JP3476513B2 - Method for producing alkyl glycoside - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an alkylglycoside having a low unreacted higher alcohol content and a high quality in terms of hue and odor.

[0002]

BACKGROUND OF THE INVENTION Alkyl glycosides, which are sugar derivative surfactants, are stable by themselves in spite of being mild surfactants and nonionic surfactants. It is known that it not only produces a natural foam, but also acts as a foam stabilizer against other anionic surfactants, and has been attracting attention in recent years.
However, despite the remarkable properties of alkyl glycosides as new surfactants as described above, many difficulties are involved in the actual production thereof.

Since alkyl glycosides are usually produced by the reaction of sugars with excess higher alcohols, it is unavoidable to remove the unreacted higher alcohols from the alkyl glycosides prior to their actual use as surfactants. It is desirable to remove unreacted higher alcohol from the alkylglycoside reaction product as much as possible. because,
This is because the odor of the residual higher alcohol itself leads to the deterioration of the odor of the product containing the alkyl glycoside.

The excess higher alcohol can be separated and removed by a known means such as distillation, but the melting point of the alkyl glycoside is generally high, and it is necessary to heat it in order to make it a fluid which can be actually pumped. On the other hand, the thermal stability of most alkyl glycosides is limited, and even a slight thermal history tends to deteriorate the hue of the product and produce sugar alcohols.

Therefore, a method for removing unreacted higher alcohol without causing deterioration of the hue of the alkyl glycoside has been researched, and several methods have been proposed. For example, as described in JP-A-58-194902, a thin film of a reaction product containing an excessive amount of unreacted higher alcohol is formed, and an excessive amount of an excessive amount of high-grade alcohol at an extremely short residence time is formed at a relatively high temperature. A method of evaporating alcohol, or, as described in JP-A-64-47796, optionally presenting a small amount of a short-chain alkyl (C1-5) saccharide to improve fluidity at lower temperatures. However, as described in JP-A-62-192396, the boiling point at 760 mbar is 50 ° C. or more higher than that of the unreacted higher alcohol, as described in JP-A-62-192396. Although a method of adding one or several viscosity reducing agents having activity as a cleaning aid and removing excess higher alcohol at a temperature at least 20 ° C. lower than the decomposition temperature of the alkyl glycoside has been proposed. In any of the methods, the unreacted higher alcohol is removed up to about 0.5% by weight based on the alkyl glycoside in order that the hue of the obtained alkyl glycoside is not sufficiently good or the hue of the alkyl glycoside is not deteriorated. It is not a satisfactory method, because it is at the limit or requires a second component other than the alkyl glycoside.

On the other hand, as a method for solving these problems, Japanese Unexamined Patent Publication (Kokai) No. 3-106895 discloses a reaction product containing an excessive amount of unreacted higher alcohol, and an unreacted higher alcohol content of 3 to 10 is obtained by a known technique. After reducing to wt%, the unreacted higher alcohol-containing alkyl glycoside is made to flow in a thin film form, brought into contact with water vapor or an inert gas, and the unreacted higher alcohol is removed at a relatively low temperature to suppress the deterioration of hue, In addition, the unreacted higher alcohol content is 0.5% by weight.
The method of reducing is disclosed below. However, when the unreacted higher alcohol content is reduced from 3% by weight or more to 0.5% by weight or less, since a large amount of steam or an inert gas is used, the alkyl glycosides are likely to be entrained and the alkyl glycosides may be clogged in the condenser. In addition to troubles, there are many uneconomical alkyl glycosides that are lost to the outside of the system, and further, since a large condenser is required, there is a problem that expensive capital investment is required.

[0007]

Means for Solving the Problems The present inventors have improved the above-mentioned problems of the prior art, are not complicated in operation, and have a low unreacted higher alcohol content without using a second component or the like,
The present invention has been completed as a result of intensive research on a method for economically producing a high-quality alkyl glycoside with respect to hue and odor. That is, in the present invention, a sugar is directly reacted with an aliphatic higher alcohol having 10 to 16 carbon atoms (hereinafter referred to as a higher alcohol), or a sugar is reacted with a lower alcohol and then reacted with a higher alcohol. By a method for producing an alkyl glycoside for removing unreacted higher alcohol from an alkyl glycoside reaction product containing an unreacted higher alcohol obtained by the method, the content of unreacted higher alcohol is low, which is characterized by performing the following steps: It is intended to provide a method for producing a high-quality alkyl glycoside with respect to odor.

[First Step] Content of higher alcohol in alkylglycoside reaction product [(weight of higher alcohol) /
Until [(weight of alkyl glycoside) + (weight of higher alcohol)] x 100] is at least 2.5% by weight or less,
Unreacted higher alcohol-containing alkyl glycosides (hereinafter referred to as crude alkyl glycosides) by removing higher alcohols
To obtain. [Second step] The crude alkyl glycoside obtained in the first step is flown in a thin film form, and this is mixed with steam or an inert gas at a temperature of 100
~ 200 ℃, pressure 25 ~ 200mmHg in contact with and forming a thin film (hereinafter referred to as a device) superficial superficial velocity of steam or inert gas [volumetric flow rate of steam or inert gas in the device / formed Cross-sectional area of the device perpendicular to the thin film] 10 m
/ Sec or less to obtain an alkyl glycoside having a higher alcohol content of 0.5% by weight or less.

The alkylglycoside reaction product in the present invention is obtained by a well-known reaction method, and is a method in which a saccharide and a higher alcohol are directly reacted in the presence of an acid catalyst, or the saccharide is previously reacted with methanol, ethanol, propanol or It may be obtained by any method of reacting with a lower alcohol such as butanol to form a lower alkyl glycoside and then reacting with a higher alcohol.

The higher alcohol as a raw material of the alkyl glycoside according to the present invention is an aliphatic higher alcohol having 10 to 16 carbon atoms, and examples thereof include n-decyl alcohol, lauryl alcohol, myristyl alcohol and the like.

Monosaccharides, oligosaccharides or polysaccharides are used as the saccharides as the raw material of the alkyl glycoside according to the present invention. Specific examples of monosaccharides include aldoses such as allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose and lyxose. Specific examples of oligosaccharides include maltose, lactose, sucrose, maltotriose and the like. Specific examples of the polysaccharide include hemicellulose, inulin, dextrin, dextran, xylan, starch, hydrolyzed starch and the like.

The reaction for producing an alkyl glycoside in the present invention is carried out according to a known method using the above-mentioned starting materials and conditions such as a catalyst and a reaction temperature. As mentioned above
Although unreacted higher alcohols can be removed from alkylglycoside reaction products containing unreacted higher alcohols by known techniques such as distillation or solvent extraction, a more preferable method for removing unreacted higher alcohols is to remove unreacted higher alcohols. The alkyl glycoside reaction product containing
It is a method in which a thin film is flown and heat and vacuum are applied, and it has been found that the content of unreacted higher alcohol can be removed up to 2% by weight or less (JP-A-58-194902).

However, in order to remove the content of the unreacted higher alcohol to 0.5% by weight or less, preferably 0.2% by weight or less based on the alkyl glycoside, it is indispensable to apply higher temperature in the above method, It is unavoidable that deterioration of quality such as deterioration of hue and deterioration of odor due to thermal decomposition of alkylglycoside is unavoidable, and it is not an appropriate method when the hue and odor of the obtained alkylglycoside are required to have harsh quality. It was

As a method for avoiding the high temperature, a method of increasing the degree of vacuum can be considered, but a high vacuum of 0.5 mmHg or less is required to remove the higher alcohols to the above degree. Therefore, since a specially equipped vacuum device is used in terms of equipment, expensive equipment investment is required.
Further, even if a low-temperature condenser is used, the amount of evaporated higher alcohol is removed to the outside of the system, and an unfavorable problem such as an increase in pollution control costs occurs.

Further, as a method for solving the above-mentioned problem, a reaction product containing an excess of unreacted higher alcohol is made to flow in a thin film form and brought into contact with steam or an inert gas, whereby a vacuum device equipped with extra heavy equipment is provided. A method for removing unreacted higher alcohols under a relatively low vacuum without using a solvent has been found (JP-A-3-106895). However, when unreacted higher alcohols are removed using this method, since a large amount of steam or an inert gas is used, alkyl glycosides are likely to be entrained and cause troubles such as clogging of alkyl glycosides in the condenser. It is uneconomical because there are many alkyl glycosides lost outside the system,
In addition, when steam is used, a large condenser is required, which requires a large amount of equipment investment, and there is little merit by simply using this method.

However, the present inventors have found that when the unreacted higher alcohol content in the alkyl glycoside is at least 2.5% by weight or less, the unreacted higher alcohol-containing alkyl glycoside is caused to flow in a thin film form, and this and steam or an inert gas. Are contacted with each other so that the superficial flow velocity of water vapor or inert gas in the apparatus is 10 m / sec or less, and the splash of alkyl glycosides to the outside of the system is suppressed, and the unreacted high-grade substances in the alkyl glycosides are suppressed. Alcohol content 0.5% by weight
The inventors have found that unreacted higher alcohols can be removed until the following is reached, and completed the present invention. That is, in the first step of the present invention, a reaction product containing an excess of unreacted higher alcohol is used by a known method until the unreacted higher alcohol content in the alkyl glycoside becomes at least 2.5% by weight or less, preferably 0.8% or less. Unreacted higher alcohols are removed to obtain crude alkyl glycosides up to 2.3% by weight, but any known method such as distillation or solvent extraction may be used. When the content of unreacted higher alcohol in the crude alkyl glycoside exceeds 2.5% by weight, the amount of steam or inert gas to be contacted in the second step increases, so that the amount of alkyl glycoside entrained also increases and the condenser Trouble such as clogging of the alkyl glycoside in the interior and loss of the alkyl glycoside to the outside of the system increase. An increase in the amount of alkylglycoside lost to the outside of the system also increases pollution control costs such as wastewater treatment costs. Further, when the removed higher alcohol is used again in the reaction, purification is necessary, but the cost for that is increased and it is economically disadvantageous.

The operating temperature in the second step of the present invention is 1
00-200 ℃, preferably 130-170 ℃, above 200 ℃, due to the thermal decomposition of alkyl glycosides, the deterioration of hue and odor becomes severe, and below 100 ℃, the viscosity becomes extremely high. Not preferable. The operating pressure is 25 to 200 mmHg, more preferably 30 to 150 mmHg. At a pressure higher than 200 mmHg, a large amount of steam or an inert gas will be used, so that the loss of alkylglycoside to the outside of the system due to entrainment will increase. Also, 25mmHg
At lower pressures, the volume flow of steam increases, so
Loss of alkyl glycosides to the outside of the system increases due to entrainment. The superficial velocity of water vapor or inert gas in the device is
It is 10 m / sec or less (superficial flow velocity under operating temperature and pressure conditions), preferably 7 m / sec or less, more preferably 1 m / sec or more and 7 m / sec or less. When it exceeds 10 m / sec, the amount of alkyl glycosides entrained in the droplets increases, which causes troubles such as clogging of the alkyl glycosides in the condenser and loss of the alkyl glycosides to the outside of the system.

The higher alcohol content in the alkyl glycoside obtained by the second step of the present invention is 0.5% by weight or less, preferably 0.3% by weight or less, and particularly preferably.
It is 0.2% by weight or less. When the content of higher alcohol is more than 0.5% by weight, the irritating odor derived from higher alcohol reduces the commercial value when the alkylglycoside is used as a detergent for direct use or contact with human body such as skin cleanser, shampoo and dishwashing detergent. Therefore, it is not preferable.

The amount of steam or inert gas blown in is not particularly limited, and can be arbitrarily selected depending on the degree of removal of unreacted higher alcohol. When vaporization is carried out under a stream of water vapor or an inert gas, the partial pressure lowering action accelerates the vaporization of unreacted higher alcohols. At this time, it is effective to apply steam or an inert gas flow to the alkylglycoside product forming the thin film in any of countercurrent flow, cocurrent flow and cross flow. Any inert gas may be used as long as it has no reactivity with the alkyl glycoside product, but nitrogen, carbon dioxide gas, air or the like is preferable.

The thinner the thin film, the more preferable it is, but it is not particularly limited, and it is sufficient that it can be obtained by a commercially available thin film evaporator, but it is usually preferably about 10 mm or less. As a device for forming a thin film, an ordinary thin film evaporator can be used. For example, a Smith type thin film evaporator (manufactured by Shinko Pantech Co., Ltd.), a Hitachi Contoro device (manufactured by Hitachi, Ltd.), a Reuwa thin film evaporator (manufactured by Reuwa Co., Ltd.) and the like can be mentioned. These are all devices forcibly forming a thin film, but a natural thin film forming type device such as a falling film type can also be used.

[0021]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples.

Example 1 (a) Lauryl alcohol was used in an amount of 5 moles with respect to anhydrous glucose, and paratoluenesulfonic acid monohydrate was used in an amount of 0.0035 moles with respect to anhydrous glucose.
The reaction was carried out at 0 mmHg in a stirring tank to obtain an alkylglycoside reaction product containing 72.9% by weight of unreacted lauryl alcohol. (b) (First step) Next, the alkylglycoside reaction product obtained in (a) was introduced into a contro evaporator (manufactured by Hitachi Ltd., heat transfer area 0.1 m ² ) at a rate of 15 kg / hr. The crude alkyl glycoside containing 1.0% by weight of unreacted lauryl alcohol was obtained by distillation at 0.9 ° C. and 0.9 mmHg. (c) (Second step) The crude alkyl glycoside obtained in the first step was 20 kg / hr at Smith evaporator (Shinko Pantech Co., Ltd., heat transfer area: 0.2).
m ² ), while blowing steam at 22 kg / hr 1
It was treated under the conditions of 55 ° C. and 70 mmHg. The empty superficial velocity of steam in the apparatus was 6.8 m / sec. Table 1 shows the production conditions, the amount of alkyl glycosides in the second step fraction, the amount of unreacted higher alcohols in the obtained alkyl glycosides, and the odor evaluation results.

Example 2 (a) An alkylglycoside reaction product was obtained in the same manner as in (a) of Example 1. (b) (First step) Next, the alkylglycoside reaction product obtained in (a) was introduced into a contro evaporator (manufactured by Hitachi Ltd., heat transfer area 0.1 m ² ) at a rate of 15 kg / hr. The crude alkyl glycoside containing 2.1% by weight of unreacted lauryl alcohol was obtained by distillation at 1.3 ° C. and 1.3 mmHg. (c) (2nd step) The crude alkyl glycoside obtained in the 1st step is 10 kg / hr in Smith evaporator (Shinko Pantech Co., Ltd., heat transfer area 0.2)
m ² ), while blowing steam at 14 kg / hr 1
It was treated under the conditions of 55 ° C. and 70 mmHg. The superficial velocity of steam in the device was 4.3 m / sec. Table 1 shows the production conditions, the amount of alkyl glycosides in the second step fraction, the amount of unreacted higher alcohols in the obtained alkyl glycosides, and the odor evaluation results.

Comparative Example 1 (a) An alkylglycoside reaction product was obtained in the same manner as in (a) of Example 1. (b) (First step) Next, the alkylglycoside reaction product obtained in (a) was introduced into a contro evaporator (manufactured by Hitachi Ltd., heat transfer area 0.1 m ² ) at a rate of 15 kg / hr. Distillation was performed at 3 ° C. and 3 mmHg to obtain a crude alkyl glycoside containing 3.9% by weight of unreacted lauryl alcohol.

(C) (Second step) The crude alkylglycoside obtained in the first step was mixed with a Smith evaporator (manufactured by Shinko Pantech Co., Ltd., heat transfer area: 0.2) at 20 kg / hr.
m ² ), while injecting steam at 36 kg / hr 1
It was treated under the conditions of 55 ° C. and 70 mmHg. The empty superficial velocity of steam in the apparatus was 11.0 m / sec. Table 1 shows the production conditions, the amount of alkyl glycosides in the second step fraction, the amount of unreacted higher alcohols in the obtained alkyl glycosides, and the odor evaluation results.

Comparative Example 2 (a) An alkylglycoside reaction product was obtained in the same manner as in (a) of Example 1. (b) (First step) Next, the alkylglycoside reaction product obtained in (a) was introduced into a contro evaporator (manufactured by Hitachi Ltd., heat transfer area 0.1 m ² ) at a rate of 15 kg / hr. The crude alkyl glycoside containing 1.2% by weight of unreacted lauryl alcohol was obtained by distillation at 0.9 ° C and 0.9 mmHg. (c) (Second step) The crude alkyl glycoside obtained in the first step was 40 kg / hr in Smith evaporator (manufactured by Shinko Pantech Co., Ltd., heat transfer area: 0.2).
m ² ), while injecting steam at 44 kg / hr 1
It was treated under the conditions of 55 ° C. and 70 mmHg. The superficial flow velocity of steam in the apparatus was 13.6 m / sec. Table 1 shows the production conditions, the concentration of alkyl glycosides in the second step fraction, the amount of unreacted higher alcohols in the obtained alkyl glycosides, and the odor evaluation results.

Comparative Example 3 (a) An alkyl glycoside reaction product was obtained in the same manner as in (a) of Example 1. (b) (First step) Next, the alkylglycoside reaction product obtained in (a) was introduced into a contro evaporator (manufactured by Hitachi, Ltd., heat transfer area 0.1 m ² ) at a rate of 15 kg / hr, Distillation was carried out at 3 ° C. and 3 mmHg to obtain a crude alkyl glycoside containing 4.1% by weight of unreacted lauryl alcohol. (c) (Second step) The crude alkyl glycoside obtained in the first step was 20 kg / hr at Smith evaporator (Shinko Pantech Co., Ltd., heat transfer area: 0.2).
m ² ), while blowing steam at 28 kg / hr 1
It was treated under the conditions of 55 ° C. and 70 mmHg. The superficial velocity of steam in the device was 8.7 m / sec. Table 1 shows the production conditions, the amount of alkyl glycosides in the second step fraction, the amount of unreacted higher alcohols in the obtained alkyl glycosides, and the odor evaluation results.

[0028]

[Table 1]

Note) * 1: 1 g of the alkyl glycoside was dissolved in 100 g of warm water at 40 ° C. and the sensitivity was evaluated by a panelist.

The color of the 35% aqueous solution of the alkyl glycosides obtained in Examples 1-2 and Comparative Examples 1-3 was Gardner 3. Further, in Comparative Examples 1 and 2, when the second step was performed, there was a problem that a large amount of alkyl glycosides adhered to the inside of the distillate condenser, and the distillate condenser was often clogged to raise the pressure.

From Table 1, the amount of unreacted higher alcohol in the crude alkyl glycoside obtained in the first step is 2.5% by weight or less, and in the second step, the superficial flow velocity in the steam apparatus is 10 m / sec or less. By doing so, the amount of splashes of the alkyl glycoside was suppressed to a low level, and the unreacted higher alcohol in the alkyl glycoside in the apparatus was suppressed to 0.5% by weight or less, and an alkyl glycoside having no irritating odor could be obtained (Example 1 2). However, the amount of unreacted higher alcohol in the crude alkyl glycoside obtained in the first step is
If it exceeds 2.5% by weight, the amount of steam to be blown in must be increased in the second step, and the amount of alkyl glycoside droplets increases, causing trouble (Comparative Example 1). Even if the amount of unreacted higher alcohol in the crude alkylglycoside obtained in the first step is 2.5% by weight or less, the superficial flow velocity in the steam apparatus in the second step is
Even when it exceeded 10 m / sec, the amount of alkyl glycoside droplets increased and a trouble occurred (Comparative Example 2). On the other hand, when the amount of steam blown in to reduce the amount of alkyl glycoside splashes was reduced, the unreacted higher alcohol content was 0.5%.
It remained in an amount of more than weight% and had a bad smell (Comparative Example 3).

[0032]

EFFECTS OF THE INVENTION According to the present invention, an alkyl glycoside having a good hue, a very good odor and a very small unreacted higher alcohol content can be obtained extremely economically.

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07H 15/04 CA (STN) WPIDS (STN)

Claims (2)

(57) [Claims] 1. A sugar is directly reacted with an aliphatic higher alcohol having 10 to 16 carbon atoms (hereinafter referred to as a higher alcohol), or after a sugar is reacted with a lower alcohol,
In the method for producing an alkylglycoside for removing an unreacted higher alcohol from an alkylglycoside reaction product containing an unreacted higher alcohol obtained by reacting with a higher alcohol, production of an alkylglycoside characterized by performing the following steps: Method. [First step] Content of higher alcohol in reaction product of alkyl glycoside [(weight of higher alcohol) / [(weight of alkyl glycoside) + (weight of higher alcohol)] × 100]
To remove unreacted higher alcohol-containing alkyl glycoside (hereinafter referred to as "crude alkyl glycoside") until at least 2.5% by weight is obtained. [Second step] The crude alkyl glycoside obtained in the first step is flown in a thin film form, and this is mixed with steam or an inert gas at a temperature of 100
~ 200 ℃, pressure 25 ~ 200mmHg in contact with and forming a thin film (hereinafter referred to as a device) superficial superficial velocity of steam or inert gas [volumetric flow rate of steam or inert gas in the device / formed Cross-sectional area of the device perpendicular to the thin film] 10 m
/ Sec or less to obtain an alkyl glycoside having a higher alcohol content of 0.5% by weight or less. 2. The higher alcohol content of the crude alkylglycoside in the first step is 0.8 to 2.3% by weight, and the higher alcohol content in the alkylglycoside in the second step is 0.2% by weight or less. Method for producing alkyl glycoside.