JPH0611362B2 - Formation and destruction of oil-in-water emulsion - Google Patents

Description

TECHNICAL FIELD The present invention aims to provide an O / W (oil-in-water) emulsion forming method and a breaking method.

That is, it is a technique of emulsifying in order to improve the contact efficiency of water with an organic solvent that is incompatible with water, and then breaking the emulsion to improve the separation of the organic solvent and water as needed.

Conventional technology Conventionally, suspending or emulsifying in order to increase the contact efficiency of water with an organic solvent that is not compatible with water is a process such as washing and removing unnecessary substances after the reaction, and is widely used industrially. Has been done. At that time, it is common to apply a large shear stress at the time of stirring with a homogenizer, a line mixer, a contactor or the like, or to use an organic surfactant as an auxiliary agent.

However, in that case, there are problems that a large amount of energy is required for stirring, it is difficult to remove the used surfactant, or a removing step is required.

In addition, after the contact between the organic solvent and water, oil-water separation operation is often performed in the next step, but at that time, it is necessary to use an antifoaming agent, an emulsion breaking agent, etc. It often took a long time to get there. Also,
At that time, it was naturally necessary to remove the defoaming agent.

Such surfactants and antifoaming agents often remain in the organic solvent layer, but when there are particularly useful ones in the organic solvent layer, the residual of such impurities in the layer is fatal. It was often a drawback.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks of the prior art.

Means for Solving Problems The present invention employs the following method as means for solving the above-mentioned drawbacks.

That is, an aqueous solution containing a trace amount of ions that form a weakly alkaline and hardly soluble colloidal precipitate and an organic solvent containing raw materials, reactants, catalysts, etc. are strongly agitated in a weak alkaline to form an O / W emulsion with a relatively short life. . After making contact with oil and water in this way, the pH of the emulsion is made strongly alkaline to eliminate the emulsion, and the oil and water separation operation is carried out quickly and satisfactorily.

Further, especially when making an O / W emulsion with a hydrocarbon solvent and water, if a trace amount of a higher alcohol coexists, the life of the emulsion increases. .

Action Each component of the present invention will be described below.

Ions for forming a sparingly soluble colloidal precipitate in the weak alkaline region used in the present invention are Periodic Tables Ib, II and II.
Group I, IV, Vb, VIb, VIIb, VIII and one or more divalent to hexavalent ions of lanthanides and actinides, such as Al (I
II), Ac (III), Ti (IV), Zr (IV), V (IV), V (V), Fe (I
I), Fe (III), Cu (II) and other ions may be used alone or in combination of two or more. Further, counter ions of these ions may include OH ⁻ , SO ₄ ²⁻ , Cl ⁻ , Br ⁻ , NO ₃ ⁻ , CO ₃ ^{2− and the} like. However, in any case, it is essential to use it under the condition that a poorly soluble hydrated colloid is produced.

The organic solvent used in the present invention is an aliphatic or aromatic hydrocarbon, an alkyl halide, a higher alcohol, a phenol, a ketone, an aldehyde, an ester, an amine, a nitrile, or the like, or a mixture thereof, and water. And n-heptane, 1-hexane, 1-hexene, liquid paraffin, benzene, toluene, styrene, indene, cumene, chloroform,
Examples include 1-octanol and phenol.

Further, these organic solvents may contain a polymer, an organic compound, an organometallic compound, and an inorganic compound which are soluble in the organic solvent.

The compounds used to control the pH in the present invention include commonly used inorganic acids, alkalis such as NaOH, KOH, H.
Examples include Cl and H ₂ SO ₄ .

Further, in the present invention, using hydrocarbon as an organic solvent O / W
When forming an emulsion, a higher alcohol (eg, 1-hexanol, 2-methyl-2-pentanol, ethylphenylcarbinol, stearyl alcohol) is added to the oil layer in an extremely small amount (0.1 to 100 w / vppm). Then, the emulsion may be significantly stabilized.

The conditions for the O / W emulsion production operation of the present invention are as follows.

(1) Temperature: usually 0 to 300 ° C., preferably room temperature to 200 ° C. (2) Pressure: usually 0 to 1000 kgf / cm ² , preferably atmospheric pressure to 10
0 kgf / cm ² (3) Strong stirring time (batch type): usually 10 sec to 10 hr, preferably 10 sec to 1 hr.

Strong stirring time (continuous type, residence time): Usually 0.1sec-10h
r, preferably 1 sec to 1 hr.

(4) Amount ratio of organic solvent and water in the system: batch type, continuous type, 1: 1000 to 1000: 1, preferably 1: 100 to 1
00: 1 (volume ratio) (5) The pH of the water side in the system is 7 to 11, preferably 9 to 10 (6) The ion concentration for forming the colloidal precipitate on the water side in the system is 0.001 to 1000 w relative to water. / vppm (weight / volume ppm = 1
(mg / 1 solvent), preferably 0.1 to 100 w / vppm (7) Stirring is not particularly specified, such as an ordinary winged one or a homogenizer.

(8) When the organic solvent contains a polymer that is soluble in it, the solution viscosity is 0.1 to 10,000 cp, preferably 0.1 to 100.
It is 0 cp.

(9) When a hydrocarbon is used as the organic solvent, the amount of higher alcohol added to stabilize the emulsion by adding a trace amount is 0.01 to 1000 w / vppm, preferably 0.1 to 10 w relative to the organic solvent.
It is 0w / vppm.

Also, a pH that improves oil-water separation by breaking the emulsion.
The conditions are pH 11 or higher, preferably pH 11.5 or higher.

Hereinafter, description will be made with reference to examples.

Example of generation of short-life O / W emulsion A. Effects of Various Ions Examples 1 to 9 1-In a glass autoclave, 300 ml of water containing a predetermined concentration of inorganic ions and adjusted to a predetermined pH, and 300 ml of liquid paraffin are placed. Minimum amount of NaO required for pH adjustment
H or HCl was used. Next, the temperature is raised to a predetermined temperature while stirring at about 100 rpm. 1000 rpm while keeping the temperature constant
After stirring for 10 minutes, stop and measure the time required for oil-water separation and the amount of residual emulsion. The criteria for judgment of separation are as follows.

(1) When oil water separates in a relatively short time (within 20 minutes) and the emulsion layer also disappears.

Time → Time required for the water layer to recover to approximately 300 ml Minute amount of emulsion → Emulsion amount when the water layer was recovered to approximately 300 ml (2) Most of oil / water was separated in a relatively short time (5 to 20 minutes) However, if it takes time for the emulsion to disappear.

Time → 240ml or more (about 80%) Time when the water layer was recovered (however, the emulsion hardly decreased in 1 minute after that) Emulsion amount → Emulsion amount at the above time (3) Oil-water separation was slow (it took 20 minutes or more) ) If.

Time → 20 minutes or more Emulsion amount → Amount 20 minutes after stopping stirring The results of oil-water separation experiment using this method were as shown in Table 1.

Comparative Example 1 The same operation as in Examples 1 to 9 was carried out except that no inorganic ion was added to the aqueous layer, and the results shown in Table 1 were obtained.

B. Effect of various organic solvents Examples 10 to 14 Isohexane or ethylene propylene rubber (M
FR (230 ℃) = 1g / 10min) in isohexane (50g /
) Was used, and the same operation as in Examples 1 to 9 was carried out except that 1-homogenizer was used instead of 1-autoclave, and the results shown in Table 2 were obtained.

Comparative Examples 2 to 3 The same operation as in Examples 10 to 14 was carried out except that Fe ³⁺ ions were not added to the aqueous layer, and the results shown in Table 2 were obtained.

Example 15 Acetone and phenol (1: 1 wt ratio) in the oil layer and 20 in the water layer
The same operation as in Examples 1 to 9 was carried out except that a wt% Na ₂ SO ₄ aqueous solution was used, and the results shown in Table 3 were obtained.

Comparative Example 4 The same operation as in Example 15 was carried out except that Fe ³⁺ ions were not added to the aqueous layer, and the results shown in Table 3 were obtained.

C. Combined effect of higher alcohols Examples 16 to 18 The same operation as in Examples 1 to 14 was carried out except that the higher alcohol was added to the oil layer, and the results shown in Table 4 were obtained.

Comparative Examples 5 to 8 The same operation as in Examples 16 to 18 was carried out except that Fe ³⁺ ion or higher alcohol was not added, and the results shown in Table 4 were obtained.

D. Example of destruction of short-life O / W emulsion by pH adjustment Examples 19 to 24 When the pH adjustment was made strongly alkaline by the same operation as in Examples 1 to 18, the emulsion was destroyed as shown in Table 5.

Comparative Examples 9 to 14 When the pH was adjusted to around 9.5 in the same manner as in Examples 19 to 27, the results shown in Table 5 were obtained.

Examples 25 to 26 After the operations of Comparative Examples 9 and 12, NaOH was added, the mixture was stirred again and allowed to stand, and the results shown in Table 5 were obtained.

EFFECTS OF THE INVENTION According to the present invention, it is extremely easy to remove unnecessary substances by temporarily emulsifying an organic solvent that is not compatible with water, which is often generated in various industries, and then breaking and separating oil and water. Became.

Claims (2)

[Claims] 1. An aqueous solution containing a trace amount of ions that form a weakly alkaline and sparingly soluble colloidal precipitate and an organic solution that is incompatible with water are strongly agitated in a weak alkaline manner to form an oil-in-water emulsion, A method of rapidly and satisfactorily separating oil and water by making the pH of the emulsion strongly alkaline and destroying the emulsion. 2. The method according to claim 1, wherein the pH when the emulsion is formed is 7 to 11 and the pH when the emulsion is broken is 11.5 or more.