CA2157546A1 - Process for preparing alkyl polyglycosides - Google Patents
Process for preparing alkyl polyglycosidesInfo
- Publication number
- CA2157546A1 CA2157546A1 CA002157546A CA2157546A CA2157546A1 CA 2157546 A1 CA2157546 A1 CA 2157546A1 CA 002157546 A CA002157546 A CA 002157546A CA 2157546 A CA2157546 A CA 2157546A CA 2157546 A1 CA2157546 A1 CA 2157546A1
- Authority
- CA
- Canada
- Prior art keywords
- glycosidation
- carried out
- tubular reactor
- alcohol
- reactor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H15/00—Compounds containing hydrocarbon or substituted hydrocarbon radicals directly attached to hetero atoms of saccharide radicals
- C07H15/02—Acyclic radicals, not substituted by cyclic structures
- C07H15/04—Acyclic radicals, not substituted by cyclic structures attached to an oxygen atom of the saccharide radical
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H1/00—Processes for the preparation of sugar derivatives
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- Biotechnology (AREA)
- General Health & Medical Sciences (AREA)
- Genetics & Genomics (AREA)
- Molecular Biology (AREA)
- Crystallography & Structural Chemistry (AREA)
- Saccharide Compounds (AREA)
Abstract
The invention relates to a process for single-stage preparation of alkyl polyglycosides from saccharides and alcohols having 8 to 20 C atoms by acid-catalyzed glyco-sidation. The reaction is carried out using a tubular reactor under co-current flow conditions.
Description
- ~ULS AgTIENGESELLSCHAFT 2157 ~46 O.Z. 4862 - Patentabteilung -Process for preparinq alkyl PolYqlycosides The invention relates to a single-stage process for preparing alkyl polyglycosides by acid-catalyzed reaction of saccharides and alcohols having 8 to 20 C atoms.
Alkyl polyglycosides having C8- to C20- alkyl radicals can be prepared in whole or in part from renewable raw materials. The alkyl polyglycosides are becoming increas-ingly important because of their interesting surfactant properties with, simultaneously, very good biodegradability. For applications in the home and in the cosmetics sector, these products must conform with high aesthetic demands. There is therefore interest in pro-cesses by which alkyl polyglycosides can be prepared in transparent aqueous solutions of attractive colour.
To prepare alkyl polyglycosides having long-chain alkyl groups, alkyl glycosides having Cl- to C6- alkyl groups can first be prepared by glycosidation of saccharides with short-chain alcohols. These products are then converted into the desired alkyl polyglycosides by transglycosidation at elevated temperature with long-chain alcohols. However, the products thus prepared are of dark colour.
Reeping to defined weight ratios, and using solubilizers, the polar saccharides can also be reacted directly with the nonpolar long-chain alcohols to give the alkyl polyglycosides. In this case also, without the addition of colour improvers, dark-coloured products are obtained if the reaction is carried out in a stirred tank.
In EP 0 077 167, a single-stage preparation process is described in which an aldose or ketose is reacted di-rectly with a long-chain alcohol in a molar ratio of 1 : 1.2S to 1 : 4. The reaction is carried out at low water contents in the presence of a reducing agent.
- 2157~4~
This single-stage process is improved in DE-A-41 01 252 by using a large excess of alcohol and using alkali metal hydroxide dissolved in alcohols for neutraliza-tion. The reaction is carried out here in a stirred tank.
Furthermore, it is known that the colour quality of the alkyl polyglycosides can be improved by measures relating to equipment.
Thus, according to EP-A-0 482 325, in a two-stage preparation process, the first stage, the glycosidation of saccharides in aqueous solution with Cl- to C6- alcohols, can be carried out in a counter-current reaction column, for example in a bubble-cap column.
Furthermore, according to DE-A-41 16 665, the transglycosidation, the second stage of the two-stage process, can also be carried out in a reaction column and preferably under counter-current flow conditions.
However, the two-stage process having two columns connected in series is associated with a relatively high expenditure in terms of apparatus.
It is attempted according to the present invention to avoid the disadvantages of the prior art and to prepare light-coloured products without addition of reducing agents in a simple process.
Therefore, according to the invention, in a single-stage preparation of alkyl polyglycosides, the reaction is carried out using a tubular reactor under co-current flow conditions.
Alkyl polyglycosides having C8- to C20- alkyl radicals can be prepared in whole or in part from renewable raw materials. The alkyl polyglycosides are becoming increas-ingly important because of their interesting surfactant properties with, simultaneously, very good biodegradability. For applications in the home and in the cosmetics sector, these products must conform with high aesthetic demands. There is therefore interest in pro-cesses by which alkyl polyglycosides can be prepared in transparent aqueous solutions of attractive colour.
To prepare alkyl polyglycosides having long-chain alkyl groups, alkyl glycosides having Cl- to C6- alkyl groups can first be prepared by glycosidation of saccharides with short-chain alcohols. These products are then converted into the desired alkyl polyglycosides by transglycosidation at elevated temperature with long-chain alcohols. However, the products thus prepared are of dark colour.
Reeping to defined weight ratios, and using solubilizers, the polar saccharides can also be reacted directly with the nonpolar long-chain alcohols to give the alkyl polyglycosides. In this case also, without the addition of colour improvers, dark-coloured products are obtained if the reaction is carried out in a stirred tank.
In EP 0 077 167, a single-stage preparation process is described in which an aldose or ketose is reacted di-rectly with a long-chain alcohol in a molar ratio of 1 : 1.2S to 1 : 4. The reaction is carried out at low water contents in the presence of a reducing agent.
- 2157~4~
This single-stage process is improved in DE-A-41 01 252 by using a large excess of alcohol and using alkali metal hydroxide dissolved in alcohols for neutraliza-tion. The reaction is carried out here in a stirred tank.
Furthermore, it is known that the colour quality of the alkyl polyglycosides can be improved by measures relating to equipment.
Thus, according to EP-A-0 482 325, in a two-stage preparation process, the first stage, the glycosidation of saccharides in aqueous solution with Cl- to C6- alcohols, can be carried out in a counter-current reaction column, for example in a bubble-cap column.
Furthermore, according to DE-A-41 16 665, the transglycosidation, the second stage of the two-stage process, can also be carried out in a reaction column and preferably under counter-current flow conditions.
However, the two-stage process having two columns connected in series is associated with a relatively high expenditure in terms of apparatus.
It is attempted according to the present invention to avoid the disadvantages of the prior art and to prepare light-coloured products without addition of reducing agents in a simple process.
Therefore, according to the invention, in a single-stage preparation of alkyl polyglycosides, the reaction is carried out using a tubular reactor under co-current flow conditions.
- 2~5754~
Suitable tubular reactors generally have a diameter of 0.5 to 50 cm and a length of 0.5 to 50 m, where the length is to be at least 4 times the diameter. In the simplest case this is a heatable tube. Preferably, however, the tubular reactor is also provided with a plurality of nozzles via which the vacuum can be applied and water which is introduced and formed can be taken off.
The tubular reactor can also contain chicanes and turbulence-generating internals. The tube can be arranged I0 horizontally, at an incline or vertically so that in the context of this invention columns, for example bubble-cap columns, are also considered to be tubular reactors. However, it must be noted in this context that the reaction components are conducted in co-current flow.
The saccharides used can be aldoses or ketoses.
Examples of these are glucose, mannose, galactose and fructose, glucose being preferably used. The saccharides can be used in the anhydrous state or as an aqueous syrup.
Alcohols suitable for the present process are general monoalcohols, preferably linear primary monoalcohols having 8 to 20 carbon atoms, for example octanol, decanol, lauryl alcohol, myristyl alcohol, palmityl alcohol and stearyl alcohol. Mixtures of alcohols can also be used.
Preferably, alchohols having 8 to 12 C atoms are used.
The saccharide/alcohol molar ratio is preferably in the range from 1 : 2 to 1 : 10.
Catalysts which are suitable are mineral acids and strong organic acids. Examples of these are sulphuric acid, 21~7~46 - 3a -phosphoric acid and p-toluenesulphonic acid. The catalyst is preferably used in concentrations of 0.2 to 5 %, based on the saccharide.
The reaction is usually carried out at a temperature of 50 to 140C, temperatures of 70 to 130C being particularly preferred.
At the same time, a mean residence time of 5 to 90 minutes is preferably set.
2157~
~ - 4 - O.Z. 4862 The process is preferably carried out continuously. The products generally have a mean degree of glycosidation of 1 to 10, mean degrees of glycosidation of 1.1 to 4 being particularly preferably set and mean degrees of glycosi-S dation of 1.1 to 1.4 being very particularly preferablyset.
By means of the present invention, in particular in the case of continuous synthesis plants, the expenditure in term~ of apparatus is greatly decreased. Owing to the short residence times and the narrow residence time distributions, light products of high quality are obtained because of the low thermal stress. The products are of light colour when their 50 % strength aqueous solutions have iodine colour values of < 60 before the HzO2 bleaching.
After the reaction the product is neutralized with a base in a known manner, wheleu~o~ excess fatty alcohol is separated off by distillation. The product is then generally mixed with water and bleached with H2O2.
When the invention is carried out in practice, stirred tanks can also be connected upstream or downstream of the tubular reactor. Thus, for example, when syrup is used, water can be removed under a low vacuum at 70 to 130C in the stirred tank before catalyst is added and the mixture is passed to the tubular reactor. The water can also be stripped using inert gas. The catalyst can also already be added to an upstream stirred tank so that in addition to the removal of water, some of the compounds react. The reaction mixture which has begun to react is then prefer-ably homogenized via a mixer and passed into the tubularreactor. Downstream stirred reactors generally serve only to increase the residence time and to complete the reaction. Preferably, 5 to 80 %, in particular cases 10 to 60 %, of the reaction is carried out in a tubular reactor.
~t 57~6 - - 5 - O.Z. 4862 ~xample A 25 1 stirred reactor is fed with a mixture of 14.7 kg of fatty alcohol (66 % dodecanol, 28 % tetradecanol, 6 %
hexadecanol) and 1.8 kg of anhydrous glucose per hour. By addition of p-toluenesulphonic acid, a catalyst concen-tration of 0.25 per cent by weight is maintained in the reactor. The mean residence time is 30 minutes. At an intern~l temperature of 110C, a vacuum of 30 mbar i8 applied so that reaction water can be distilled off rapidly. The reactor discharge still has a glucose content of 2.1 %.
The reaction mixture is passed through a static mixer and then through a heatable tube having an internal diameter of 10 cm and a length of 175 cm. The reaction mixture contains 77.6 % fatty alcohol, 12.9 % alkyl glucoside having a mean degree of glycosidation of 1.26 and < 0.1 %
glucose.
Suitable tubular reactors generally have a diameter of 0.5 to 50 cm and a length of 0.5 to 50 m, where the length is to be at least 4 times the diameter. In the simplest case this is a heatable tube. Preferably, however, the tubular reactor is also provided with a plurality of nozzles via which the vacuum can be applied and water which is introduced and formed can be taken off.
The tubular reactor can also contain chicanes and turbulence-generating internals. The tube can be arranged I0 horizontally, at an incline or vertically so that in the context of this invention columns, for example bubble-cap columns, are also considered to be tubular reactors. However, it must be noted in this context that the reaction components are conducted in co-current flow.
The saccharides used can be aldoses or ketoses.
Examples of these are glucose, mannose, galactose and fructose, glucose being preferably used. The saccharides can be used in the anhydrous state or as an aqueous syrup.
Alcohols suitable for the present process are general monoalcohols, preferably linear primary monoalcohols having 8 to 20 carbon atoms, for example octanol, decanol, lauryl alcohol, myristyl alcohol, palmityl alcohol and stearyl alcohol. Mixtures of alcohols can also be used.
Preferably, alchohols having 8 to 12 C atoms are used.
The saccharide/alcohol molar ratio is preferably in the range from 1 : 2 to 1 : 10.
Catalysts which are suitable are mineral acids and strong organic acids. Examples of these are sulphuric acid, 21~7~46 - 3a -phosphoric acid and p-toluenesulphonic acid. The catalyst is preferably used in concentrations of 0.2 to 5 %, based on the saccharide.
The reaction is usually carried out at a temperature of 50 to 140C, temperatures of 70 to 130C being particularly preferred.
At the same time, a mean residence time of 5 to 90 minutes is preferably set.
2157~
~ - 4 - O.Z. 4862 The process is preferably carried out continuously. The products generally have a mean degree of glycosidation of 1 to 10, mean degrees of glycosidation of 1.1 to 4 being particularly preferably set and mean degrees of glycosi-S dation of 1.1 to 1.4 being very particularly preferablyset.
By means of the present invention, in particular in the case of continuous synthesis plants, the expenditure in term~ of apparatus is greatly decreased. Owing to the short residence times and the narrow residence time distributions, light products of high quality are obtained because of the low thermal stress. The products are of light colour when their 50 % strength aqueous solutions have iodine colour values of < 60 before the HzO2 bleaching.
After the reaction the product is neutralized with a base in a known manner, wheleu~o~ excess fatty alcohol is separated off by distillation. The product is then generally mixed with water and bleached with H2O2.
When the invention is carried out in practice, stirred tanks can also be connected upstream or downstream of the tubular reactor. Thus, for example, when syrup is used, water can be removed under a low vacuum at 70 to 130C in the stirred tank before catalyst is added and the mixture is passed to the tubular reactor. The water can also be stripped using inert gas. The catalyst can also already be added to an upstream stirred tank so that in addition to the removal of water, some of the compounds react. The reaction mixture which has begun to react is then prefer-ably homogenized via a mixer and passed into the tubularreactor. Downstream stirred reactors generally serve only to increase the residence time and to complete the reaction. Preferably, 5 to 80 %, in particular cases 10 to 60 %, of the reaction is carried out in a tubular reactor.
~t 57~6 - - 5 - O.Z. 4862 ~xample A 25 1 stirred reactor is fed with a mixture of 14.7 kg of fatty alcohol (66 % dodecanol, 28 % tetradecanol, 6 %
hexadecanol) and 1.8 kg of anhydrous glucose per hour. By addition of p-toluenesulphonic acid, a catalyst concen-tration of 0.25 per cent by weight is maintained in the reactor. The mean residence time is 30 minutes. At an intern~l temperature of 110C, a vacuum of 30 mbar i8 applied so that reaction water can be distilled off rapidly. The reactor discharge still has a glucose content of 2.1 %.
The reaction mixture is passed through a static mixer and then through a heatable tube having an internal diameter of 10 cm and a length of 175 cm. The reaction mixture contains 77.6 % fatty alcohol, 12.9 % alkyl glucoside having a mean degree of glycosidation of 1.26 and < 0.1 %
glucose.
Claims (8)
1. A process for preparing an alkyl polyglycoside, which comprises an acid-catalyzed glycosidation of a saccharide with an alcohol having 8 to 20 carbon atoms using a tubular reactor under co-current flow conditions.
2. A process according to claim 1, wherein the glycosidation is carried out at 70 to 130°C.
3. A process according to claim 1, wherein a mean residence time in the tubular reactor is 5 to 90 minutes.
4. A process according to claim 1, wherein an alcohol having 8 to 12 carbon atoms is used.
5. A process according to claim 1, wherein 5 to 80 %
of the glycosidation is carried out in the tubular reactor.
of the glycosidation is carried out in the tubular reactor.
6. A process for preparing an alkyl polyglycoside having a C8 to C20 alkyl group and a mean glycosidation degree of 1.1 to 1.4, which comprises:
a glycosidation of glucose with an alcohol having 8 to 20 carbon atoms at a glucose/alcohol molar ratio of 1:2 to 1:10 at a temperature of 50 to 140°C in the presence of an acid catalyst, wherein at least a part of the glycosidation reaction is carried out under co-current flow conditions in a tubular reactor having a diameter of 0.5 to 50 cm and a length of 0.5 to 50 m, provided that the length is at least 4 times the diameter, for a mean residence time of 5 to 90 minutes, and wherein, when only a part of the glycosidation is carried out in the tubular reactor, the remainder of the glycosidation is carried out in a stirred reactor connected upstream or downstream of the tubular reactor.
a glycosidation of glucose with an alcohol having 8 to 20 carbon atoms at a glucose/alcohol molar ratio of 1:2 to 1:10 at a temperature of 50 to 140°C in the presence of an acid catalyst, wherein at least a part of the glycosidation reaction is carried out under co-current flow conditions in a tubular reactor having a diameter of 0.5 to 50 cm and a length of 0.5 to 50 m, provided that the length is at least 4 times the diameter, for a mean residence time of 5 to 90 minutes, and wherein, when only a part of the glycosidation is carried out in the tubular reactor, the remainder of the glycosidation is carried out in a stirred reactor connected upstream or downstream of the tubular reactor.
7. A process of claim 6, wherein 5 to 80 % of the glycosidation is carried out in the tubular reactor and the remainder is carried out in the stirred reactor.
8. A process of claim 7, wherein the remainder of the glycosidation is carried out in the stirred reactor connected upstream of the tubular reactor in the presence of the acid catalyst while removing water under vacuum.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4431858.8 | 1994-09-07 | ||
| DE4431858A DE4431858A1 (en) | 1994-09-07 | 1994-09-07 | Process for the preparation of alkyl polyglycosides |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2157546A1 true CA2157546A1 (en) | 1996-03-08 |
Family
ID=6527634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002157546A Abandoned CA2157546A1 (en) | 1994-09-07 | 1995-09-05 | Process for preparing alkyl polyglycosides |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0700925A1 (en) |
| JP (1) | JPH08176181A (en) |
| KR (1) | KR960010673A (en) |
| CN (1) | CN1129704A (en) |
| CA (1) | CA2157546A1 (en) |
| DE (1) | DE4431858A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6100391A (en) * | 1999-01-04 | 2000-08-08 | Henkel Corporation | Method for making an alkyl glycoside |
| DE10163240A1 (en) * | 2001-12-21 | 2003-07-10 | Cognis Deutschland Gmbh | Process for bleaching surface-active compounds |
| DE102004025195A1 (en) * | 2004-05-22 | 2005-12-08 | Goldschmidt Gmbh | Process for the preparation of alkyl glycosides |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4223129A (en) * | 1978-09-01 | 1980-09-16 | A. E. Staley Manufacturing Company | Continuous process for making alkyl aldosides from starch or other carbohydrates |
| DE3266210D1 (en) | 1981-10-08 | 1985-10-17 | Rohm & Haas France | A process for preparing surface-active glycosides and the use of the glycosides in cosmetic, pharmaceutical and household products |
| US4939245A (en) * | 1988-12-21 | 1990-07-03 | Henkel Kommanditgesellschaft Auf Aktien | Process for the direct production of glysoside product in the presence of solid saccharide |
| DE4034074A1 (en) | 1990-10-26 | 1992-04-30 | Huels Chemische Werke Ag | METHOD FOR PRODUCING ALKYL GLYCOSIDES AND ALKYLOLIGOGLYCOSIDES |
| EP0492397A1 (en) * | 1990-12-26 | 1992-07-01 | Kao Corporation | Process for producing alkyl glycoside |
| DE4101252A1 (en) | 1991-01-17 | 1992-07-23 | Huels Chemische Werke Ag | METHOD FOR PRODUCING ALKYLGLYCOSIDES AND ALKYLPOLYGLYCOSIDES |
| DE4116665A1 (en) | 1991-05-22 | 1992-11-26 | Huels Chemische Werke Ag | PROCESS FOR THE PREPARATION OF ALKYLPOLYGLYCOSIDES |
-
1994
- 1994-09-07 DE DE4431858A patent/DE4431858A1/en not_active Withdrawn
-
1995
- 1995-07-12 EP EP95110921A patent/EP0700925A1/en not_active Withdrawn
- 1995-09-05 CA CA002157546A patent/CA2157546A1/en not_active Abandoned
- 1995-09-06 KR KR1019950029072A patent/KR960010673A/en not_active Application Discontinuation
- 1995-09-06 JP JP7229347A patent/JPH08176181A/en not_active Withdrawn
- 1995-09-06 CN CN95116219A patent/CN1129704A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE4431858A1 (en) | 1996-03-14 |
| EP0700925A1 (en) | 1996-03-13 |
| JPH08176181A (en) | 1996-07-09 |
| KR960010673A (en) | 1996-04-20 |
| CN1129704A (en) | 1996-08-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |