a cyanide-bearing copper (
and copper alloys) teaches the use of mA for plating. When mA is present in such a case, copper (or steel alloy) is plated (precipitated) as a bright coating. The use of IDA to preserve rubber latex is covered by British Patent 80.
0,089 (Chem. Abstracts l959
, 5, 2672).

When heated in an aqueous medium with approximately stoichiometric amounts of sodium hydroxide solution, IDAN has the following reaction equation HN (C ratio C
N) 212 days 2012 HaOH=(MAN)HN(CQ
COONa) 20 yields iminoniacetate nitrium (IDANa2) according to day 3 (mA of sodium salt, ie IDANa2).

French Patent No. 1,190,714 (Chem. Abs
tractsl96 5 also 25993) removes residual catalysts (e.g. Ti, Cr, Fe, V
or salts of AI).

Claims (1)

[Claims] 1. In a reaction zone, an aqueous solution of hexamethylenetetramine at a temperature of 0 to 80°C, an aqueous solution of formaldehyde at a temperature of 0 to 80°C, and HCN at a temperature of 0 to 25°C, hexamethylenetetramine:formaldehyde. :HCN molar ratio is in the range of 1:1 to 2.2:6.9 to 8.6 and p
continuously feeding the reaction mixture in an amount sufficient to form a reaction mixture in which H is in the range of 5 to 10 and at a rate to establish a residence time of 0.05 to 20 minutes in the reaction zone; is added continuously while maintaining the temperature between 50 and 250°C, thereby forming a product mixture containing iminodiacetonitrile, withdrawing the product mixture from the reaction zone, and recovering the iminodiacetonitrile therefrom. Continuous production method for iminodiacetonitrile. 2. At least one of the reaction components is supplied to the reaction zone as part of a mixture that also contains a stabilizing acid to bring the pH of the reaction mixture to between 5 and 10. the method of.