FR2484999A1 - Chlorohydrin prodn. from olefin(s) or diene(s) - by electrolysis with aq. acidic chloride soln. - Google Patents

Abstract

Prodn. of 3-5C satd. mono- or dichlorohydrins (I) from 3-5C olefins or dienes (II) is carried out by contacting (II) with an aq. HCl or acidic alkali(ne earth) metal chloride soln. having a chloride ion concn. of 1-4 g-ion/l, and electrolysing the soln. at an anodic current density of 0.10-0.30 A/square cm and a temp of 40-75 deg.C. (I) are useful as intermediates for mono- and diepoxides. The process gives high yields without the need for prior prodn, compression and transportation of Cl2. Suitable starting materials (II) are allyl chloride, 1,3- butadiene, isoprene and 1,3-pentadiene. Electrolysis can be effected in a cell with or without a diaphragm. Suitable electrode materials are graphite and Pt.

Description

 The present invention relates to the preparation of chlorinated organic compounds, and in particular relates to a process for the preparation of saturated mono- or diatomic chlorinated alcohols, in particular with a number of carbon atoms from 3 to 5. The chlorinated alcohols indicated are widely used in particular for the production of substances of practical interest, such as for example propylene and epichlorohydrin oxides, used for obtaining macromolecular compounds, namely: chlorinated plasticizers, polyesters, polyurethanes, epoxy adhesive; for the production of diene dioxides used in the synthesis of dyes, erythrite, to improve leather.

Chemical processes are known for the preparation of saturated mono-or diatomic chlorinated ancoSs, with a number of carbon atoms from 3 to 5, by chlorhydroxylation of unsaturated hydrocarbons with a number of carbon atoms from 3 to 5, containing a or two double bonds, with hypochlorous acid.

 Thus, according to one of the known chemical processes, the glycerin dichlorohydrins are obtained by hydrochloroxylation of allyl chloride with hypochlorous acid.

In this process, hypochlorous acid is not prepared beforehand, but two processes are brought together: preparation of hypochlorous acid and hydrohydroxylation of allyl chloride in a single process, simultaneously admitting allyl chloride and chlorine in water The yield of the targeted product is 54%, calculated with respect to chlorine (Japanese patent no. 38408, volasse 16 B 669 published in 1972).

Under analogous conditions, the divinyl hydrohydroxylation leads to obtaining dichlorobutanediol with a yield of targeted product equal to 57% calculated with respect to chlorine (Przemysl chemiczny, vol 55s N5, 1976,
Warsaw: MD Stojanova - Antoszczyszyn et al. "Badania nad selektrywnym sterowaniem reakcja chlorohydroksylowania butadienu w kierunku dwuchlorobutanodiol", p.202-205).

The methods described above require prior preparation of the chlorine, followed by its purification, compression and transfer to the reaction zone.

In addition, the yield of chlorinated alcohols, sufficiently high at the start of the process, for example in the case of the preparation of glycerin dichlorohydrins, decreases progressively, since in parallel with the formation of the main product a stschiometric amount of hydrochloric acid is formed , the amount of which increases in proportion to the concentration of chlorinated alcohols, for example glycerin dichlorohydrins.

The increase in the hydrochloric acid concentration inhibits the hydrochloric hydroxylation process, so that when the concentration reaches 5%, the selectivity of the process decreases considerably and the content of side reaction products increases sharply. To prevent the formation of such products, in particular trichloropropane when glycerin dichlorohydrins are prepared, silver perchlorate is added to the reaction mixture. The yield of glycerin dichlorohydrins then increases insignificantly and, obviously, the cost price of the targeted product increases significantly. In addition, the use of lost hydrochloric acid presents a problem that has not been solved so far.

Another chemical process is also known for preparing glycerin dichlorohydrins by hydrochloroxylation of allyl chloride with refnti hypochlorous acid (below 150C, preferably up to 6-80C); the temperature of the reaction mixture at the outlet of the reactor must not exceed 400C (author's certificate
USSR, No. 289078, class C07 C, 31/22, "Bulleten otkryty, isobreteni, promyshlennych obraztsov i tovarnykh znakov" nl, published February 8, 1972). However, during the pre-preparation of hypochlorous acid, an equimolar amount of hydrochloric acid is inevitably formed, the use of which, as mentioned above, presents difficulties. the preparation of a tonne of glycerin dichlorohydrins, 4 tonnes of hydrochloric acid are formed (calculated with respect to the acid at 27%).

 The present invention proposes to eliminate the drawbacks mentioned.

 In the process for the preparation of saturated mono- or diatomic chlorinated alcohols with a number of carbon atoms from 3 to 5, it has been decided to choose conditions for the hydrochlorination of unsaturated hydrocarbons with a number of carbon atoms of 3 to 5, containing one or two double bonds, which would make it possible to obtain the chlorinated alcohols with a high yield and a degree of purity, to simplify the process, in particular to eliminate the need for obtaining chlorine beforehand, its compression and its transfer to the reaction zone, as well as using the lost hydrochloric acid that forms in the process.

 The solution consists in a process for the preparation of saturated mono- or diatomic chlorinated alcohols, in particular with a number of carbon atoms from 3 to 5, by chlorhydroxylation of unsaturated hydrocarbons with number of carbon atoms from 3 to 5 , containing one or two double bonds, characterized, according to the invention, in that the hydrohydroxylation of said unsaturated hydrocarbons is carried out during the electrolysis of an aqueous solution of hydrochloric acid or acid solutions of metal chlorides alkaline and / or alkaline earth, admitting said unsaturated hydrocarbons in said indicated solutions, and carrying out electrolysis at a chlorine ion concentration of said solutions from 1 to 4 gram ions per liter, an anodic current density of 0 , 10 to 0.30 A / cm2, and a temperature of 40 to 750C.

 The proposed process is simple from a technological point of view in comparison with known chemical processes, because it makes it possible to exclude the prior preparation of chlorine, its compression and its transfer into the reaction zone, since chlorine is formed during the electrolysis with which the hydrochlorination of unsaturated hydrocarbons takes place simultaneously. In addition, the process in question makes it possible to obtain the targeted products with a high degree of purity6, with a high yield (up to 91 l following the flow, which corresponds to the yield calculated relative to chlorine in the chemical process ) and with high process selectivity (up to 98%).

The invention will be better understood and other objects, details and advantages thereof will appear more clearly in the light of the explanatory description which follows of an embodiment given solely by way of nonlimiting example.

 The process according to the invention is based on the following reactions.

During the electrolysis of the electrolyte constituted by an aqueous solution containing chlorine ions (that is to say an aqueous solution of hydrochloric acid or acid solutions of chlorides of alkali and / or alkaline-earth metals), it becomes forms hydrogen on the cathode and chlorine on the anode:
2 H + + 2 é - H2 (1) on the cathode
2Cl + 2 é rC12 (2) on the anode
Chlorine reacts with water, forming hypochlorous acid:
C12 + H2O # HClO + HCl (3).

The hydrochloric acid obtained is used for the subsequent formation of chlorine according to reaction (2) (that is to say that the present invention makes it possible to solve the problem of the use of lost hydrochloric acid) and the hypochlorous acid enters into a hydrochloride reaction with the unsaturated hydrocarbon, for example allyl chloride: 2 HClO + 2 CH2 = CH-CH2CL- + CH2C1-CHOH -CH2Cl + CH20H-CHCl-CH2Cl
(4)
Thus, hydrogen is the only waste resulting from the proposed process.

 As mentioned above, electrolysis is carried out, according to the invention, at a chlorine ion concentration of the electrolyte of 1 to 4 gram ions per liter, an anodic current density of 0, 10 to 0.30 A / cm2, and a temperature of 40 to 75 C.

 When the chlorine ion concentration of the electrolyte is less than 1 gram ion per liter, there is a significant release of oxygen, the resistance of the anodes decreases as well as the yield of targeted products.

On the other hand, when the chlorine ion concentration of the electrolyte is greater than 4 gram ions per liter, the yield of targeted products decreases as a result of the formation of secondary organo-chlorinated products not containing hydroxyl groups.

When the anodic current density is greater than 0.30 A / cm2, the yield of targeted products decreases appreciably as a result of the losses (no) of free chlorine, which escapes from the electrolyser with the waste gases.

Anodic current dentistry less than 0.10
A / cm2 is disadvantageous from the economic point of view, since the efficiency of the electrolyser then suddenly decreases.

If the temperature of the electrolysis exceeds 750C, the atomization of the initial unsaturated hydrocarbons by means of a dispersing device becomes difficult during their admission into the electrolyser, which results in a reduction in the reaction rate (4) and the passage of free chlorine to the atmosphere.

At electrolysis temperatures below 400C the reaction rate (4) decreases and the non-reacting chlorine escapes to the atmosphere.

In the process proposed as electrolyte, it is possible to use hydrochloric acid at 1 = 4 N of any quality, or acid solutions of chlorides of alkali and / or alkaline earth metals, for example acid solutions of sodium, potassium, lithium, magnesium, calcium, strontium chlorides. Said acid solutions are a mixture of an aqueous solution of any mineral acid (except nitric acid) and aqueous solutions of said salts. In each of the cases described, the total concentration of chlorine ions is chosen within the limits of 1 to 4 gram ions per liter of electrolyte.

As unsaturated hydrocarbons having a number of carbon atoms from 3 to 5, containing one or two double bonds, it is possible to use, for example, allyl chloride, divinyl (1,3-butadiene), l isoprene (2-methylbutadiene-1, 3), piperylene (1,3-pentadiene).

 According to the proposed method, electrolysis can be carried out both in a diaphragm electrolyser and in an electrolyser without diaphragm. The electrodes can be of any material stable to the action of dilute hydrochloric acid and chlorine under the conditions of electrolysis, for example graphite or platinum.

 The process in question for the preparation of saturated mono- or diatomic chlorinated alcohols having a number of carbon atoms from 3 to 5 is carried out as follows.

 Into a standard electrolyser without diaphragm, 50 mm in diameter and 200 mm in height, containing graphite electrodes, 1N hydrochloric acid is poured in. The temperature is then brought to 60 - 650C and it begins to pass allyl chloride vapors through a dispersing device. Then apply the DC voltage and adjust the intensity of the current so that the anodic current density is within 0.10 to 0.30 A / cm2. The speed of admission of allyl chloride is adjusted so that 10 g of olefin are consumed for each 7.5 A / hour.

If the temperature of the electrolyte rises above 650C, a cooling system is connected and the temperature is kept within limits of 60 to 650C.

Hydrogen and chlorine are formed during electrolysis. Chlorine reacts with water according to reaction (3), obtaining hydrochloric and hypochlorous acids. The hydrochloric acid resulting from this reaction is used for the subsequent formation of chlorine, and the hypochlorous acid reacts with allyl chloride following reaction (4) with the formation of glycerin dichlorohydrin.

 The waste gases leaving the electrolyser and consisting of a mixture of hydrogen and allyl chloride are admitted with the vapors of hydrochloric acid solution in a reflux condenser, where the vapors of hydrochloric acid solution condense . The condensed hydrochloric acid solution is brought back into the electrolyser, and the mixture of hydrogen and allyl chloride, after having passed through the refrigerant, separates into gaseous hydrogen and into liquid allyl chloride. The latter is returned to an evaporator and then to the electrolyser. The hydrogen passes through an aqueous solution of potassium iodide, which is an indicator of the presence of chlorine, and is then burned.

Other characteristics and advantages of the invention will be better understood on reading the description which follows of several concrete but non-limiting examples of embodiment. In all these examples, the chlorine in the waste gases exiting the electrolyser is absent.

 Example 1.

800 ml of electrolyte consisting of a hydrochloric acid and an aqueous solution of chloride sodium in a ratio such that the total concentration of chlorine ions in the electrolyte is 4 gram ions per liter. The temperature of the electrolyte is then brought to 600 ° C. and vapors of allyl chloride are passed through the anode chamber through a dispersing device. Apply a DC voltage and adjust the intensity of the current so that the anadic current density is 0.30
A / cm2. The speed of supply of allyl chloride is adjusted so that 10 g of olefin are spent by 7.5
Ah, electrolysis is carried out for 1 hour.

 The current yield (which is equivalent to the chlorine yield in the chemical process) of glycerin dichlorohydrins is 91% (15.1 g), 4% of the current is spent on the release of oxygen (63 ml), 2.5% for the formation of oxygen-containing chlorine compounds (P, 006 gram equivalent), and 2.5% for the formation of trichloropropane (0.48 g).

Example 2.

Into a dynamic polytetrafluoroethylene ("Teflon") electrolyser without diaphragm, with a capacity of 3.5 liters, 3 liters of electrolyte are poured consisting of a mixture of hydrochloric acid and aqueous sodium chloride solution (total content of chlorine ions of the electrolyte: 2.8 gram ions per liter). 32 g of divinyl (1,3-butadiene) are passed at a temperature of 50 ° C., at an anode current density of 0.25 A / cm 2 and at a current intensity of 30 A. The electrolysis lasts 2 hours.

 The product obtained is isolated by vacuum distillation after removing the water by distillation.

 It was found, by argentometric titration, that after the onx reaction obtained 85.6 g of dichlorobutanediol (current yield 89%). The dichlorobutanediol obtained consists, according to the chromatographic analysis, of a mixture of isomers: 51% by weight of 1,4-dichlorobutanediol, 24% by weight of 1,3-dichlorobutanediol and 25% by weight of 1,2- dichlorobutanediol. In addition to dichlorobutanediol, 1.05 g of 1,2-dichlorobutene and 2.5 g of 1,4-dichlorobutene were obtained (current yield 0.75 and 1.8% respectively), 4 g of 1.2. , 3, 4-tetrachlorobutane (current yield 3.6%), 1.5 g of HCl03 (current yield 1.6%), traces of Cl04, ig of C02 (current yield 1%) and 0, 25g of 2 (current yield 1.4%).

Example 3.

Under the conditions of Example 2, but without sodium chloride, 50.7 g of dichlorobutanediol are obtained from 32 g of divinyl, the content of chlorine ions in the electrolyte being 1.1 gram ion per liter.

 There were also obtained, following the reaction, 3.1 g of 1,2-dichlorobutene and 6 g of 1,4-dichlorobutene (current yield 2 and 4% respectively), 13.9 g of 1, 2 , 3, 4-tetrachlorobutane (current yield 12.5%), 12g HClO3 (current yield 12.5%), 12 g HCl04 (current yield 7.5%), 5 g C02 (yield 5.1% current), 0.3 g of 2 (current yield, about 2%).

 Example 4.

 The process is carried out under the conditions of Example 2, except that the total concentration of chlorine ions in the electrolyte is 4 gram ions per liter.

 The results are similar to those of Example 2.

Example 5. Comparative $)
Electrolysis is carried out under the conditions of Example 2, but the total concentration of chlorine ions in the electrolyte constitutes 5 gram ions per liter.

 Finally, 64 g of dichlorobutanediol (72% current yield), 5 g of 1.20 and 1,4-dichlorobutenes (3.6% current yield) and 22 g of 1,2,3,4 tetrachlorobutane are obtained. current 20%).

Thus, the increase in the concentration of chlorine ions in the electrolyte above 4 gram ions per liter leads to a considerable yield of secondary products and to a corresponding significant reduction in yield.
Example 6. (comparative)
Electrolysis is carried out under the conditions of Example 2, but the total concentration of chlorine ions in the electrolyte constitutes 0.7 gram ions per liter.

 68 g of dichlorobutanediol are obtained (current yield 77%), 1 g of 1,2- and 1,4-dichlorobutenes (current yield 1.5%), 4 g of 1,2,3,4-tetrachlorobutane ( current yield 3.8%), 3 g HCl03 (current yield 3.2%), 6 g HCl04 (current yield 3.6%), 5 g C02 (current yield 5.1%) , 0.6 g of O2 (current yield 4%).

 Thus, the reduction in the chlorine ion concentration of the electrolyte above 1 gram ion per liter leads to a reduction in the yield of the targeted product.

Example 7. (comparative)
The electrolyte is conducted under the conditions of Example 2, but at the temperature of 8O0C.

 71 g of dichlorobutanediol are obtained (current yield 80 96), 4 g of 1,2-and 1,4-dichlorobutenes (current yield 2.8%), and II g of 1, 2, 3, 4- tetrachlorobutane (current yield 10%).

As can be seen from the test results, the yield of by-products increases at temperatures of 800C and above.

 Example 8.

 Electrolysis is carried out under the conditions of Example 2, but at the anodic current density of 0.30 A / cm2.

 73 g of dichlorobutanediol are obtained (current yield - 78%), 5 g of 1.2 and 1,4-dichlorobutenes (current yield 5.5%), 15 g of 1,2,3,4-tetrachlorobutane (current efficiency of about 13.5).

 Example 9.

 Electrolysis is carried out under the conditions of Example 2, but at the temperature of 6O0C. 82.5 g of dichloroisopentanediol are obtained (current yield 84%) from 40 g of isoprene (2-methylbutadiene). -1.3).

In addition to dichloroisopentanediol, 3.1 g of 1,2-dichloroisopentene and 1.5 g of 1,4-dichloroisopentene (2 and 1% current yield respectively), 5.9 g of 1.2 are obtained. , 3, 4-tetrachloropentane (current yield 5%), 2 g HCl03 (current yield 2%), 5.6 g HCl04 (current yield 3; 5%), 1 g C02 (current yield 1%) and 0.27 g of 2 (current yield 1.5%).

 Example 10.

 Electrolysis is carried out in a manner analogous to that described in Example 2. 76 g of dichloropentanediol (current yield 78%) are obtained from 40 g of piperylene (1,3-pentadiene) at anodic density current of 0.30 A / cm2. In addition to the chlorinated alcohol, 9.2 g of dichloropentenes are obtained (current yield 6%), 9.1 g of tetrachloropentane (current yield 7.7%), 2.2 g of HClO3 (current yield 2, 3%), 6 g of HClO4 (current yield 3.8%), 1 g of CO2 (current yield 1%), 0.22 g of 02 (current yield 1.2%).

Example 11.

 The electrolysis is carried out under the conditions of Example 2, but instead of sodium chloride lithium chloride is used in an amount such that the total concentration of chlorine ions in the electrolyte is 2.8 gram ions per liter.

 The results obtained are analogous to those of Example 2.

 Example 12.

 The electrolysis is carried out under the conditions of Example 2, but instead of sodium chloride potassium chloride is used so that the total concentration of chlorine ions in the electrolyte is 5 gram ions per liter.

 The results obtained are analogous to those of Example 2.

Example 13.

 The electrolysis is carried out under the conditions of example 2, but instead of sodium chloride rubidium chloride is used so that the total concentration of chlorine ions in the electrolyte is equal to 3 gram ions per liter.

 The results obtained are the same as in Example 2.

 Example 14.

 Electrolysis is carried out under the conditions of Example 2, but instead of sodium chloride, magnesium chloride is used so that the total concentration of chlorine ions in the electrolyte constitutes 3 gram ions per liter.

The results obtained are analogous to those of Example 2.

Example 15.

 The electrolysis is carried out under the conditions of Example 2, but instead of sodium chloride, calcium chloride is used so that the total concentration of chlorine ions in the electrolyte is 3 gram ions per liter.

The results obtained are the same as in Example 2.

 Example 16.

The electrolysis is carried out under the conditions of Example 2, but instead of sodium chloride a mixture of strontium and barium chlorides (weight ratio 1/1) is used so that the total concentration of chlorine ions of the electrolyte is 3 gram ions per liter.

The results obtained are the same as in Example 2.

Example 17.

Electrolysis is carried out under the conditions of Example 1, but the anodic current density constitutes 0.10 A / cm 2.

 The results obtained are similar to those of Example 1.

 Example 18.

 Electrolysis is carried out under the conditions of Example 1, but the anodic current density constitutes 0.20 A / cm2.

 The results obtained are similar to those of Example 1.

Example 19. (comparative)
Electrolysis is carried out as in Example 1, but the anodic current density constitutes 0.50 A / cm2.

 There is a marked release of chlorine into the atmosphere. The yield of current targeted products is reduced to 80%.

Example 20. (comparative)
Electrolysis is carried out as in Example 1, but the anodic current density constitutes 0.05 A / cm2.

 The results are similar to those obtained in Example 1, but the efficiency of the installation drops at this current density, which is not advantageous from the economic point of view.

 Example 21.

 Electrolysis is carried out as in Example 1, except that the total concentration of chlorine ions in the electrolyte is 0.8 gram ions per liter.

 The results obtained are similar to those of Example 1.

Example 22.

 Electrolysis is carried out under the conditions of Example 2, but as an electrolyte, instead of the mixture of hydrochloric acid and aqueous sodium chloride solution, a mixture of sulfuric acid and aqueous solution is used. sodium chloride The concentration of SO42- ions in the electrolyte constitutes 2 gram ions per liter, that of chlorine ions, 4 gram ions per liter.

The results obtained are similar to those of Example 2.

Example 23.

The electrolysis is carried out under the conditions of Example 2, but as the electrolyte a mixture of phosphoric acid and an aqueous solution of potassium 3-chloride is used. The concentration of P04 ions in the electrolyte constitutes 1 gram ion per liter, that of chlorine ions, 4 gram ions per liter.

 The results obtained are analogous to those of Example 2.

Example 24.

 Electrolysis is carried out under the conditions of Example 2, but instead of sodium chloride, a mixture of sodium chloride and potassium chloride is used in a weight ratio of 1/1. The total concentration of chlorine ions in the electrolyte is 3 gram ions per liter.

 The results obtained are analogous to those of Example 2.

Example 25.

Electrolysis is carried out under the conditions of Example 1, but instead of sodium chloride, a mixture of potassium chloride and calcium chloride is used. The total concentration of chlorine ions in the electrolyte constitutes 4 gram ions per liter.

The results obtained are the same as in Example 1.

Example 26.

Electrolysis is carried out under the conditions of Example 1, the total concentration of chlorine ions in the electrolyte being 1 gram ion per liter.

 The results obtained are similar to those of Example 1.

 Example 27.

Electrolysis is carried out under the conditions of Example 1, the total concentration of chlorine ions in the electrolyte being 1.5 gram ion per liter.

The results obtained are the same as in Example 1.

 Example 28.

 Electrolysis is carried out under the conditions of Example 1, the total concentration of chlorine ions in the electrolyte being 2 gram ions per liter.

The results obtained are similar to those of Example 1.

 Example 29.

 Electrolysis is carried out under the conditions of Example 1, but the temperature is equal to 7TOC.

 The results obtained are the same as in Example 1.

Example 30.

 Electrolysis is carried out under the conditions of Example 2, but the temperature is maintained at 40 C.

The results obtained are analogous to those of Example 2.

 Of course, the invention is in no way limited to the embodiment described which has been given only by way of example In particular, it includes all the means constituting technical equivalents of the means described, as well as their combinations, if these are executed according to his spirit and implemented within the framework of protection as claimed.

Claims (2)

1. Process for the preparation of saturated monoatomic or diatomic chlorinated alcohols, with a number of carbon atoms from 3 to 5, by chlorhydroxylation of unsaturated hydrocarbons with a number of carbon atoms 3 to 5, containing one or two double bonds , characterized in that the chlorhydroxylation of unsaturated hydrocarbons is carried out during the electrolysis of an aqueous solution of hydrochloric acid or of acid solutions of chlorides of alkali and / or alkaline-earth metals, by admitting said hydrocarbons not saturated in said solutions and by carrying out electrolysis at a chlorine ion concentration of the above-mentioned solutions of 1 to 4 gram ions per liter, an anodic current density of 0.10 to 0.30 A / cm2 and a temperature of 40 to 750C. 2. Saturated monoatomic or diatomic chlorinated alcohols, in particular with a number of carbon atoms from 3 to 5, characterized in that they are obtained by the process which is the subject of claim 1.