JPS6056134B2 - Separation method for aminoalkyl acid sulfate esters - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating and recovering aminoalkyl acidic sulfuric esters that are produced by being cloudy in a solvent.

The method for producing amino alcohol sulfate esters is already known.

That is, it is a method in which an amino alcohol and sulfuric acid are heated and dehydrated in the presence of a suspending solvent, and the produced water is removed by azeotropic distillation to obtain an amino alcohol sulfate ester.

However, the amino alcohol sulfate ester produced by this method is generally separated using a centrifuge or filtration device and then dried, or when the amount of solvent is small, it is dried directly in a spray dryer. There is.

However, this method has the disadvantage that not only the process and equipment become complicated, but also additional costs are required to prevent loss of solvent due to drying. The present inventors have conducted extensive research to overcome this drawback in separating aminoalcohol sulfuric esters, and as a result, we have added a 10 to 35% by weight aqueous solution of alkali hydroxide to aminoalcohol sulfuric esters suspended in a solvent. It was discovered that if a predetermined amount is added, it will separate into two phases: a solvent phase and an aqueous solution phase in which a salt of aminoalcohol sulfate is dissolved, and that the above objective can be achieved by separating the aqueous solution phase, and based on this knowledge. The present invention was made based on this.

That is, the present invention provides a compound represented by the general formula R')-R-(CH2)n0H R''' (wherein R is hydrogen or a lower alkyl group). R'' and R'' are hydrogen or a lower alkyl group, and n is an integer of 1 to 3.

) and sulfuric acid or the acidic sulfate of the alkanolamine are heated and dehydrated in a suspending solvent, the resulting water is removed by azeotropic distillation, and then a 10 to 35% by weight aqueous solution of alkali hydroxide is prepared. A method for separating an aminoalkyl acidic sulfuric ester from a suspending solvent, the method comprising: adding a suspended aminoalkyl acidic sulfuric ester to the suspended aminoalkyl acidic sulfuric ester, and separating an aqueous alkali hydroxide phase in which the sulfuric ester is dissolved. This is what we provide.

The concentration of the aqueous alkali hydroxide solution used in the present invention is usually 10 to 35% by weight, preferably 20 to 2% by weight, and more preferably about 25% by weight.

The aminoalkyl acidic sulfate ester has a maximum solubility peak at about 25% by weight in the above concentration range of alkali hydroxide. This unique relationship is illustrated in the drawing. 1 in the diagram
is a graph at 30°C, and 2 is a graph at 500C. In the present invention, when the concentration of the aqueous alkali hydroxide solution is less than 1% by weight, the solubility of the aminoalkyl acidic sulfate ester is low and the concentration is low, so that the amount of the aqueous alkali hydroxide solution required for extraction increases. Therefore, not only the container for dissolution but also the reactor container when the aminoalkyl acidic sulfuric ester is used as a raw material for producing ethyleneimines or mercaptothiazolines becomes larger than necessary, making it difficult to carry out industrially. There isn't. Also, the concentration of aqueous alkali hydroxide solution is 3
If it exceeds 5% by weight, the solubility of the aminoalkyl acidic sulfuric acid ester decreases rapidly and is therefore unsuitable for carrying out the present invention. In the present invention, the aqueous alkali hydroxide solution is used in such a manner that the amount of the alkali hydroxide is equal to or more than twice the mole of the aminoalkyl acidic sulfuric ester. As aqueous alkali hydroxide solutions, NaOH, KOH
, LiOH, RbOH, CsOH are preferred, but these may also be prepared from the corresponding oxides of alkali hydroxides.

In the present invention, the dissolution and extraction of the aminoalkyl acidic sulfuric ester with this aqueous alkali hydroxide solution is usually carried out at 50° C. or lower so as not to cause hydrolysis of the sulfuric ester.

In the method of the present invention, known conditions for preparing aminoalkyl acidic sulfuric esters from aminoalkanol and sulfuric acid can be applied to the reaction conditions, reaction component ratios, etc. not mentioned above.

Specific examples of the alkanolamine include 2-aminoethanol, 2-amino-1-propanol, 2-methyl-aminoethanol, 3-amino-1-propanol, and 2-aminobenzyl alcohol.

Moreover, as the sulfuric acid, concentrated sulfuric acid, fuming sulfuric acid, etc. are preferably used.

Further, as a suspending solvent, one that is inert to the reactants and reaction products is used. Examples include hydrogen, carbon tetrachloride, halogenated hydrocarbons such as peroxyethylene, and mixtures thereof.

These solvents preferably have a boiling point in the range of 100 to 150°C under normal pressure. According to the method of the present invention, aminoalkyl acid sulfate esters suspended in a solvent can be easily and efficiently separated and recovered without using complicated equipment such as a centrifuge, which is extremely advantageous industrially. .

Next, the present invention will be explained in more detail based on examples. Example 1 500 mt of xylene and 61 mt of monoethanolamine were placed in a reactor equipped with a stirrer, temperature control means, condenser and dropping funnel.
g and 10% sulfuric acid while cooling to below 60℃.
0 g was dropped.

After adding dropwise sulfuric acid, the temperature was raised and distillation of xylene was started. The distillation rate was set at 160 m1/H to ensure that the dehydration reaction progressed sufficiently.
It took me 3 hours on r. The distillate obtained at this time was separated by standing, and xylene was dropped into the reactor again. After the dehydration reaction was completed, a small amount of the powdered aminoethanol sulfate ester produced was collected, and the purity after drying was measured and found to be 98.2%.

Next, the xylene in which the aminoethanol sulfate ester was suspended was cooled to below 50°C, and a 25% aqueous solution of sodium hydroxide equivalent to twice that of the aminoethanol sulfate ester was charged into the reactor and thoroughly stirred. .

At this time, the amount of xylene is 0 relative to the sodium hydroxide aqueous solution.
．． A portion was extracted in advance so that the volume ratio was 4. After stirring for about 2 minutes, the mixture was allowed to stand still and the interface was allowed to separate, and the aqueous sodium hydroxide phase in which the aminoethanol sulfate was dissolved and extracted was completely separated as the lower layer, which could be easily separated and recovered. Ta. Example 2 After carrying out a dehydration reaction using the same method and apparatus as in Example 1, 240 ml of xylene was extracted.

To the xylene in the reactor in which the remaining aminoethanol sulfate ester was suspended, 320 g of a 10% aqueous sodium hydroxide solution was added at 50° C. or lower and thoroughly stirred, but the sulfate ester was not completely dissolved. So, 10 more
When 480 g of % aqueous sodium hydroxide solution was added and thoroughly stirred, the sulfuric ester was completely dissolved, and by standing still, it was completely separated into two phases. Example 3 1 mol of monoaminoethanol sulfate and 2 xylene
00 mt was placed in a beaker, and NaOH aqueous solutions of various concentrations were added at 40 to 50° C. under stirring until the monoaminoethanol sulfate was completely dissolved in 5 minutes.

Thereafter, the mixture was allowed to stand still, and if two layers did not form within the e-car, xylene was added, and when two layers formed, the addition of xylene was stopped. The results are shown in the table below. From the results in this table, it can be seen that when the NaOH concentration is less than 10% or exceeds 35%, the amount of NaOH aqueous solution required increases rapidly.

Example 4 Synthesis was carried out in the same manner as in Example 1 using various aminoalkanols.

During the synthesis, no coloring of the organic solvent layer different from 2-aminoethanol was observed. The aminoalkanol used was 2
-amino-1-propanol, 3-amino-1-propanol and 2-amino-benzyl alcohol.
The purity of monoalkanol sulfate ester corresponding to these raw materials was 98.3 wt%, 98.7 wt%, and 99.4 wt%, respectively. The xylene suspension of monoalkanol sulfate was then cooled to 5CfC.

Dissolution extraction was attempted according to Example 1. As a result, thing 2-
For aminobenzyl alcohol sulfate, some floating matter was observed at the interface, but for other substances, complete separation was possible. Example 5 The same synthesis as in Example 1 was carried out using an N-substituted amino alcohol.

However, when the reaction time was 3 hours, the production rate was as low as 72 to 81 mol%, so the reaction was carried out for 6 hours. The N-substituted amino alcohols used were 3-diethylamino-1-propanol, 4-
dimethylamino-1-pentanol and 2-dimethylaminobenzyl alcohol. The purity of the monoalkanol sulfate ester corresponding to these is 97.4.
Wt%, 98.1 Wt% and 97.9 Wt%. Next, the xylene in which the monoalkal sulfuric ester was suspended was cooled to below 50° C., and dissolution and extraction were carried out in accordance with Example 1, resulting in complete separation of all the components.

[Brief explanation of drawings]

The drawing is a graph showing the relationship between the concentration of an aqueous alkali hydroxide solution and the solubility of an aminoalkanol sulfate ester.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R in the formula is represented by the formula -R″'CH- (R″′ is hydrogen or a lower alkyl group) a divalent aliphatic hydrocarbon group or a phenylene group, R' and R'' are hydrogen or a lower alkyl group, and n means an integer of 1 to 3) and sulfuric acid, or The acidic sulfate of the alkanolamine is heated and dehydrated in a suspending solvent, the produced water is removed by azeotropic distillation, and then a 10 to 35% by weight aqueous solution of alkali hydroxide is added to suspend the aminoalkyl acid sulfate. A method for separating an aminoalkyl acid sulfate ester from a suspending solvent, which comprises dissolving the sulfate ester and separating an aqueous alkali hydroxide phase containing the sulfate ester.