DE2355059C3 - Process for the recovery of alkali or ammonium effluents - Google Patents

Description

will also have acidic alkali citral solutions prepared 25. This is especially important when out of the

Alkali citrate solutions by means of electrodialysis Lemon

The invention relates to a method for the acid to be obtained. For this purpose, Tn is obtained of alkali or ammonium citrates from sodium citrate solutions because of their relatively high Lemon pH value obtained chemically or fermentatively is less suitable.

acid solutions by means of extraction. 30 Suitable amines according to the invention are both

For obtaining alkali citrates from fermen- for example N-lauryl-N-trialkylmethylamine, N-Mei'ition solutions Several processes have already been described, e.g. yl-di-n-octylamine, tri-isononylamine or tri-n been. So it is known, the citron decylaniin.

acid first from the fermentation solution by means of organic solvents are

To precipitate milk of lime and then use it accordingly, which can be reacted with calcium citrate and alkali carbonate which cannot be mixed with water and which have a good absorption capacity for the zcn. After removing the calcium carbonate system that has formed, have aniine-citric acid. A trisodium citrate solution is obtained as the solution. Hydrocarbons, alcohols, esters, alkali citrates can also be used by direct neutroketones or mixtures thereof, and citric acid solutions can be prepared. For example, cyclohexene, carbon tetrachloride, ^L.

however, it is necessary that the lemon methyl isobutyl octone, 2-pentanone, 2-octanone, 5-mesic acid solution already exists in pure form. Both ethyl-3-heptanop, 2,6-dimethyl-heptanone, methyliso- \

Methods are cumbersome and many rely on- bulylcaibinol, 2-methyl-5-hexanol, 1-octanol, agile process steps ahead. 2-ethyl-1-hexanol, carbolxylene, cyclohexyl acetate ^

It is also known. Citric acid using Ex-45 or tri-n-butyl phosphate.

traction agent from their aqueous solutions too important for the phase separation process and the ^c .

win. According to the French extraction equilibrium, the extraction agent used is the volume ratio ν '

French patent specification 1211 066 secondary butanol of amine to solvent as well as the molar ratio and according to German Auslegcschrift 1,268,088 nis m of amine to citric acid. With the increase of

Tri-n-butyl phosphate, the latter in a mixture with a Koh- 50 v value increases the extraction yield, verenwasserstoffen, Ethers, esters or ketones, however, take longer to separate the phases. !

tries. With these known working methods, the optimal volume ratio of amine to

However, no satisfactory results obtained organic solvent is in the range of, since the partition coefficients in the 0.05 to 2.0, preferably 0.3 to 0.7, and the MoI-both extraction process is so low (around 1.0) _{The 5S} ratio of amine to citric acid should be 0.5 to 10, that is, large amounts of extractant and preferably 1.5 to 3.5. ^c

many extraction stages are required. When extracting citric acid from a

It has now been found that these disadvantages are not about 8 "/ o fermentation solution with tri-isononyl- '

occur when using amine as extraction agent with methyl isobutyl ketone as solvent

A water-immiscible mixture of an amine 60 is advantageously used, for example, with a

the general formula volume ratio of tri-isononylamine to methyl- ^

isohutyl ketone of 1: 1.5, which has a v value of 0.66

corresponds to and a molar ratio of amine to

R ₁ citric acid of 2: 1, that corresponds to one

65 m value of 2nd N - R, the following table shows the relationship _f '

the partition coefficient of the v and m values. R- The extraction of citric acid from the ferment

Dependence of the distribution coefficient on the v and / n value

Vol / Vül

Mol.MuI

Citric acid concentration in the
aqueous phase
(Raffinate) in ° / o

Distribution coefficient

1: 1.5 = 0.66

1: 4.0 = 0.25

J: 0.75 = 1.33 J 0.5 ^ = 1.82 1 0.38 = 2.65 1. 0.19 = 5.26

1 ■ 1.10 = 0.91 1 0.73 = 1.37 1 0.37 = 2.70

tation solution was carried out at 20 ° C, as an amine Tri-isononylamine and, as a solvent, methyl isobuiyl ketone used.

The table shows that each. The larger the v- and or m-VVert is, the higher is the distribution coefficient or the lower is the number of extraction stages.

The extraction as well as the Rückexiral-tion can discontinuously or continuously \ <ic z. B. with With the help of a mixer-separator battery or an extraction column.

To obtain the alkali and ammonium citrates, the organic extract is then treated with alkalis, ammonia or its salts such as carbonates, chlorides or sulfates. The equivalent ratio of alkali or ammonium to citric acid is important for optimal implementation of this back-extraction process. Erih-making according to the equivalent ratio of RücKexlraktionsmittel to citric acid in the organic extract 0.1 to 1.2, preferably 0.4 to 0, ^L) 5 amount.

When using, for example, a sodium carbonate solution as a back-extraction means, in Fig. 1 the dependence of the distribution "efficient, the free citric acid and the pl · value of the aqueous back extraction solution plotted from the a value. It can be seen from this that with Use of sodium carbonate by varying the «value. Solutions of disodium and trisodium citrate can be produced. Acid citrate solutions can be obtained by extracting citric acid from the organic extract except by means of sodium carbonate and other alkali and ammonium carbonates or bicarbonates aii.-h with alkaline solutions or ammonia with high partition coefficients to win.

It is advisable to work with inö; lets you concentrate Solutions of alkalis, ammonia or their salts.

When back-extraction with alkali carbonates or bicarbonates lead to temperatures above 20 ° C a shortening of the extraction time and higher distribution coefficients. The return traction will therefore preferably carried out at 30 to 40 ° C with these salts.

The obtained according to the invention! Alkali citrate or ammonium citrate solutions can be concentrated in the usual way to obtain the solid salts will. The solid salts are now widely used as a substitute for phosphates in detergents.

In the following examples, the inventive Extraction process explained

3.02
1.68
0.97
0.42 3.33
4.70
6.02
7.41 3.88
1.75
0.61 1.47
2.75
4.54 example 1

A fermentation solution with 7 ') g citric acid per 1 solution was subjected to a continuous countercurrent extraction according to the mixer-separator principle. The procedure is in the A b b. 2 shown schcmatically (3-stage extraction; 2-stage back extraction). In the mixer 1, 12 liters of the organic phase E ₀ , which contains 4.8 liters of tri-isononylamine and 7.2 liters of methyl isobutyl ketone, and 121 of the aqueous phase A _{1 are} mixed every hour and conveyed to the separator 2, from which 12 1 of an approximately 0.3% aqueous solution (raffinate) run off.

The organic phase E ₁ withdrawn from the separator 2 is added together with 12 1 _; h of the aqueous phase A _{1 is} mixed in the mixer 3 and fed into the separator 4, from which 12 l of the aqueous phase / I ₂ and 121 of the organic phase are removed per hour. The organic phase E. is mixed together with the fermentation solution A ₁₁ , which contains 79 g citric acid per 1 solution, at a rate of 12 l / h in the mixer 5 and then fed to the separator 6. Every hour, 12 liters of the organic extract E ₃ , which contains 76.2 g of citric acid per liter of extract, are withdrawn from the separator 6 and mixed with 6 liters of the aqueous phase W ₁ in the mixer 7 for re-extraction and then fed into the separator 8 . From this, 6 liters of the citrate solution W. “ which contains 152.4 g of citric acid per 1 solution or, calculated as trisodium citrate dihydrate, 233.4 g per 1 solution and 12 liters of the organic phase E _A flow off per hour. 6 liters of the aqueous phase ^ ₀ , which contains 114 g of sodium carbonate per liter of solution, and 121 of the organic phase E ₄ enter the mixer g every hour. The resulting mixture is in

fed into the separator 10, from which 121 of the organic phase E ₀ and 6 1 of the aqueous phase W are withdrawn every hour.

The citrate solution according to the invention diluted to 2% has an extinction of 0.6 (measured at a wavelength of 436 nm; Meßküvcttc: 1 cm; pH - 5.5).

In contrast to this, an O.2% initial fermentation solution adjusted to pH 5.5 with sodium hydroxide solution had an extinction of 0.5 (gt-

measure at a wavelength of 436 nm; Measuring cells: 1 cm; pH = 5.5).

According to the invention, a purity of the citrate solution of 88% was thus achieved.

Example 2

A fermentation solution with 71.5 g of citric acid per liter of solution was subjected to a continuous countercurrent extraction in the device described in Example 1. A mixture of tri-n-dccylamine and methylisobulylcarbinol with a volume ratio of V- 0.644 was used as the extractant.

In the extraction, the organic and the aqueous phases were extracted at the same rate of 12 liters per hour fed to the mixers and separators.

^{An approximately 0.3 n} / o aqueous phase (raffinate) drained from the separator 2, while the organic extract with a content of 68.3 g citric acid per liter of solution was drawn off from the separator 6 and fed into the mixer 7.

During the back extraction, the organic phases were 12 1, the aqueous phases were 4 1 per Hour fed into the mixers and separators or withdrawn from the mixers and the separators. The mixers 7 and 9 were kept at a temperature of 38.degree.

A potassium hydroxide solution, containing 162 g of potassium hydroxide per 1 solution was used. The obtained aqueous Extract which ran out of the separator 8 contained 204.9 g citric acid per 1 solution or

ίο calculated as trisodium citrate dihydrate 313.8 g per 1 Solution.

The citrate solution diluted to 2% has a Extinction of 0.72 (measured at a wavelength of 436 nm; Meßküvcttc: 1 cm; pH = - 6.3).

The extinction of the initial fermentation solution adjusted to pH 6.3 with potassium hydroxide and diluted to 0.2% on the other hand, was 0.55 under the same measurement conditions.

A citrate solution purity of 87% was thus achieved.

For this purpose 2 sheets of drawings

Claims (1)

1 2 wherein R ₁ and R., hydrocarbon radicals with 7 to Claim: 15 carbon atoms and R ₃ hydrogen or one Hydrocarbon residue with 1 to 15 carbon process for the production of alkali or atoms means, and an organic solution ammonium citrate used from chemical or fcrmcnta- 5 agents. tively obtained citric acid solutions with- Surprisingly, it was found that the te! s extraction, characterized thereby- method according to the invention as extraction agent net that one is used as an extraction agent with a mixture with a high selectivity against water Immiscible mixture of one above the impurities shows and higher vertei-amine of the general formula 10 lungskocffizicnten in the extraction of the lemons acid from their aqueous solutions than the R _{1 used} in the known methods of extraction \ tion agent, so that a very good extraction effect N - R, is achieved. According to the invention after return 15 Extraction from the organic extract Alkali-R, citrate with good yield and of high purity receive. _t wherein R, and R., hydrocarbon radicals with 7 The inventive method offers above η up to 15 carbon atoms and R ₃ hydrogen have the advantage that not only trisodium, or a hydrocarbon _{radical with 1 to 2} o citrate - as in the known conversion of 15 carbon atoms, and an organic calcium citrate with alkali metal carbonates - are obtained ^ niche solvents used. den can, but that depending on the amount of ^ Alkali salt, which is used in the back extraction,