DE1768475B2 - Process for the preparation of 2-chlorobutadiene (1,3) - Google Patents

Description

The method can carried out batchwise Ka ^S In this case, a substantial excess ■ 'Λ should β of the hydroxide on the ER for the reaction ^ j AirVe menee be used. When used wenigf forderiKDc ^ £ equivalents of hydroxide in an S stcns J ¹ at least 50%,

T ^K ° fta aSS «not necessary during the

- ¹ ^ ZZ more hydroxide to add, since the EndiStration is at least 25%. Hierduxh ^{is; k} 5i 2-chlorobutadiene- (l, 3) quickly from 3,4-di-ί Ί, Hnen'l with a relatively low yield

- ^C nJnJnJndes l-chlorobutadiene- (U) to produce, * ^at B eTen Umsau _VO n 90 to 100% in one hour

To achieve jr SSW. The optimum Molverhälinis Hvdroxvd to halogen-containing organic encryption TH depends on the Ausgang.matenalien vcm and catalyst, it is jedcch unädΓ £ β "Whether" 20: 1, 'n. general branches 3: 1 or 4:? or, as it is from S eShilich, 8: 1, 9: 1 and 10: 1 continuous processes, it is important.

Concentration in the catalytic reactions in the Geesatz to the influence of a change in Concentration in the non-catalytic comparison reaction.

The usual in such dehydrohalogenous reactions catalysts used, e.g. B. those in US-PS 23 22 258 and 30 79 446 mentioned Catalysts are gee.gnei for the purposes of the invention. Quaternary ammonium are preferred

catalogs, e.g. those in the German patent 16 18 790 of the applicant and Pol> äthyknglykol. The amounts used depend on the particular materials. Be.spie., - wh.se are suitable already 0.01% of the most effective catalysts

and optionally up to 5 or even 10 _o , based on the weight of the organic starting materials

The temperatures are preferably in the range from 40 to 70 ° C, but can also be. other / teroperatures worked down to 0 C, for example .0 become. The higher the temperature, the higher the temperature the rate of reaction and before amounts of

SSit ti ?, sr ?, ä ^

Po ^ erisu.ion ^ hibiu.rp »ie

Invention, the catalyst being 0.86 percent by weight (curve B) and 4.2 percent by weight (curve C) of a polyethylene glycol with an average molecular weight of 200 (commercially available under the name range.

B e 1 s ρ 1 e 1 1

is based on those listed in Table 1 below

Kon; enSo? jkau ^

the specialist could drive, not to conclude that one surprising beneficial effect on sales by increasing the concentration to 25 or 30 " was crz.ell in a catalytic process

Fig. 2 is a graphical representation of the proportion of 1-^ Chlorbuladien- in percent (1.3) (bezöget ,, on the weight of the 2-Chlorbutad.en- (1.3)), n Abhlngigkeit of the Ahrangskonzentrat.onen of N-triumhydroxyds at the same reactions. The curves, B and C correspond to the curves Λ ß and of Fig. 1 and vcranschaul.chcn d, c surprising decrease in the formation of undesired 1-chlorobutadicn- (1,3) as a by-product with a triumphant.

^e 'f "

W'e " _from ^ _κ ^ _η

. ^D ^ ^L _c "; In the _{introduction of sodium hydroxide in the flask, this is poured} into the above-mentioned solution in the" J- ^olDcn stirrer ".

Re M. on.ujjper J ^ «g _{lorbutent the one ger} in _g e stc; ^wor ^^ _{ia7J1 (002 to O} .l ^0. "based on MP 2" ut ¹ ^) and also the catalyst ent-3 4 ijichlornu in the reflux condenser

Jj ^. by the Kp _{agitator wjrd each dn} _

Piston ^ c _gel η Rcakl io "ste _m temperature select-

g sd ^ Hel d « _Rcakll0nS7C . _it maintained rend the called

(The reaction time is measured from the resumption of stirring.) After the stated reaction time has elapsed the stirrer is switched off, the flask is removed from the bath and the reaction mixture with diluted in cold water. The reaction mixture is made with toluene in twice the amount of the original used dichlorobutenes and the organic layer separated and filtered by gas chromatography

Table I.

analysis. The analysis values in percent area are derived from previously determined calibrations in Converted mole percent.

It should be noted that experiments 2 and 8 were not carried out according to the invention, since in In both cases the NaOH concentration was outside the prescribed limits, and that in this case the Results were correspondingly bad.

Ver catalyst catalyst NaOH- NaOH / Tempe Reak Calculated DCB- search Concentration DCB-MoI- rature tion time NaOH end sales No. tration too relationship to Concentration Beginning Beginning under the Acceptance of 100% DCB sales (%) (%) ( ⁰ Q (Min.) (X) 1 2 3 4th 5 6th 7th 8th 9

Ta Vci

1 Polyethylene glycol, 1 50 2.1 60 45 30th 98.3 Molecular weight 200 ("Carbowax 200", Union Carbide Corp.) 2 the same 0.87 20 * 9.8 60 30th 18 * 26.1 3 the same 0.87 40 9.7 60 30th 37 100 4th the same 4.2 30th 9.3 60 30th 27 94.9 5 Polyethylene glycol 0.22 50 10 50 5 46 98.7 6th Triethylene glycol 1.7 50 8.3 50 2 45 95 7th Dipropylene glycol 8.7 50 8.3 50 20th 45 96 8th the same 8.7 25 * 10 50 20th 23 * 11th 9 Polypropylene glycol, 1.7 50 8.3 50 2 45 91 Molecular weight 250 10 Triethylene glycol, 0.9 50 4.1 50 20th 41 98 Monomethyl ether 11th Diethylene glycol 4.3 50 8.3 50 20th 45 99 Monobutyl ether 12th Pentaethylene glycol 1.7 50 8.3 0 5 45 99.8 13th the same 1.7 50 8.3 25th 2 45 99.8 14th 2,3-butanediol 8.7 50 10 60 15th 46 94 15th Tetrahydro-2-pyran 8.7 50 10 60 15th 46 99 methanol 16 2-ethoxyethanol 6.4 50 10 60 30th 46 99 17th 2-methoxyethanol 4.3 50 10 60 15th 46 99 18th l-methoxy-2-propanol 8.7 50 10 60 15th 46 99 19th Diethylene glycol, 8.7 50 4.1 50 20th 41 99 Ethyl ether

*) Does not correspond to the invention.

Example 2

Another series of experiments were carried out under the conditions given in Table II as follows: One equipped with a jacket, stirrer, thermometer, reflux condenser and nitrogen inlet tube 500 ml, four neck, round bottom flask is purged with nitrogen. The inside of the flask is kept under nitrogen throughout the reaction. That Sodium hydroxide and the catalyst are added to the flask. While stirring slowly, the The contents of the flask are heated to 65 ° C. The speed of the stirrer is increased to 1300 rpm, and off a dropping funnel are 50 g of 3,4-dichlorobutene-l, containing 0.02 percent by weight phenolthiazine, added to the flask. The reaction will be 15 minutes carried out at 65 C. The flask is then quickly cooled to OC. After adding cold toluene the aqueous phase and the organic phase are separated, and the aqueous phase is three times with Toluene extracted. The toluene extracts are combined and analyzed by gas chromatography as in Example 1. The sales achieved are below in Table II given.

Table II

Ver
search
No. catalyst Catalyst NaOH
Concentration
tration too
Beginning
(/ ") CA) 50 NaOH / temperature
DCB-Moire
relationship to
Beginning
( ⁰ C) 65 Reak
tion time
(Min.) Calculated
NaOH end
concentration
under the
Acceptance of
100% DCB
sales DCB
Ums;
(%) 20th Octaltrimethyl
ammonium chloride 1 50 2 65 15th 29 89.1 21 Octadecyl trimethyl
ammonium chloride 1 For this 1 sheet 2 drawings 15th 29 99.4

Claims (2)

games described, little or no water is used. The concentrations of the aqueous claims: Sodium hydroxide vary from 80 to 46%, with the sodium hydroxide in a stoichiometric 1. Process for the production of 2-chlorobuta- 5 portion or at most in a small excess diene- (1,3) is present by dehydrochlorination of 3,4-di- (less than 1.2 equivalents). From the anchlorobutene-1 with aqueous alkali hydroxide in reports, it was confirmed that when using this Presence of a catalyst, resulting in quantitative ratios of the reactants themselves indicates that the dehydrohalo- a catalytic reaction like this becomes sluggish and too Generation with alkali hydroxide with an initial low conversion results when the sodium hydroxide concentration of at least 30%, based on these concentrations. Cons of this the weight of alkali hydroxide and water, recommended non-aqueous process type are the the final concentration being at least 25% violent and sudden nature of the reaction, from which carries, performs. difficulties in mastering the reaction 2. The method according to claim 1, characterized marked 15 tion temperature (as referred to in US-PS 25 43 648, that the alkali concentration as described), difficulties in handling and completion of the reaction above 25% and during the recovery of the solid sodium hydroxide and total response time over 20%, preferably poor responsiveness, because that over 25%. Sodium chloride formed the effect of the solid 20 sodium hydroxide suppressed. In US-PS 30 79 446 it is proposed that the reaction in the presence of water and an organic Solvent, namely a polyether. an ether alcohol, polyglycol or water-soluble 25 cyclic ether. At least some the> he organic solvents are among the catalysts mentioned in LS-PS 23 22 258. Of the Alkali content is between equimolar and 2: 1. It In a known dehydrohalogenation process it is indicated that a substantial excess of alkali ren, e.g. B. for the production of \ on2-chlorobutadiene- (1,3), 30 is not necessary. Evaluated in the examples halogen-containing organic compounds, e.g. B. written experiments is a practically stoichiome-3,4-dichlorobutene-l, reacted with sodium hydroxide. trical amount of alkali used. The alkali is in Although this process has been at a concentration of 50 "; to a mixture for at least 30 years is available, there has not yet been a large amount, which is already a relatively large one for the production of 2-chlorobutadiene (l, 3) an 35 contains amount of water, so that the alkali in the reaction found. The US-PS 20 38 538 suggested original mixture is always available in diluted form originally a non-catalytic process is consumed and more or less immediately consumed. Turning of solid potassium hydroxide without a water- as a reason for using such a large one medium before. The US-PS 24 30 016 describes the amount of water is indicated that this as a minor nichlkatalytisches process in which the aqueous 40 product formed sodium chloride is kept in solution Alkali is to be consumed in excess at an elevated temperature. turns, dichlorobutene in about the amount in which Hs has now been found that an unexpected it is consumed, added and the 2-chlorobuta- part when carrying out a catalytic merit (1,3) is distilled off as it is formed. Although it is stated that the concentration of 45 during the entire reaction with a higher aqueous alkali can be between 1 and 30%, the concentration is kept as maneuverable as has been necessary up to now for all experiments described in the examples was deemed. As carried out during the reaction at a concentration of 10%. Is formed by water, the concentration of the in own experiments has now been confirmed that with each moment remaining hydroxide by the non-catalytic process, as in US-PS 5 ° amount of water that has been formed, as well as by 24 30 016 is described, the conversion to 2-chloro affects previous alkali consumption.
butadiene- (l, 3) decreases when you add the alkali concentration- the subject of the invention is accordingly a tion increases from 10 to 25 and 30%. At 30% drive to the production of 2-chlorobutadiene- (l, 3) the conversion is so low that it is economically unintentional by dehydrochlorination of 3,4-dichlorobutene-1 is interesting. It was also found that the proportion of 55 with aqueous alkali hydroxide in the presence of a 1-chlorobutadiene (1,3) as an undesirable secondary pro-catalyst, which is characterized in that In general, with increasing alkali concentration, dehydrohalogenation with alkali hydroxide occurs tion zuiii-.int. From this it is obvious why with an initial concentration of at least 30%, a non-catalytic process as described in the based on the weight of alkali hydroxide and US-PS 24 30 016 is described, a low concentration of 60 water, the final concentration at least 25% concentration of 10% is preferred and higher concentration is carried out. centrations, e.g. B. 25 and 30%, preferably. The concentration is during at least one be avoided. Part of the reaction is preferably kept above 15 " . The US-PS 23 22 258 describes a catalytic As a hydroxide is usually and preferably Process in which polyhydric alcohols and sodium hydroxide are used, but kadroxyether can also be used are used as catalysts, and lium hydroxide or any other alkali hydroxide that indicates that the presence of water is able to carry out the reaction tends to inhibit the reaction. In the in the by- be.