JPS6232101A - Method for purifying hydroxyethyl cellulose - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for purifying hydroxyethyl cellulose (hereinafter referred to as HEC).

Specifically, the present invention relates to a method for removing the alkali metal content from the cellulose by treating the cellulose with an organic solvent containing a dispersible alkyl phosphate or a mixed solvent of an organic solvent and water.

[Conventional technology]

HEC is a nonionic water bathing polymer, and its aqueous solution has viscosity and is excellent in stability and compatibility with salts.

In addition, its aqueous solution is stable without gluing at low or high temperatures, and has the property of acting as a protective colloid. Furthermore, H.E.
The C aqueous solution has film-forming properties, and the resulting film is transparent, flexible, and non-sticky.

Taking advantage of these excellent properties, HEC is widely used as a water-soluble thickener, dispersant, binder, etc.

Methyl cellulose, ethyl cellulose, and hydroxypropyl cellulose, which are water-soluble cellulose ethers similar to HEC, are used as catalysts in the etherification reaction of cellulose contained in cellulose ether because they become dull when heated in an aqueous solution. Alkali metal components such as N& or Ni can be easily removed. However, since HEC is also soluble in hot water, it is very difficult to remove Na or salt contained in the product. For this reason, many methods have been proposed for removing Na or salt contained in HEC.

For example, Japanese Patent Publication No. 37-848 discloses that the reaction product is neutralized with globionic acid, or benzoic acid, or acetic acid and nitric acid,
70-90% hydrophilic solvent
j-butanol, a@c-butanol, dioxane)
A method of cleaning in combination with an aqueous solution has been proposed.

Further, Japanese Patent Application Laid-Open No. 50-83427 describes a method for removing ash contained in HEC using a cation exchange resin.

On the other hand, Japanese Patent Publication No. 44-13159 proposes a method in which EC is treated with glyoxol in an acidic region and the water is drained and washed with water.
In Publication No. 3402, Grioki.

A method is disclosed in which the glyoxalated HEC (treated with sol) is dried at 40-80°C, and then the glyoxalated HEC is washed with water at a temperature below 10°C and dried again.

[Problem that the invention seeks to solve]

However, the method disclosed in Japanese Patent Publication No. 37-848 not only requires a large amount of solvent for washing, but also makes it difficult to obtain highly pure HEC even after repeated washing. Also, JP-A No. 50-83427! In the published method, HEC
In addition to the low efficiency of ion exchange resins due to the thickening properties of aqueous solutions,
Its reproduction is extremely difficult. On the other hand, the special public
It is difficult to sufficiently remove the ash content in HEC depending on the method disclosed in Publication No. 159. In addition, the special public official 58-434
The method disclosed in Japanese Patent No. 02 is also complicated in operation and causes a lot of HEC loss.

-Na or a salt contained in HEC is inherently water-bathable and hardly dissolves in organic solvents. Therefore, in order to remove Na or salt from HEC, washing with water or an aqueous organic solvent may be considered, but since HEC itself is also water-soluble, washing with an aqueous organic solvent is unavoidable) (112C
losses cannot be avoided.

Means for Solving Problem C] As a result of repeated studies by Kaede, the present inventors discovered that NaOH, Na salt, or KOI (or Ni salt) has 1 or 2 carbon atoms The inventors have discovered that the present invention has an extremely high solubility in a mixed solvent of an acidic phosphoric acid ester containing phosphoric acid, a nonpolar organic solvent, a polar organic solvent, and/or water.

(Structure of the Invention) That is, the present invention provides the following features: (1) In the 6m15 method for hydroxyethyl cellulose, the cellulose is treated with a mixed solvent of a polar organic solvent containing an acidic alkyl phosphate ester and a non-polar organic solvent, or a polar organic solvent containing the phosphate ester. The alkali metal content contained in the cellulose is removed by treatment with a solvent or/and a mixed solvent of a non-polar organic solvent and water (2)
The method according to claim 1, wherein the alkyl group of the acidic alkyl phosphate ester has 4 to 18 carbon atoms, (3) the acidic alkyl phosphate ester has a carbon number of 0.4 to 1 mole of alkali metal ion in the cellulose. (4) The method according to claim 1, wherein the amount of the mixed solvent is 1 to 200 times the weight of the cellulose.

It is.

(Detailed Description of the Invention) (1-HEC) The HEC used in the present invention can be prepared by a conventionally known method and can be used as is. In the mixed liquid slurry, cellulose is reacted with an alkali to form alkali cellulose, and then EO is added to combine the alkali cellulose and E.
Examples include a method of reacting with O to form HEC. Also,
Synthesis methods that do not use solvents may also be used.

Note that the alkali metal content contained in HEC is H
In addition to remaining alkalis such as caustic soda and caustic potash used in the production of EC, the term refers to neutralized salts of these alkalis (eg, common salt, sodium acetate, potassium chloride, potassium acetate), and the like.

(2) Acidic alkyl phosphate ester The acidic alkyl phosphate ester used in the present invention has an alkyl group having 4 to 18 carbon atoms, and among these, those having 4 to 8 carbon atoms are preferable. Examples of such esters include phosphoric acid diisopropyl ester, phosphoric acid diptyl ester, phosphoric acid di(2-ethylhexyl) ester, phosphoric acid diphenyl ester, phosphoric acid methyl ester, phosphoric acid ethyl ester, phosphoric acid isodecyl ester, phosphoric acid e2-ethylhexyl ester, Phosphite dipyl ester, phosphite didodecyl ester, phosphite diphenyl ester, etc. are used, and among these, phosphoric acid diptyle ester and phosphoric acid no(2-ethylhexyl) ester; AE is preferred.

These phosphoric esters are used to neutralize the caustic alkali remaining in Ic and to solubilize the neutralized salt and the alkali metal salt contained in HEC in an organic solvent. .

The amount of phosphoric acid ester used must be sufficient to remove the alkali remaining in HEC, but it is usually 0.4 to 1 mole of alkali metal ion in HEC. 3 mol, preferably 0.6 to 1.
It is 2 moles.

(3) Organic solvents Organic solvents used in the present invention include polar organic solvents and non-polar organic solvents. Examples of polar organic solvents include:
methanol, ethanol.

Improper tool, 1-butanol, t-butanol,
Alcohols such as amyl alcohol, 2-ethylhexanol, cyclohexanol, and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; acetate esters such as ethyl acetate; butyrate esters; There are esters such as Among these, methanol, t-butanol, ethyl acetate and the like are particularly preferred.

Examples of non-polar organic solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, benzene, mineral spirits, decalin, tetralin, p-cymene, benzene, toluene, etc. Of these, hexa/, toluene, etc. are particularly preferred.

There is no particular limit to the amount of organic solvent used, but 1
It is preferable to use up to 200 times the amount by weight. If the amount used is less than 1 part by weight, the cleaning effect will not be sufficient, and if it exceeds 200 parts by weight, it will be economically disadvantageous in terms of solvent recovery, etc.

In addition, when using a combination of polar and non-polar solvents,
Although there are no particular restrictions on the combinations and their mixing ratios, combinations of methanol, t-butanol, tohexane, toluene, etc. are preferred.

(4) Water In the method of the present invention, it may be necessary to use water in addition to an organic solvent, but pure water is used as the washing water, such as deionized water, distilled water, etc. I can list them. The amount used is not particularly limited, but is usually 0.5 to 15 vol, preferably 1 to 10 vot, % per 100 parts by volume of the organic solvent. Note that water may not be necessary depending on the case, but if water is used extensively, it is effective in removing alkali metal components, but the loss of HEC is large and it is not economical.

(5) Cleaning treatment conditions The HEC cleaning treatment temperature in the present invention is 10 to 110°C.
The temperature is preferably 20 to 70°C.

If the cleaning temperature is too low, it will take a long time to dissolve the alkali metal component, resulting in insufficient cleaning effect, and if the cleaning temperature is too high, organic solvent vapor will be generated, which is not preferable.

The time for adding a solvent to HgC and mixing it will vary depending on the equipment used, the amount of raw materials charged, the type and amount of solvent, the temperature, etc., but in short, it is necessary to ensure that the alkali metal content from HEC is sufficiently removed. It is desirable that the test be carried out for at least 1 minute, and usually for 3 minutes or more.

The process for implementing the present invention basically consists of a solvent mixing and cleaning step, a HEC separation step, and a solvent recovery step.

In the mixing step, raw materials, acidic phosphoric acid esters, and solvents are fed into an autoclave at a predetermined weight ratio and thoroughly mixed at a predetermined temperature. The lower limit of the pressure at this time is determined as the pressure at which the solvent does not vaporize at that temperature, and is generally preferably normal pressure to 10 kg/crIL2. Mixing can also be performed using a mixer or the like. After the target alkali metal content is dissolved, it is supplied to the slug IJ-k separation process! Ru.

In the separation step, the slurry is separated into NEC and liquid using a slurry'-ft filtration device or a centrifugal separator. ? The remer is washed with a predetermined rinsing liquid at a predetermined temperature.

The rinsed HEC is turned into a dry powder by removing the solvent using dry N2 or the like.

On the other hand, the solvent used in the filtrate and rinse is separated into a solvent and an oil by ordinary distillation or flashing in the solvent recovery process, and a low-viscosity oil is obtained. Furthermore, it is possible to separate the tear fluid and the solvent used for rinsing in advance, use part or all of the fluid used for rinsing as a mixed solvent for HEC cleaning, and subject only the tear fluid to the solvent recovery process. The solvent and acidic phosphate ester will also be collected and reused.

In addition, the HEC after washing becomes a pure C product when dried and crushed.

In addition, without drying the purified product, add a predetermined amount of water and
When heated above, it dissolves and becomes a transparent viscous liquid, which can also be used as it is as a binder, etc.

〔Example〕

The content of the present invention will be explained in more detail below with reference to Examples.

Example 1 HEC60 in t-BuOH containing unneutralized NaOHf
，! I did it. After separating the cake by filtration, toluene 50
0CC1 water 200Ce! In addition, the supernatant was removed. Furthermore,
After adding 500 CCt of toluene and 100 CCt of water and stirring well, the supernatant was removed. Furthermore, 500 eC of toluene and 50 eC' of water were added, and after stirring, the supernatant was removed.

Next, the mixture was washed with HEC' (J) using acetone 1000 ee, filtered to remove water, dehydrated, and dried under reduced pressure.

The ash content in the purified HEC obtained was 0.05%.

Example 2 HEC in t-BuOH contained in unneutralized NILOH'
60g (ash content approximately 20t), hexane 500ccK
Approximately 60.9 g of dissolved di-2-ethylhexyl phosphate was added to neutralize, and then filtered. The resulting cake wot-BuOH
Washing and filtration using 275Ce'i mixture of 1/10 /hexane were performed twice.

Take half of the cake for analysis, and add 2 g of di-2-ethylhexyl phosphate and 25 c of t-BuOT to the remaining HFJC.
c, 25 Q cc of hexane was added to wash, and the solvent was filtered. Furthermore, washing was performed twice using a mixed solution of t-BuOH/hexane = 1/10 275Q (J). After drying under reduced pressure,
The total ash content of HEC was measured at 0.28 and 0.0, respectively.
Example 3 Commercially available ngc <ash content approximately 21 g) 10 g of di-2-ethylhexyl phosphate/10 g
A hexane mixture was added, thoroughly stirred, and then filtered to separate the cake. 5% methanol/hexane mix '110 with additional 3% di-2-ethylhexyl phosphate
After adding 0 cc and stirring well, filtration was performed.

The resulting cake was washed using 150 ccl of hexane. After removing hexane by filtration, it was dried under reduced pressure.

The ash content in purified HEC was 3.97%.

〔Effect of the invention〕

According to the purification method of the present invention, the alkali metal content contained in HEC can be efficiently and effectively removed without loss of HECi.

HEC purified by the method of the present invention can be advantageously used, for example, as a binder in ceramics, fluorescent tubes, and paints.

Claims (4)

[Claims] (1) In the method for purifying hydroxyethyl cellulose, the cellulose is purified by a mixed solvent of a polar organic solvent containing an acidic alkyl phosphate ester and a non-polar organic solvent, or a polar organic solvent containing the phosphate ester and/or a non-polar organic solvent and water. A method for purifying hydroxyethyl cellulose, which comprises removing alkali metal content contained in the cellulose by treating it with a mixed solvent. (2) The method according to claim 1, wherein the alkyl group of the acidic alkyl phosphate ester has 4 to 18 carbon atoms. (3) The method according to claim 1, wherein the acidic alkyl phosphate ester is used in an amount of 0.4 to 2 moles per mole of alkali metal ion in the cellulose. (4) The method according to claim 1, wherein the mixed solvent is 1 to 200 times the weight of the cellulose.