DE1618754C - alpha-chloro-lauroyl peroxide and a process for its production - Google Patents

Description

example 1

The representation of the a-Chlorlauroylperoxids takes place in a cylindrical glass tube of 7 cm in diameter and 40 cm in height, which is at its lower end has a drain cock. The tube is provided with a cooling jacket for the flow of a cooling liquid equipped. It contains a tulip stirrer running at 150 rpm, a thermometer and a dropping funnel arranged.

In the tube, a 250 g water, 9.5 g NaOH and 67.5 g of NaCl is poured existing solution and - cooled to -10 ⁰ C. ^{15 cm 3 of} hydrogen peroxide solution with an H ₂ Os content of 334.5 g / l are then slowly poured in over a period of 5 minutes with stirring, the temperature being kept at -10 ° C.

A cooled mixture of 100 g of pure η-hexane and 50.4 g of α-chloro-lauroyl chloride is poured into the dropping funnel and this mixture is then poured into the reaction vessel with constant vigorous stirring at such a rate that the temperature is close to -10 ⁰ C remains. This takes 20 minutes.

Stirring is continued for 1 hour it, and in this case the temperature at -10 ⁰ C held, resulting in a fine stable suspension.

While stirring now very slowly, the reaction medium is progressively with a 5 n-hydrochloric acid neutralized, whereby the

The course of neutralization is monitored by measuring the pH. ^{About 4 cm 3 of} this acid are required to achieve a pH value of the order of magnitude of 6. If the phase separation does not take place easily, a little hydrochloric acid can be added, but this is not desirable in itself, because under these circumstances the fatty acid is liberated from the sodium salt which is formed at the same time as the α-chloro-lauroyl peroxide. This fatty acid then passes into the organic layer instead of remaining in the aqueous layer in the form of the sodium salt.

Now, the aqueous layer is separated off, poured on the organic layer in a cooled to a temperature of -10 ° C container, then dried by stirring with an amount of about 4 g of powdered anhydrous sodium sulphate and in a cooling chamber at a temperature of - 10 ⁰ C filtered into a tared container, which is then kept at a temperature of -20 ⁰ C. This gives 119.2 g of organic solution of the α-chloro-lauroyl peroxide.

The titer of the organic solution of the a-Chlorlauroylperoxids of peroxide, which can also be related to active oxygen, is used according to the determined by the iodometric method using the following procedure.

50 cm ^{3 of} pure isopropyl alcohol, 2 cm ^{3 of} a saturated solution of potassium iodide and 2 cm ^{3 of} pure acetic acid are placed in a 250 cm ^{3 Erlenmeyer bottle.} Then an amount between 0.7 and 1.5 g of the organic peroxide solution determined to the nearest ± 1 mg is added. The contents of the flask are now heated to a gentle boil for 2 minutes, then cooled and the iodine released is titrated with a n / 10 solution of sodium thiosulphate.

In addition, a blank test is carried out without the addition of the organic solution of α-chloro-lauroyl peroxide. The reaction sequence during the oxidation is schematically as follows:

R — C — O — O — C — R + H ₂ O

O O

2RCOOH + O

'O + 2 KJ + H ₂ O

“J ₂ + 2 KOH

2KOH + 2RCOOH

-> 2 RCOOK + H ₂ O

and for the titration:

I ₂ + 2 Na ₂ S ₂ O ₃
> 2NaI + Na ₂ S ₄ O ₆

consumed. The blank value was zero. It surrenders so:

Active content of the solution
Oxygen .... 1.006%

Content of the organic solution
a-chloro lauroyl peroxide 29.36%

Total weight of the _0Q " ₁₁₀ ~

holding peroxides = 35 g
IUU

Theoretical yield
α-chloro lauroyl peroxide

IUU

^{= 46} > ⁵¹ 8

An actual yield of 75.2% of theory is thus achieved.

A determination of the chlorine can be carried out at the same time as the determination of the active oxygen done by microanalysis. The chlorine content is usually very close to the theoretical in these cases Chlorine content is calculated based on the active oxygen and is for the above organic solution of α-chloro lauroyl peroxide 4.46%.

If the chlorine content is higher than this value, it is found that when the solution cools down Separate about - 23 ° C from these flakes.

As the analysis shows, these flakes do not contain active oxygen, but do have a chlorine content close to 15.1% and an acid number close to 238.8. As can be deduced from this, they consist of excess acidification of the reaction medium released during peroxidation α-chloro lauric acid.

It has also been found that the yield of α-Chlorlauroylperoxid at the expense of the formation of Sodium salt of the fatty acid by adjusting the stirring speed and the duration of stirring the shape of the reaction container can be improved.

Example 2

The procedure is as in Example 1, but the η-hexane by a mixture of 50 g Trifluorotrichloroethane and 50 g of petroleum ether (if ° = 0.644, boiling range 35 to 65 ° C) replaced. The stirring speed, which is initially 170 rpm, is after the addition of the acid chloride for a period of 20 minutes reduced. There are 132 g of organic solution with 0.946% active oxygen, i. H. one Solution obtained with a peroxide content of 27.61%.

The total weight of the peroxide obtained is 36.5 g, corresponding to a yield of 78%.

As can be seen, 10 ⁴ gram atoms of iodine correspond to 0.0008 g of active oxygen or 0.02335 g of α-chloro-lauroyl peroxide.

To carry out the determination, 0.8745 g of a-chloro-lauroyl peroxide solution were taken; during the titration, 11 cm n / 10 Na ₂ S ₂ O ₃ solution

Example 3

The procedure is as in the case of Example 2, but that used in Example 1 is also used aqueous solution replaced by the following mixture:

Water. '. 500 cm ³

NaOH 9.5 g

NaCl 144 g

The reaction medium is stirred after addition of the a-Chlorlauroylchlorids 1 hour at a speed of 150 rpm while maintaining a temperature of -1O ⁰ ^ C. It will

164 g of organic solution with a content of 37.7 g of α-chloro-lauroyl peroxide were obtained. The yield is 84%.

Example Γ4

The procedure is as in Example 1, but the η-hexane by a mixture of 50 g Petroleum ether and 50 g monofluorotrichloromethane replaced. Under these conditions there are 140 g of organic peroxide solution with a content of 1.417 g = 1.012% of active oxygen or 41.368 g recovered α-chloro lauroyl peroxide = 29.548%. Since the theoretically achievable amount of peroxide is 46.14 g, the yield is 89.6%.

In a cold chamber in which the temperature was -10 ° C, the heat of formation of the a-Chlorlauroylperoxids in the case of Example 2 used solvent mixture determined from petroleum ether and Trifiuortrichloräthan. As calorimetric The liquid used is pure n-butanol. The Q value is found to be 50 kg cal / mol.

The infrared spectrum of the solution of a-IR Chlorlauroylperoxyds in 30% pure η-hexane at a temperature of - examined mm 20 ⁰ C and a layer thickness of 0.1. At the same time, a cell containing pure η-hexane in a layer thickness of 0.8 mm was inserted into the reference beam at normal temperature and the spectrum of the pure η-hexane was used as the reference value.

The following tables give a comparison of the essential absorption bands in μ of the two peroxides in the range between 5 and 10 μ and their relative intensities st = strong, »M - .. medium and sw = weak.

Lauroyl peroxide α-chloro-lauroyl peroxide 5.52 st 5.48 st 5.60 st 5.58 st 7.08 bw 7.00 m 7.42 bw 7.40 m 8.88 m; ^: * < 8.6 m 9.50 st 8.9m 9.5 st

The absorption bands of the peroxide group in the range from 5.52 to 5.60 μ wavelength in the Spectrum of the lauroyl peroxide are, as can be seen, on the side of due to the presence of the Chlorine atom shifted shorter wavelengths in the α-chloro-lauroyl peroxide. ^

Furthermore, the half-lives of a 30% solution of the peroxide in hexane were three of each other measured at different temperatures. The curves produced by the iodometric measurements of the Changes in the solutions as a function of time indicated that the initial solution was about 30% α-chloro-lauroyl peroxide 50% of your active oxygen

at 20 ⁰ C in. 5 hours,
at 0 ⁰ C in 35 hours and
loses at -23 ° C in 675 hours.

Alpha-chloro lauroyl peroxide is particularly suitable as a supplier of active and free oxygen Radicals for all cases in which this task occurs.

Claims (2)

Patent claims:
1. α-Chlorlauroyl peroxide of the formula CH ₃ - (CH ₂ ) ₉ -CHCl-C-O IO 2. A process for preparing the compound of claim 1 from the appropriate acid chloride and sodium peroxide, characterized in that a solution of a-Chlorlauroylchlorid in a solvent for the peroxide at -10 ° C with vigorous stirring in an at - 10 ⁰ C prepared aqueous solution of sodium peroxide is poured in so slowly that the reaction ^{temperature is kept at -10 0} C, that one then stirs while maintaining this temperature for at least 20 minutes and that after neutralizing with weaker stirring to a pH of about 6, the organic phase at -1O ⁰ C the aqueous phase is separated off. , The invention relates to α-chloro lauroyl peroxide, and also to a process for its production. The σ-chloro lauroyl peroxide has the formula: I CHCl ~~ C O O C ClCH 35 and is manufactured in such a way that a solution of a-Chlorlauroylchlorid in a solvent for the peroxide at -1O ⁰ C with vigorous stirring in an in - pouring produced 10 ⁰ C aqueous solution of sodium peroxide is so slow that the reaction temperature at - 10 ⁰ C is maintained that one then stirred while maintaining this temperature for at least 20 minutes and that after neutralization with weaker stirring to a pH of about 6, the organic phase is separated at ^{-10 0} C from the aqueous phase.
The reaction proceeds according to the following equation: 2CH ₃ - (CH ₂ ) ₉ —CHCl-COCl + 2NaOH + H ₂ O ₂ * CH ₃ - (CH ₂ J ₉ - CHCl - C— O — O — C - - CHCl - (CH ₂ ) ₉ - CH ₃ + 2 NaCl + 2 H ₂ O 55 60 The α-chloro lauroyl peroxide has the advantage over the previously known α-chlorinated peroxides, that it is much more persistent and non-explosive in its pure state. While the previously known α-Chlorinated peroxides are characterized by the fact that they are extremely reactive and in a pure state are explosive, so that they can only be kept in solution at very low temperatures, this shows α-Chlorlauroylperoxid according to the invention has a very long aliphatic chain, which is used to stabilize the Molecule contributes and gives it better solubility. This makes it possible to be very focused To prepare solutions of α-chloro-lauroyl peroxide, the handling of which is harmless. It is with the aid of the method according to the invention possible, "" this a-chlorofluoroyl peroxide in essential produce higher yields than that with the previously known comparable process of α-peroxides the case is. In the process according to the invention, the specified process steps must carried out extremely carefully, as these are absolutely necessary to remove the chlorine substituent to hold in the α-position. If you do not adhere to the specified procedural requirements, there is a risk that in the very unstable a-chloro lauroyl chloride the chlorine substituent in the α-position in the oxidation reaction with the oxidizing agent participates, so that one decomposes products of a-Chlorlauroylchlorid in the form of their sodium salts in place of the desired a-Chlorlauroylperöxyds obtained. In the inventive method, in which the two at a temperature of - reagent held 10 ⁰ C within 20 minutes at - 10 ⁰ C are combined with one another with vigorous stirring and then, the stirring at - 10 ⁰ C is continued for at least 20 minutes, a very slow reaction of the reagents takes place, and this makes it possible to keep the chlorine substituent, as desired, in the α-position. Alpha-chloro lauroyl peroxide is particularly suitable as a supplier of active and free oxygen Radicals for all those cases in which this task occurs. The following examples illustrate the preparation of α-chloro lauroyl peroxide.