DE4002472A1 - METHOD FOR CLEAVING OIL / WATER EMULSIONS - Google Patents

Abstract

The invention concerns a process for separating oil-water emulsions using organic emulsion separators. These are obtained by the reaction of primary, secondary and/or tertiary alkyl amines with propylene oxide and/or ethylene oxide in the presence of inorganic and/or organic acids. The compounds thus obtained, of the general formula (I), are used in concentrations of 0,01 to 10 vol. % to separate oil-water emulsions.

Description

The invention relates to a method for splitting oil / water Emulsions using organic emulsion splitters.

Very often when processing metallic materials Coming oil-in-water emulsions (O / W emulsions), such as for example cooling lubricant, deep drawing, cutting or drilling emulsions, the oil phase of which is predominantly natural or synthetic table oils of different chemical composition and Her future exists, are not subject to only one in their application Wear, but are also caused by the entry of foreign substances contaminated. They must therefore be disposed of regularly. The most important step in the - possibly continuously ablau fenden - disposal consists in splitting the processed Emulsions; this means that the oil phase as far as possible from the water phase must be separated to either the separated To be able to process and reuse the oil phase or to do this and the also separated water phase is ecologically harmless to be able to dispose of normal disposal methods.

O / W emulsions also fall significantly in the Ge oil extraction and production. This is O / W emulsions, which are often stabilized by fine clay particles are based. O / W emulsions also fall in the petroleum sector  transportes and further processing in the refinery area. All these emulsions have in common that they are for disposal or Further use of the water phase and for further processing of the Oil phase must be split.

The majority of all emulsions are either natural or due to of special formulations with anionic surfactants stabili siert. Accordingly, the gap used in practice medium consistently of a cationic charge character, d. i.e., correspond Chen cationic surfactants. Emul corresponds to the state of the art Sion splitter of the cationic type based on copolymers from dimethylamine and epichlorohydrin or other comparable Polyamines. The influences that affect the effectiveness of a cationic Making surfactants suitable as emulsion breakers are not known. However, it has been shown in the past that it is only relatively narrow limited classes of cationic surfactants are suitable for cleavage are. So are classic quaternary ammonium compounds, e.g. B. Cetyltrimethylammonium chloride is absolutely unsuitable as a splitting agent.

The former cleavage of such emulsions by mineral salts or acids was due to the ecological disadvantages and the high amount of splitter required for complete cleavage cessive replaced by splitting processes in which to the emulsion gap organic splitter, usually surface-active substances, be used. Their advantage can be seen in the fact that for a complete split necessary concentrations of use low, for example in the range of 0.01 to 10% of the emulsi quantity, and the splitters dispose of the oil phase for example when burning, do not affect. Furthermore they do not lead to any noteworthy contamination of the aqueous substances Phase.  

A complete emulsion breakdown is only in a relatively narrow Range of dosing of the splitting substances possible. Below in this area, the emulsion splitting is incomplete, which is noticeable in an undesirably high oil content in the water phase makes; the overdose of the spal leads above this range ters and the associated re-emulsification also into one Increase in the oil content in the water phase, which is natural is also undesirable. An additional difficulty is in it to see that the oil-in-water emulsions obtained in practice with regard to composition, concentration of components, pH Value, temperature and other parameters fluctuate greatly may be subject. These disadvantages lead to the fact that practical use of surfactants as Emulsion splitter constant empirical reviews of the gap telart and the amount of splitting agent are necessary for each type the optimal dosing range for the organic To determine splitter.

In practice, the optimal dosing range is usually determined by visual observation of the course of the gap in the emulsion splitting determined. This determination of the optimal dosing range for the Splitter, d. H. the end point for the addition of ver as a splitter applied surfactant compound, is usually like this taken that a splitter was added until a flo forming oil / mud flakes. To avoid overdoses, this must be done with the addition of small amounts of splitter, which is why the Splitting of oil / water emulsions with visual determination of the end takes a period of several hours.

As splitters (demulsifiers) are preferred in the prior art cationic polymers for use. These usually indicate Molecular weight in the range of 50,000 to 500,000. In the  Even at low demulsifier concentrations, Verbin based on polyamines, polyamide amines, polyimines, Condensation products from o-toluidine and formaldehyde, quaternary Ammonium compounds and ionic surfactants are used. Of these are polyamines with an average molecular weight in the range of 75,000 to 200,000 or condensation products from o-toluidine and Formaldehyde due to the good splitting results even at low ones Splitter concentrations are particularly preferred.

Quaternary ammonium salts are known from EP-PS 00 98 802, which be made from tertiary amines and ethylene oxide. These are particularly suitable for use in hair cosmetics, such as Hair conditioners.

From the European patent specification 2 13 601 corresponding Ver known compounds consisting of tertiary amines and ethylene oxide and / or propylene oxide.

It has now surprisingly been found that certain reaction products of amines and alkylene oxides or their salts excellent as Emulsion splitter suitable for cleaving the above-mentioned emulsions are not. This is by implementing primary, se secondary or tertiary amines with propylene oxide and / or ethylene oxide Quaternary ammonium bases obtained. Process for the preparation of the substances mentioned are in European patent specifications 00 98 802 and 02 13 601.

The invention thus relates to a process for splitting oil / Water emulsions, which is characterized in that Compounds of the general formula (I) are used:  

in which

R represents a straight-chain or branched-chain alkyl radical having 12 to 18 carbon atoms,
R¹ and R² each independently represent an alkyl radical with 1 to 4 carbon atoms or a hydroxyalkyl radical with 1 to 4 carbon atoms,
R³ represents H or CH₃,
n for an integer ranging from 1 to 6 and
X stands for an anion which is selected from the acids hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid or nitric acid or low molecular weight organic mono-, di- or tricarboxylic acids,

with the proviso that the ratio of R³ = CH₃ to R³ = H at least Is 3: 1.

The connections to be used are per se in the state of the Technique known by implementation of primary, sekun där or tertiary amines with ethylene oxide and / or propylene oxide obtained in the presence of the desired acid. Appropriate procedures are particularly from the European patent specification 00 98 802 and the European patent specification 02 13 601 known.

Primary, secondary or tertiary alkylamines in which the radicals R ¹ and R ^{2 are} identical are particularly preferred as starting materials. Accordingly, a particular embodiment of the vorlie invention is that one starts from dimethylalkylamines in the preparation of the compounds to be used according to the Invention.

For the purposes of the invention, compounds of the formula (I) in which R ¹ and R ^{2 are} a methyl radical are therefore used.

The aforementioned amines can either be mixed directly with ethylene oxide and / or propylene oxide are implemented or according to known Processes as random or block polymers of ethylene oxide and Propylene oxide can be obtained. This is also about processes known in the art.

Compounds to be used according to the invention in which the ratio of R ³ = CH ³ to R ³ = H is less than 3: 1 are too hydrophilic for the splitting of oil / water emulsions, so that they are less suitable for the present invention are. Accordingly, it is preferred to use the largest possible ratio of propylene oxide to ethylene oxide units. It is therefore particularly preferred that the radical R ^{3 is} exclusively CH₃, that is to say the compounds to be used according to the invention are propoxylates of quaternary ammonium compounds.

In a further preferred embodiment of the present Er Invention will be the number of propylene oxide and / or ethylene oxide units set so that only one or two of these one units are present in the molecule. Accordingly, n stands for 1 or 2.

As stated in EP-PS 00 98 802, in particular in Example 1, the alkylamines with an inorganic acid or low molecular weight organic mono-, di- or tricarboxylic acid new tralized and heated. Then ethylene oxide and / or Propylene oxide passed through the reaction mixture.  

In a preferred embodiment of the present invention are the mono-, di- or tricarboxylic acids selected from ants acid, acetic acid, propionic acid, glycolic acid, lactic acid, oxalic acid re, malonic acid, succinic acid, glutaric acid, adipic acid, malein acid, fumaric acid, malic acid, tartaric acid, citric acid and / or Aconitic acid. According to the invention, the one are of particular importance adding lactic acid salts, d. H. the lactates.

The emulsions to be split by the process according to the invention are without exception oil-in-water emulsions, such as those when processing metallic materials. These Emulsions are used to cool workpieces and tools at metal cutting, for example when cutting, Drilling and turning, or to improve the sliding and separating ver holding in non-cutting metal processing, for example in Deep drawing. Emulsions in this sense are processed or for experimental purposes also synthetically produced coolant, Deep-drawing, cutting and / or drilling emulsions, including emulsions mixtures fall under the term mentioned. With the described Oil-in-water emulsions are aqueous systems that are up to may contain up to 10% foreign oil: under emulsions in the above However, the above-mentioned sense will also make the classic alkaline, new understood or acidic degreasing and cleaning baths that for example in the automotive industry for degreasing or Cleaning of metal sheets.

The amounts of the compounds of the general formula to be used (I) for splitting oil / water emulsions are less critical. Especially when performing the method according to the automa table control according to DE-OS 36 27 199 results in concentration to be used automatically from the process.  

Preferred in the sense of the present invention, in particular in the Hin looking at the entry of substances into the environment is a con concentration of the connections to be used according to the invention of 0.01 up to 10 vol .-%, based on the emulsion to be split.

In this sense, the implementation of the Process for splitting oil / water emulsions, wherein the Compounds of the general formula (I) in a concentration of 0.05 to 2 vol .-%, based on the emulsion to be split, is used.

In principle, the method according to the invention can be used in any Temperature range are carried out in which a thorough mixing of the compounds of the general formula (I) with the oil / water Emulsion is possible. Thus, the cleavage of the invention Emulsion between the pour point of the emulsion and the boiling point be performed. Preferred in the sense of the present invention is the implementation of the process in the range between room temperature and 80 ° C.

Particularly good results are obtained if the control of the Cleavage according to the method according to DE-OS 36 27 199 au is carried out automatically.

When splitting both fresher, i.e. for experimental purposes prepared oil / water emulsions as well as in practice Lender processed oil / water emulsion occurs when adding of an organic splitter an increase in the haze of the emulsion on. The increase in turbidity is due to the fact that in the split water phase aggregates between the organic anions of the Emulsifier and the preferably cationic polymer ions of the Form splitter or demulsifier. With further addition of orga niche splitting agents, the turbidity rapidly decreases. This is based  no longer coalescing in the aqueous phase emulsified oil droplets and the associated decrease in Ge total number of oil particles.

In a preferred embodiment of the method according to the invention rens is the ratio of the two measurement signals of two De tectors according to DE-OS 36 27 199 calculated result used to add organic splitter automatically too interrupt. This happens according to the invention when the Trü Exercise based on the formation of aggregates between emulsifier anion and demulsifier cation, based on the decrease in turbidity is stored by coalescing those that are no longer emulsified Oil droplet is caused. As a result of the overlay of Trü In practice, increasing and decreasing turbidity results in cloudy conditions exercise maximum, which with further addition of organic splitter first turbidity minimum follows. This minimum turbidity results in that the decrease in turbidity in the emulsion by a new Increase in turbidity is superimposed, which results from the fact that the coalesced oil droplets can be re-emulsified, consequently the number of particles and thus the measured turbidity increased. There re-emulsification of the oil droplets is not required Adding the organic splitter before the start of the re-emulsification, d. H. interrupted at the first minimum of the turbidity curve. The gap added at the time of the measured turbidity minimum The quantity corresponds exactly to that for a complete splitting of the Emulsion required amount of organic splitter because exactly at this point the amount of cleavage added that was originally in the Emulsion corresponds to the amount of emulsifier present and thus an approx complete separation of the emulsion can be achieved.

As stated above, either the ratio of from through Light and stray light received measurement signals directly to it  are used, the addition of organic cleavage then to under break when the turbidity after the maximum he first minimum was enough.

However, it is also in another embodiment of the invention possible to reduce the amount of organic splitter manually break when the one written down with the help of a pen Curve that shows the turbidity curve depending on the added The amount of splitter represents a first mini after the turbidity maximum mum reached.

The invention is illustrated by the following examples tert.

As a guideline for the result of the emulsion splitting achieved served the residual oil content in the split water phase. According to DIN 38 409 H 17 / H 18 became the petrol extra contained in the split water phase heritable substances (PE) determined. The experimental setup was the the following:

A 1-liter beaker was filled with 600 ml each Emulsion filled and continuously using a magnetic stirrer stirred at 500 rpm. The length of the stir bar was 50 mm.

An immersion concentre served as a measuring device for measuring the turbidity tration knife, model 25/34, from Monitek.

The sensor, type 25 (immersion probe), was on a tripod attached. The immersion depth of the probe was adjusted, i. H. all Measurements were carried out at the same immersion depth of the immersion probe taken.  

The opacimeter was with a pen to take the measurement values (turbidity versus added amount of splitter). At con The constant stirring speed of the magnetic stirrer was the respective organic splitters drop by drop at predetermined time intervals or added in a continuous, slow flow.

From the untreated, i.e. not yet split emulsion as well samples were taken to check the individual fissure water phases taken. In the split water phases, after 30 min time the petroleum ether-soluble fractions (PE) according to the above specified DIN regulation.  

example 1

A mineral oil-containing, water-miscible coolant emulsion P-3 multan 94 from the collection container of an automobile factory, which in the essential mineral oil, corrosion inhibitor, wetting agent, anionic and contains nonionic surfactants has been described with the above Experimental setup split. A connection of the general formula

with R = C _12/18 alkyl used.

The oil / water emulsion cleavage data obtained are See table 1.

Comparative Example 1

In the same way as in Example 1, a mineral oil-containing water-miscible coolant emulsion with an organic Split splitter.

A copolymer of dimethylamine and epichlorohydrin was used a molecular weight of 0.15 × 10⁶ used, as under the Name "Ferolin® 8686" is available from the applicant.

The results obtained are shown in Table 1.  

Comparative Example 2

According to Example 1, a mineral oil-containing, water-miscible coolant emulsion was split using the test arrangement described above. A copolymer of dimethylamine and epichlorohydrin with a molecular weight of 0.5 × 10 ^{6 was} used as the splitter, which is manufactured by the applicant under the name "Ferolin® 18687".

The results obtained are shown in Table 1.

Table 1

So the split water quality is when using this splitter have been significantly improved, the oil phase is less water than in the Comparison.

Example 2

The comparative measurement of the mean against two in the market Organic splitter based on polyamine currently used  was carried out on freshly prepared emulsions commercially available cooling mineral oil-based lubricants. It should be mentioned that fresh Emulsions are generally more difficult to split than processed killed. The cleavage was carried out on samples of 1 l volume at room temperature temperature. The dosing end point was determined automatically in accordance with DE-OS 36 27 199.  

Table 2

The cleavage with the agent according to the invention thus leads to a Splitting water phase with very low mineral oil contents, which is the pre of waste water limit values.

Claims (10)

1. Process for the cleavage of oil / water emulsions, characterized in that compounds of the general formula (I) are used: in which
R represents a straight-chain or branched-chain alkyl radical having 12 to 18 carbon atoms,
R ¹ and R ² each independently represent an alkyl radical with 1 to 4 carbon atoms or a hydroxyalkyl radical with 1 to 4 carbon atoms,
R ^{3 represents} H or CH ₃ ,
n for an integer ranging from 1 to 6 and
X represents an anion which is selected from the acids hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid or nitric acid or low molecular weight organic mono-, di- or tricarboxylic acids,
with the proviso that the ratio of R ³ = CH ₃ to R ³ = H is at least 3: 1. 2. The method according to claim 1, characterized in that R ¹ and R ^{2 are the} same. 3. The method according to claim 2, characterized in that R ¹ and R ^{2 are} CH ₃ . 4. The method according to claims 1 to 3, characterized in that the grouping R ³ for a random or block polymer
- (CH₂-CH-O) _n
sat from ethylene oxide and propylene oxide. 5. Process according to Claims 1 to 4, characterized in that R ^{3 stands} exclusively for CH₃. 6. The method according to claims 1 to 5, characterized in that n stands for 1 or 2. 7. The method according to claims 1 to 6, characterized in that X for an anion from the low molecular weight organic mono-, di- or tricarboxylic acids which are selected from formic acid, Acetic acid, propionic acid, glycolic acid, lactic acid, oxalic acid, Ma lonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, Fumaric acid, malic acid, tartaric acid, citric acid and / or Aconitic acid. 8. The method according to claims 1 to 7, characterized in that the compounds of the general formula (I) in one conc tration of 0.01 to 10 vol .-%, based on the emul to be cleaved sion, begins. 9. The method according to claim 8, characterized in that the Compounds of the general formula (I) in a concentration of 0.05 to 2 vol .-%, based on the emulsion to be split, is used. 10. The method according to claims 1 to 9, characterized in that the cleavage of the emulsions in the range between room temperature and 80 ° C.