FR2505822A1 - PROCESS FOR THE PRODUCTION OF FUMARIC ACID FROM EXHAUST GAS WASTE WATER RESULTING FROM OXIDATION OF HYDROCARBONS - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR PRODUCING FUMARIC ACID FROM EXHAUST GAS WASHING WATERS RESULTING FROM OXIDIZATION OF HYDROCARBONS. THIS PROCESS INCLUDES A PRIOR THERMAL TREATMENT OF THE MALEIC ACID SOLUTION, OBTAINED IN ANY IMPURE MANNER, WITH TRANSFORMATION OF A PART OF THE IMPURITIES, SO AS TO PREVENT THEIR PRESENCE IN THE FINISHED PRODUCT, WITH POSSIBLE SIMULTANEOUS CONCENTRATION, AND THEN POSSIBLE FILTRATION. AT HOT, ISOMERIZATION IN FUMARIC ACID, CRYSTALLIZATION ACCORDING TO A PREDETERMINED TIME-TEMPERATURE DIAGRAM, SEPARATION OF MOTHERWATER BY FILTRATION, THEN DISSOLUTION IN WATER OR IN A FUMARIC ACID SOLUTION, DECOLORATION, RECRISTALLIZATION AND DRYING. THE PRODUCT OBTAINED IS OF A SPECIAL PURITY ALLOWING ITS USE ESPECIALLY IN PHARMACEUTICAL PRODUCTS AND FOOD PRODUCTS.

Description

The present invention relates to a process for the production

  industrial fumaric acid from wash water from oxidation

  hydrocarbons, with high yields and the characteristics

  special characteristics of the purity of the product obtained, mainly because of a pretreatment in combination with a subsequent isomerisation of a specially pure product.

  more commonly used for the production of fumed acid

  isomerization, using known catalysts, such as, for example, thiourea, mercaptan or similar catalysts,

  maleic acid fumaric acid, with subsequent crystallisation

  of the acid obtained, separation of the precipitate,

  elution of the precipitate itself in hot water, decolourising

  solution using bleaches such as

  that, in particular, coal, hot filtration, crys-

  cooling isation, separation of the precipitate

  of fumaric acid and subsequent drying.

  Due to the extreme variety of starting materials, operating conditions and catalyst activities, impurities are present in the initial solution, such as, for example, quinones, and especially naphthaquinone, benzoic acid, toluic acids and the like. , citraconic acids, phthalide, phthalic acid,

  other aliphatic and aromatic acids and aldehyde

  hydes, condensed products, polymerized products and

  inorganic acids and salts.

  are not capable of totally and completely eliminating all the impurities mentioned above which, consequently, remain present in the final product and prevent its subsequent use in chemistry in a general way and in pharmaceutical products and products In particular, it should be noted that, if fumaric acid is pure, it can be used in accordance with the regulations of various countries which are extremely stringent on these materials to replace

  citric acid, tartaric acid and / or ascorbic acid

  It is clear and obvious that the presence of impurities as specified above in the final product severely limits the areas and

means of industrial use.

  In order to overcome these difficulties, the present invention provides a new industrial process for producing fumaric acid from industrial plant exhaust washwater from facilities.

  which oxidize hydrocarbons in general, as in parti-

  include ortho-xylene, naphthalene, their mixtures, alkyl naphthalenes, benzol, benzol-like substances, butane, butylene, etc., or mixtures thereof, or from mixtures of washings from any type of plant oxidizing the hydrocarbons indicated above, with the possibility of obtaining a purer product and having better chemical and physical characteristics than the

  product obtainable according to the prior art.

  In particular, the solution of maleic acid, regardless of how it is obtained and at any concentration, is purified and treated by isomerization to

  fumaric acid of the resulting maleic acid

  obtained in this way is separated by crystalli-

  and then is purified and dried.

  The present invention can be better understood from

  the following detailed description, given only as a

  non-limiting example relating to an embodiment possible for obtaining fumaric acid according to the invention. More precisely Figure 1 is a block diagram illustrating the

  production of fumaric acid according to the invention.

  Figure 2 shows time / temperature plots of deposition and cooling and pre-treatment.

  then performed respectively according to the invention.

  Figure 3 shows the time / temperature diagrams of the isomerization phase and the filtration phase.

filter wash, respectively.

  Figure 4 shows the time / temperature diagrams of the dissolution / fading and phase phases

  crystallization / centrifugation, respectively.

  To better understand the purpose of the in-

  vention, we give below as a general indication

  a possible composition of the starting materials.

Example 1

  The average indicative composition of the exhaust gases resulting from the oxidation of a mixture is given below.

  ortho-xylene (30%) and naphthalene (70%), after separation

ration of phthalic anhydride.

  Indicative composition of the exhaust gas Phthalic anhydride 0.5 g / N m 3 Maleic anhydride 2.0 g / N m 3 Sulfuric acid 0.27 g / N m 3 1, 4 naphthaquinone 0.1 g / N m 3 Benzoic acid 0.05 g / N m 3 Other by-products 0.01 g / N m 3 Total 2.93 g / N m

Example 2

  Guideline levels of a maleic acid solution Maleic acid 25% by weight Naphthaquinone 0.65% by weight Phthalic acid 2.5% by weight Other organic acids 0.7% by weight Sulfuric acid 0.2% by weight Essentially, the process according to the present invention consists of the following phases:

PHASE 1

  Prior heat treatment of the maleic acid solution, however obtained, and impure, specifically of the type indicated in Example 2, with the presence of the indicated impurities This treatment consists in heating the solution to a temperature of more than 900 C following a curve such as that shown on

the diagram of Figure 2.

  This operation may coincide with a concentration of the solution, if this concentration is necessary. Pre-treatment produces a transformation of part of the impurities so as to prevent them from being present in the final product. Bleaching coal or other substances acting similarly can be

  added even during these pre-treatment phases.

PHASE 2

  Hot filtration through a suitable filter, under pressure, vacuum, flat, rotary, continuous or interrupted,

  with or without washing and with or without air drying.

PHASE 3

  The maleic acid contained in the solution which has been filtered can then be isomerized, using thiourea as a catalyst, into fumaric acid, which is crystallized by cooling. This phase is clearly indicated on the block diagram of FIG. , and can

  be conducted according to the diagram in Figure 3.

  The entire operation of isomerization and crystallization

  The process is carried out according to a specific time / temperature diagram so that maximum yields (92%) are obtained and to produce crystals of such size and size that they encompass the smallest possible amounts of impurities and that they are suitable for the subsequent operations of

  treatment (see attached photograph).

-5-

  It should be noted that if we operate in

  different finishes, the finished product will be of quality

  lower and the cost of production will be higher.

  It should also be noted that the diagram presented should be considered as an optimal diagram for industrial production, because even higher yields than indicated here could be obtained by increasing the duration of the isomerization, even if the slowness

  reaction makes it inconvenient.

PHASE 4

  The fumaric acid crystals are separated from the mother liquors by filtration, using a suitable flat filter or

  rotary, continuous or interrupted This filtration, accom-

  Suitable scrubbing treatments using 250 C saturated solutions of pure fumaric acid and drying techniques by air or other gases may be made using FRP rotary filter pressure units manufactured by COGEIM. or flat self-discharge pressure filters manufactured by Seitz and Funda, with basket-type or continuous centrifuges with panel wash In particular, it is possible to

  conduct the operation using the device called filter-

  pressfiltro press manufactured by Comber.

  Time / temperature diagrams are very important

  also in this phase, and in particular those

  on the right side of Figure 3 for filtration and suspension washing using the

"pressofiltro" from Comber.

  As shown in the diagram of Figure 1, the waters

  mothers resulting from this operation must be destroyed in an incinerator or biologically purified

  in an activated sludge treatment plant.

PHASE 5

  The crude fumaric acid in crystals is dissolved in water or in a saturated solution of fumaric acid at 250 [deg.] C., that is to say in the mother liquors coming from the

  second crystallization This phase is clearly indicated

  Figure 1 optimizes this operation by appropriately adjusting the temperature, which must be between 95 and 98 WC / min, and, if necessary, by adjusting the pressure of

  in order to raise the temperature and increase

  the solubility of fumaric acid.

PHASE 6

  Bleaching charcoal is added to the above solution, maintained at a temperature of between 95 and 98 ° C when operating at ambient pressure. This charcoal may be that under the trade names Anticromos 00, Carboraffin C, Darco S 51 The mixture is stirred and filtered hot in the "presso-filtro" This phase is clearly

  indicated in the left part of figure -4.

PHASE 7

  The cooling of the filtered product makes crystallize

  fumaric acid This is separated by a centrifugation

  semi-automatic type, having a horizontal axis and an automatic discharge The use of this type of centrifuge will leave about 5 to 7%

residual moisture.

PHASE 8

  A fluid-bed hot-air drying apparatus can be used for drying. Obviously, any device that removes moisture and any traces of impurities that can be removed by

  air currents or water vapor, such as benzoic acid.

  In particular, the method can use the drying apparatus called T S, manufactured by the firm S I E Soc.

Ital Essicatoi of Caleppio (MI).

Example 3

  The fumaric acid obtained using the industrial process described above has the following characteristics: Fumaric acid: 99.7% Color (5% in alcohol) 0-10 Hazen Moisture 0.2% Ash 0.01 % Iron 2 ppm

Example 4

  In addition, general indications concerning the yields are given below: Isomerization yield: 92% of the maleic acid present in the initial solution Efficiency of the purification: 94% of the crude fumaric acid Total yield: 86.5% of maleic acid It is obvious that the invention is not limited to the embodiments described and that any variations can be made, in particular with regard to

  time, quantities, temperatures and catalysts.

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Claims (6)

  Process for the production of fumaric acid from the exhaust gas washing water resulting from the oxidation of hydrocarbons, characterized in that a preliminary heat treatment of the maleic acid solution is carried out, however it is obtained, and impure, with transformation of a part of the impurities so as to eliminate their presence in   the final product, and then hot filtration, isomeri-   in fumaric acid, crystallization in accordance with a predetermined time / temperature diagram, separation of the mother liquors by filtration, subsequent dissolution in water or in a fumaric acid solution, decolourisation, recrystallization and drying.   2 Process according to claim 1, characterized in that it combines the isomerization phase with the prior heat treatment phase of the solution of maleic acid.   3. Method according to one of claims 1 and 2,   characterized by the fact that the heat treatment   lable specified is to heat the solution to a temperature between 70 and 1000 C and preferably above 90 'C.   4 Process for producing fumaric acid according to one   of the preceding claims, characterized in that   that it combines the preliminary heat treatment phase with a possible phase of simultaneous concentration of maleic acid solution (obtained in any way and impure).   Method according to one of the preceding claims,   characterized by the fact that is carried out according to   a time / temperature diagram for the isomeric phase   which comprises a heating step, so that the product mass is exponentially increased from 30 to 100 ° C over a period of about four hours, followed by a holding phase at that time. temperature for approximately four hours, and   a subsequent phase of cooling and crystal-   in which the temperature falls, in about three hours, to 50 C, this procedure giving a   optimal yield, between 85 and 95%.   Process according to Claim 5, characterized in that, by operating according to the specified time / temperature diagram, crystals of such sizes and sizes are obtained as to include the smallest possible quantity of impurities and are thus suitable for the   subsequent processing operations -   7 Fumaric acid of special purity, in a crystalline form, obtained by the process of any one   of the preceding claims, as a product industrial new.