Catalyst to obtain 2,3:4,6-diisopropylidene-l - carbofuran and the method of its preparation

 

(57) Abstract:

Proposed to be used to obtain 2,3:4,6-di-isopropylidene - a-L-carbofuran (an intermediate in the synthesis of vitamin C) performanceby catalysts with molar ratio of Mo : P = 3 - 12. The catalysts synthesized by dissolving in water or a solution of phosphoric acid phase composition of P2O5xMoO3(x = 6 - 24) or MoO3preliminarily subjected to mechanochemically activation at 20 - 100oC and the concentration of the parent compounds 5 to 50% wt. The application of these catalysts allows to increase the yield up to 90% and to solve the problem of regeneration of the catalysts. 2 S. and 1 C.p. f-crystals.

The invention relates to the chemistry of heterocyclic compounds, in particular to the improvement of catalysts obtain 2,3:4,6-diisopropylidene- -L-carbofuran (diazocarbonyl, DAS) formula

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used in the medical industry as an intermediate in the synthesis of vitamin C.

Currently, DAS produced by the reaction of L-sorbose and acetone in the presence of oleum, as catalyst [1] the Catalyst is neutralized at the end of each cycle of the reaction. Exit DAS 75 80% the Main drawback of this process large quantities of waste (mainly Na4SiW12O40nH2O, H3PW12O40nH2O, H5BW12O40nH2O, H4GeW12O40nH2O (n 13 30), in the amount of 0.015 0.02 kg 1 kg sorbose. The output of the DAS up to 80% the Use of the CCP eliminates waste Na2SO4and the resulting salt of the CCP after appropriate processing can be returned to the process [2, prototype] However, the method of "appropriate treatment" is not specified. Analysis of the known data on the chemistry of the CCP showed that organic methods of regeneration W-CCP no, and known methods (for example, ether extraction of the aqueous solution in the presence of HCl or H2SO4[3] ) are accompanied by a loss of 20 to 30% W, the use of extraneous reagents and such a large amount of wastewater that the advantages of using W-CCP for the synthesis of DAS is lost. To use CPC only 1 time, without regeneration, also not economically feasible. In addition, when using W-HPC exit DAS is not big enough.

The invention solves the problem of the development of more active catalysts for the synthesis DAS on the basis of the CCP and the method of their preparation.

The tasks are solved by the application for the synthesis of DAS cat who Finance showed what CCP H3PMo12O40H7PMo11O39H3PMo9O31H6P2Mo5O23more active in the synthesis of DAS than W-CCP. And their activity increases with increasing ratio Mo P. However, the synthesis of these CCP individual species complex and the stability of small solutions they are in equilibrium with each other. Mixtures of these CCP also exhibit high catalytic activity, which allows to use them successfully for the synthesis of DAS. Practically useful catalysts with a total molar ratio of Mo P 3 12. The upper limit of this ratio corresponds to the limit of solubility MoO3in solutions of H3PO4. At the Mo:P<3 are not quite active catalysts.

The known method of synthesis mixtures phosphomolybdenum CCP with a total molar ratio of Mo: P= 1 to 10 by interaction MoO3and aqueous solution of H3PO4at 100 140oC and a pressure of 0 to 5 MPa for 6 to 24 h [4, prototype] the Disadvantages of the method: the duration of the synthesis, large energy consumption, the necessity of using hydrothermal conditions, inability to obtain catalysts with high ratios of Mo P (for examples, Mo:P7,7).

These are not enohimicheskaja activation. The parent compounds are molybdenum oxide MoO3or phase composition of P2O5xMoO3(x 6 24) obtained after thermal treatment of spent catalysts synthesis DAS. The parent compound is subjected to mechanochemical activation in any apparatus suitable for this purpose. Activated MoO3dissolved in the solution of H3PO4when the molar ratio of Mo:P=3 12. Activated phase composition of P2O5xMoO3dissolve in water. Dissolution produced under stirring at a temperature of 20 100oC and the concentration in the water source connection 5 to 50 wt. The time for complete dissolution of 1 to 30 minutes Reduce the temperature of the dissolution causes a sharp increase in time of the synthesis catalyst. The increase in the concentration of the parent compounds in excess of 50% leads to partial dissolution. After dissolution, the solution was evaporated to dryness and get the dry catalyst. The output of the catalyst 100% for Mo in all cases.

In a similar way (at the Mo:P=9), but with a specific shutter speed, you can get individual GPK H6P2Mo18O62[5] which, however, little activity and synthesis of DAS is not used.

The application of mechanochemical activation of the source connection of the p the I the usefulness of the proposed catalysts and their method of synthesis consists in the following:

1) the increase in the output of the DAS to 90%

2) reducing the cost of the catalysts (Mo cheaper than W);

3) ecological purity of the method of synthesis (no waste, low energy consumption);

4) the possibility of regeneration and reuse of the catalysts.

Distinctive features of the invention are:

1) use as catalysts for obtaining DAS mixtures phosphomolybdenum CCP with a total molar ratio of Mo:P=3-12 without their separation into components;

2) use for the synthesis of catalysts as initial reagents MoO3and phase composition of the P2O5xMoO3(x=6 24);

3) preliminary mechanical activation of the starting reagents.

Activity phosphomolybdenum catalysts were tested in the synthesis of DAS, as in [2]

The invention is illustrated by the following examples.

Example 1. 20 g MoO3subjected to mechanochemical activation in a centrifugal planetary mill at a speed of 10-1within 20 minutes Then MoO3suspended in 400 ml of water, add 7,72 ml H3PO4the concentration of 3 mol/l Molar ratio of Mo:P 6. The suspension is stirred at 20oC 30 min, when ATEs DAS lead cooled reactor with a volume of 20 l, equipped with a mixer and apparatus of Sexlet. In a reactor placed in 15 l of acetone, 1 kg sorbose and the catalyst, and to the office of Sexlet load 10 kg of brand zeolite NaA. Include the heating of the reactor and bring mixture to a boil. The stirring at the boiling is continued for 3 hours. Then the stirring is stopped, the reactor is cooled to -20oC and incubated for 0.5 hours, the Reaction mixture is neutralized 20% ammonia solution to pH 8. From the solution is distilled acetone. To the syrup add 5 l of water, then distilled under vacuum 3 l of water with oxide of mesityl. From the aqueous solution DAS extracted with dichloromethane (2 x 10 l). The extract is evaporated to dryness and receive 1,156 kg DAS (yield 80%).

To identify the product using the method of gas-liquid chromatography. Conditions: column 2 m x 3 mm, filled with phase 10% PEG-3000 on chromaton N-AW granulation 0,2 0,25 mm, acid washed, the temperature of thermostat 195oC, the temperature of the evaporator 250oC, 60 ml/min (N2sensor ionization in the flame. The analysis confirmed that the selected product DAS.

Example 2. 20 g MoO3subjected to mechanochemical activation as in example 1. Then MoO3suspended in 200 ml of water, add 5,15 ml H3PO4the concentration of 3 mol/l Molar is adowanie green solution. The solution is evaporated to dryness and get the dry catalyst.

The activity of the catalyst in the synthesis of the DAS test as in example 1. Get 1,228 kg DAS (yield 85%).

Example 3. 20 g MoO3subjected to mechanochemical activation as in example 1. Then MoO3suspended in 40 ml of water, add 3,86 ml H3PO4the concentration of 3 mol/l Molar ratio of Mo:P 12. The suspension is heated to boiling and stirred for 2 min, with MoO3completely dissolves. The solution is evaporated to dryness and get the dry catalyst.

The activity of the catalyst in the synthesis of the DAS test as in example 1. Get 1.3 kg DAS (yield 90%).

Example 4. 20 g MoO3subjected to mechanochemical activation as in example 1. Then MoO3suspended in 200 ml of water, add 15,44 ml H3PO4the concentration of 3 mol/l Molar ratio of Mo:P 3. The suspension is stirred at 60oC 10 min, while MoO3completely dissolves with the formation of a green solution. The solution is evaporated to dryness and get the dry catalyst.

The activity of the catalyst in the synthesis of the DAS test as in example 1. Get 1,055 kg DAS (yield 73%).

Example 5. Get catalyst and use the dry. The dry residue is calcined at 600oC for two hours and receive a 20 g phase composition of P2O519MoO3. Phase is subjected to mechanochemical activation as in example 1. The powder was dissolved in 100 ml of water under stirring at 50oC for 15 minutes a Solution of green evaporated to dryness and get dry catalyst with a molar ratio of Mo:P 9.

The activity of the catalyst in the synthesis of the DAS test as in example 1. Get 1,228 kg DAS (yield 85%).

Example 6. Get catalyst and use it in the synthesis of DAS, as in example 3. The aqueous solution remaining after extraction DAS dichloroethane, evaporated to dryness. The dry residue is calcined 2 hours at 600oC and receive a 20 g phase composition of P2O524MoO3. Phase is subjected to mechanochemical activation as in example 1. The resulting powder was dissolved in 100 ml of water under stirring at 20oC for 30 minutes the Solution is evaporated to dryness and get dry catalyst with a molar ratio of Mo:P 12.

The activity of the catalyst in the synthesis of the DAS test as in example 1. Get 1.3 kg DAS (yield 90%).

Example 7 (comparative, prototype [4])

20 g MoO3suspended in 400 ml of water, add 7,72 ml H3PO4Cohn who walk not less than 10 hours the Solution is evaporated to dryness and receive a catalyst containing 30 to 60% GCA H6P2Mo18O62formed due to the significant duration of the synthesis.

The activity of the catalyst in the synthesis of the DAS test as in example 1. Get 0,867 kg DAS (yield 60%).

With increasing ratio of Mo:P > 6 dissolution MoO3when 100oC is only partially (to achieve a relationship of Mo:P 6).

Example 8 (comparative). The phase composition of the P2O518MoO3get as in example 4, but not subjected to mechanochemical activation. The powder is stirred in 200 ml of boiling water. After 10 h in the solution passes for 67% of phase with the achievement of relationships Mo:P 6. Remaining in the sediment MoO3dissolve fails. Thus, without the prior mechanochemical activation phase to regenerate phosphomolybdenum the catalyst with the ratio of Mo:P > 6 impossible, and regeneration of catalysts with Mo:P=3-6 connected with great energy.

As seen from the above examples, the use of phosphomolybdenum catalysts allows to increase the output of the DAS to 90% and use for their synthesis mechanochemical activation can dramatically reduce the time of synthesis, reduce energize the 6-diisopropylidene--L - carbofuran based on heteropolyacids, characterized in that it is a mixture of phosphomolybdenum heteropolyacids with a total molar ratio of Mo to R=3 12.

2. The method of preparation phosphomolybdenum catalyst under item 1 for 2,3:4,6-diisopropylidene-a-L-carbofuran by dissolving in water or a solution of phosphoric acid starting compounds of molybdenum at 20 - 100oC and the concentration of the parent compounds 5 to 50 wt. with subsequent evaporation of the solution to dryness, characterized in that the starting compound previously subjected to mechanochemical activation.

3. The method according to p. 2, characterized in that as starting compound used molybdenum oxide MoO3or phase composition of P2O5jmoo3(x 6 24).

 

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