DE2811779A1 - Stabilised per:chloroethylene contg. cyclohexene oxide - N-alkyl morpholine, alkyl phenol and di:isopropylamine - Google Patents

Abstract

Stabilised perchloroethylene (I) contains (wt.%) (i) 0.001-0.01% >=1 N-alkylmorpholine (I) (alkyl is 1-5C, opt. branched) opt. ring substd. by 1-4C alkyl gps.; (ii) 0.001-0.01% >=1 1-18C opt. branched alkylphenol (II) (alkyl in ortho and/or para positions); (iii) 0.0005-0.002% diisopropylamine (iv) and (iv) 0.05-0.5 wt.% cyclohexene oxide (v). Esp. (II) and (III) are both 0.004-0.008 wt.%; (iv) 0.0008-0.0015 wt.% and (v) 0.1-0.3 wt.%. Specified additives are N-(m)ethylmorpholine and p-tert.butylphenol (IIIa). (v) gives synergistic enhancement of stability with respect to development of acidity and corrosion properties.

Description

Stabilized perchlorethylene

Stabilized perchlorethylene is known. In DE-OS 24 49 667 the addition of N-alkylmorpholine and alkylphenol is recommended for stabilization. From US Pat. No. 3,133,885 it is known to stabilize amines and To use oxiranes. Stabilized perchlorethylene according to DE-OS 24 49 667 is capable does not meet the increased requirements of technology with regard to the acid absorption capacity to meet more, such, stabilized according to US Pat. No. 3,133,885, fulfilled in terms of the corrosive properties of the technical requirements are only unsatisfactory Way. Finally, stabilized perchlorethylene, the phenols, is also known and oxiranes combined, it being possible for aniline or pyroles to be present at the same time. To stabilize against oxidative influences, however, aniline or pyrrole must be in comparatively large amounts are used.

It is a task to meet the increased requirements the invention to specify stabilized perchlorethylene, the acid absorption capacity and corrosion behavior as well as stabilizing effect of previously stabilized perchlorethylene is superior.

The invention is stabilized perchlorethylene, which thereby is characterized in that it is Ob001 to 0.01 wt.% N-alkylmorpholine with straight or branched alkyl chains with 1 to 5 carbon atoms and possibly

Carries alkyl substituents with up to 4 carbon atoms on the ring, as well as their mixtures 0.001 to 0.01 wt.% Alkylphenols with straight or branched alkyl chain with 1 to 18 carbon atoms in o- and / or p-position and their mixtures 0.0005 to 0.002% by weight of diisopropylamine and 0.05 to 0.5% by weight Contains cyclohexene oxide.

A preferred embodiment of the stabilized perchlorethylene is characterized in that the N-alkylmorpholines according to the invention in quantities between 0.004 and 0.008% by weight, the alkylphenols according to the invention in amounts of 0.004 to 0.008% by weight, the diisopropylamine mentioned according to the invention in amounts of 0.08 to 0.0015% by weight and the cyclohexene oxide mentioned according to the invention in amounts from 0.1 to 0.3 wt.% Are included.

Among the N-alkylmorpholines mentioned according to the invention are N-methyl- or To designate N-ethylmorpholine as particularly preferred, among those according to the invention The alkylphenols mentioned are particularly distinguished by p.-tert.-butylphenol the end.

Surprisingly, it was possible to use a combination of known stabilizing agents Components to achieve a synergistically increased stabilization. This is all the more surprising as it was known from DE-OS 24 49 667 and DRP 573 105, that the stabilizing effect of alkylphenols and N-methylmorpholine through the Addition of diisopropylamine is greatly weakened. By using additional cyclohexene oxide, however, the stabilizing effect, in particular against corrosive attack, not weakened, but on the contrary significantly increased.

This effect is satisfactory only from cyclohexene oxide Fulfills.

Stabilized perchlorethylene should already be used at a low level stabilizing components have a long-lasting stabilizing effect on perchlorethylene against oxidative decomposition on contact with metals, alloys, metal salts, Have cutting oils and exposure to light and thermal stress and beyond the perchlorethylene a long-lasting increased acid absorption capacity to lend.

In particular, the stability towards metals such as iron, copper, Zinc and aluminum will be good and corrosion on these metals will be prevented.

The stabilizer components are in dissolved form in the perchlorethylene contain.

According to the invention, N-alkylmorpholine is branched morpholine or straight alkyl chains with 1 to 5 carbon atoms understood, furthermore can the ring in the 2-, 3-, 5- or 6-position with alkyl chains with up to 4 carbon atoms be substituted. N-methyl- or N-ethylmorpholine is preferably used.

Alkylphenols include o- and / or p-alkylphenols with 1 to 18 Understood carbon atoms with straight or branched alkyl chain.

Alkylphenols containing 2 to 8 carbon atoms are preferably used have in the alkyl chain, in particular those alkylphenols that have a branched Have alkyl chains with 3 to 5 carbon atoms in the p-position, also in a mixture, used.

Particularly good stabilization is obtained with a mixture of N-methylmorpholine, p-tert-butylphenol, diisopropylamine and cyclohexene oxide.

The stabilizer effectiveness against oxidative influences is determined by studies determined according to the conditions of the MIL test 7003.

For this purpose, 200 ml of perchlorethylene are poured through from below in a test flask a frosted 150 watt incandescent lamp is heated and exposed. The boiling perchlorethylene comes with a steel strip of 12.7mm x 50.8mm x 1.59mm, which comes with a VA wire is suspended in a reflux condenser placed on the flask, in contact. A second steel strip, 6.35 mm x 19.5 mm x 1.59 mm, is placed on the piston crown placed in the boiling liquid. Through a 3 mm diameter glass tube that Ends 6.35 mm above the piston crown, a stream of oxygen saturated with water is generated introduced into the perchlorethylene from 10 to 12 bubbles / minute. From the cooled down A sample is taken from the contents of the flask and titrated in the aqueous extract 0.1 N sodium hydroxide solution against phenolphthalein determines the acidity. Rehearse, whose acidity exceeds 0.02% by weight after the 48-hour test, 'hydrochloric acid, are ineffective stabilized. The measure of the stabilization effect is time until the acidity limit of 0.02% hydrochloric acid in the perchlorethylene is reached, expressed in hours. The acid absorption capacity of stabilized perchlorethylene is determined as follows: 25 cm3 of hydrochlorination solution (prepared from 1 cm3 of concentrated Hydrochloric acid and 250 cm3 of methanol) are mixed with 25 cm3 of distilled water in a Erlenmeyer flask filled and with 0.1 N sodium hydroxide solution against phenolphthalein up to permanent pink color titrated (consumption A in ml). Then 25 cm³ of the hydrochlorination reagent and 15 cc sample is pipetted into a flask and refluxed for 5 minutes. To Cool, 25 cm3 of distilled water are added and 0.1 N sodium hydroxide solution titrated (consumption B'in ml). The acid absorption capacity is calculated as (A - B) x 0.4 =% by weight sodium hydroxide solution V x D V = volume of the sample in cm3 D = density of the sample in g / cm3 The stabilizer effectiveness against corrosion is determined by simple tests demonstrated, taking samples of metal strips made of iron, copper, aluminum, zinc, which are partially immersed in the liquid phase, with perchlorethylene 168 hours on To be refluxed. The extent of discoloration or tar formation on the metal surface after the end of the test is a measure of the corrosive properties of the stabilized perchlorethylene.

The following examples, which are summarized in Table 1, clearly show the superiority of the stabilization according to the invention.

Table I Hours to Corrosion to Achieve SAF behavior % NaOH versus acidity - after 72 h Fe, Cu, No. ppm stabilizer limit reflux *) Zn, Al 1 15 diisopropylamine strong Kor-50 N-methylmorpholine 100 0.01 rosion Cu, 30 p.-tert.-butylphenol Zn 2 50 N-methylmorpholine light corro-30 p.-tert.-butylphenol 145 0.01 ion Fe, Cu, Zn 3 50 N-methylmorpholine 180 p.-tert-butylphenol bo 0.06 Corrosion Fe, 30 p. -tert-butylphenol Zn 2 500 cyclohexene oxide 4 15 diisopropylamine slight corrosion 30 p.-tert.-butylphenol 70 Q, 06 sion against 2,500 cyclohexene oxide Fe, Cu, Al 5 15 diisopropylamine no corrosion 50 N-liethylmorpholine against sion against 30 p-tert-butylphenol 3 0.07 Fe, Cu, Al, Zn 2 500 cyclohexene oxide 6 15 Diisopropylamine slight, slight corrosion on Fe, Zn, 175 0.04 sion on Fe, Zn, 30 p.-tert.-butylphenol Cu 2 500 propylene oxide 7 15 diisopropylamine 50 N-methylmorpholine corrosion on 30 p.-tert.-butylphenol 180 0.05 Fe, Cu, Zn 2 500 butylene oxide *) followed by ten distillation SAF = acid absorption capacity hours until corrosion is achieved 72 h Fe, Cu, No. ppm stabilizer limit reflux *) Zn, Al 8 15 diisopropylamine 30 N-methylmorpholine light corrosion 30 p.-tert.-butylphenol 190 0.06 sion on Fe, Zn 2 500 epichlorohydrin 9 - 15 aniline 50 N-methylmorpholine strong corrosive 30 p.-tert.-butylphenol. 170 0.06 sion of Cu, Fe, Zn 2,500 cyclohexene oxide

Claims (3)

P a t e n t a n s p r ü c h e 1. Stabilized perchlorethylene, i a d u r c h g e k e n n n -z e i c h n e t that there is 0.001 to 0.01% by weight of N-alkylmorpholine with straight or branched alkyl chains with 1 to 5 carbon atoms and possibly Carries alkyl substituents with up to 4 carbon atoms on the ring, as well as mixtures thereof, 0.001 to 0.01% by weight of alkylphenols with straight or branched alkyl chain with 1 up to 18 carbon atoms in o- and / or p-position, and mixtures thereof 0.0005 up to 0.002% by weight diisopropylamine and; Contains 0.05 to 0.5% by weight of cyclohexene oxide. 2. Stabilized perchlorethylene, d u r c h e k e n n -z e I c h e t that there is 0.004 to 0.008 wt.% N-alkylmorpholine with straight or branched Alkyl chain with 1 to 5 carbon atoms and optionally alkyl substituents with up to 4 carbon atoms on the ring, and mixtures thereof, 0.004 to 0.008% by weight of alkylphenols with straight or branched alkyl chain with 1 to 18 carbon atoms in o- and / or p-position, and mixtures thereof and 0.0008 to 0.0015% by weight of diisopropylamine and Contains 0.1 to 0.3% by weight of cyclohexene oxide. 3. Stabilized perchlorethylene according to claim 1 to 2, d a d u r It is noted that N-Alkymorljholin, N-Methyl- or N-Ethylmorpholin and the alkylphenol is p-tert-butylphenol.