CA1311503C - Process for the preparation of very high purity sorbitol syrups - Google Patents
Process for the preparation of very high purity sorbitol syrupsInfo
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- CA1311503C CA1311503C CA 485530 CA485530A CA1311503C CA 1311503 C CA1311503 C CA 1311503C CA 485530 CA485530 CA 485530 CA 485530 A CA485530 A CA 485530A CA 1311503 C CA1311503 C CA 1311503C
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H3/00—Compounds containing only hydrogen atoms and saccharide radicals having only carbon, hydrogen, and oxygen atoms
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
- C07C31/18—Polyhydroxylic acyclic alcohols
- C07C31/26—Hexahydroxylic alcohols
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Abstract
PROCESS FOR THE PREPARATION OF VERY HIGH PURITY
SORBITOL SYRUPS
A B S T R A C T
Process for the preparation of very high purity sorbitol syrup, wherein a starting material of which a first part is constituted by a starch hydrolysate, is subjected to a process comprising in combination - a catalytic hydrogenation step of the starting material, - a chromatographic separation step of the start-ing material which has undergone hydrogenation into a first fraction containing very pure sorbitol and which is recovered and into a second fraction containing, besides sorbitol, non-hydrogenated sugars as well as hydrogenated di- and polysaccharides, - an acid hydrolysis step of the abovesaid second fraction, which provides a partially hydrogenated starch hydrolysate which is recycled and which constitutes a se-cond part of the raw material subjected to the hydrogena-tion step.
SORBITOL SYRUPS
A B S T R A C T
Process for the preparation of very high purity sorbitol syrup, wherein a starting material of which a first part is constituted by a starch hydrolysate, is subjected to a process comprising in combination - a catalytic hydrogenation step of the starting material, - a chromatographic separation step of the start-ing material which has undergone hydrogenation into a first fraction containing very pure sorbitol and which is recovered and into a second fraction containing, besides sorbitol, non-hydrogenated sugars as well as hydrogenated di- and polysaccharides, - an acid hydrolysis step of the abovesaid second fraction, which provides a partially hydrogenated starch hydrolysate which is recycled and which constitutes a se-cond part of the raw material subjected to the hydrogena-tion step.
Description
- 131i50~
PROCESS FOR THE PREPARATION OF VERY HI~H PURITY
SOR~ITOL SYRUPS
5The invention relates to a process for the prepa-ration of very high purity sorbitol syrups.
At the present time, very high purity sorbitol syrups are obtained by hydrogenation of dextrose syrups prepared by dissolving crystalline dextrose in water.
10The richness of sorbitol syrups so obtained which is sufficient, however rarely exceeds 98X after purifica-tion.
The reason therefor is that in addition to traces of hydrogenated polyholosides originating in the raw mate-rial and traces of reducing substances which have escaped the hydrogenation, there are formed during the hydrogena-tion, isomers of sorbitol, namely particularly mannitol.
The presence of this group of products results in certain drawbacks in the matter of crystallisation operations of the sorbitol from these syrups and has consequences on the characteristics of the crystalline sorbitol obtained, par-ticularly from the point of view of its crystallinity.
In addition, the yield of the operation is not entirely satisfactory since, to obtain sorbitol syrups ha-ving this richness, which in any case rarely exceeds 98X,it is necessary to satisfy oneself with limited yields at the level of the preceding step of preparation of the crystalline dextrose, which is used for the preparation of the subsequently hydrogenated dextrose syrup, and which is obtained by crystallisation in two or three crops from starch hydrolysates with a glucose content of the order of 94 to 96/. by weight ; in fact, said yields of dextrose are generally limited to about 75 to 77/. in two crops and to about 80 to 88/. after a third crop and the crystallisation mother liquors or hydrols have a sometimes difficult sale in commerce by reason of their color and their content of . .
- i' " 1311~03 impurities.
It has indeed already been proposed to suppress the intermediate crystallisation step of the dextrose by subjecting directly, within the same reaction vessel, a cheaper raw material, namely a starch hydrolysate, not only to reducing c:onditions, but also to hydrolysis by means of a strong acid, which permits also to make use of the conversion known in itself, of polyholosides such as maltitol or isomaltitol into equimolecular amounts of sorbltol and of glucose under the action of the strong acid.
It is possible to mention in this respect French Patent N 1 263 290 which proposes the use, as a catalyst, of reduced nickel on a support constituted of infusorial earth and according to which there is carried out in one and the same reaction vessel, in substantially neutral solution and at a moderately high temperature, a reduction of the major part of the reducing sugars, after which a strong inorganic acid such as phosphoric acid is added, in 20. a proportion of 0.05 to 1.0~ by weight on the basis of the saccharides initially employed, the mixture constituted by the thus acidified solution and the catalyst being sub-jected to higher pressure and temperature, by means of which the hydrolysis of the hydrogenated polyholosides present in the hyd.rolysate and the hydrogenation of the sugars then appearing are effected simultaneously.
Within the same order of ideas, but 15 years later, Belgian Patent N ~37 201 described the simulta-neous hydrogenation-hydrolysis-hydrogenation of starch hydrolysates with use of a ruthenium catalyst supported on zeolite of type Y; the hydrogenation reaction is effected in two steps, the first being conducted at a temperature comprised between 100 and 175 C and the second at a tempe-rature of about 170 to 200-C. The pH conditions in which the consecutive phases of the hydrogenation take place are specified, the pH of the product of the reaction having to 13~1503 be comprised between 3.5 and 4.
The drawbacks of these processes reside not only in the rapid deactivation of the catalysts and in the de-naturation of the structure of the zeolites, but also in S the fact that the syrups so obtained include numerous impurities.
Thus, - there occur partial anhydrysation reaction and isomerisation of the polyols, - the hydrolysis of the hydrogenated polyholoside fraction is incomplete and manifested by a high value of "total sugars", - the proportions of "hexitans", of mannitol, of "total non-sugar impurities" are large, the content of true sorbitol being finally at the most equal to 94X, which is, for example, very insufficient for the prepara-tion of a crystalline sorbitol of suitable quality.
Another process suitable for the preparation of sorbitol syrup without passage through the crystallisation of the dextrose is that described in French Patent N-2 052 202 filed by the Assignee. According to this pro-cess, in which recourse is also had, as starting material, to a starch hydrolysate which is hydrogenated, a fractio-nation of the hydrogenated starch hydrolysate is carried out by passage over a resin or a cationic molecular sieve, preferably in calciurn form, which permits the isolation of a fraction containing sorbitol of richness greater than 99Z .
This technique therefore leads to a sorbitol of very high purity, but it proves however to be unsatisfac-tory in practice. It results, in fact, in a very partial yield of sorbitol, strictly dependant on the true dextrose content of the starting starch hydrolysate, the latter having for this reason to be as high as possible.
It follows that a priori none of the known proces-ses permits at the same time the manufacture of sorbitol 131~503 syrup of high purity, suitable particularly for the preparation of crystalline sorbitol, and an easy access to high yield whose influence on the cost price of the final product is readily seen.
It is to this problem that the Applicants have had the merit of proposing a particularly effective solution, according to which a raw material of which a first part is constituted by a starch hydrolysate, is subjected to a process comprising in combination - a catalytic hydrogenation step of the raw material, - a step of chromatographic separation of the raw material which has undergone hydrogenation into a first fraction containing very pure sorbitol and which is recovered and into a second fraction containing, besides sorbitol, non-hydrogenated sugars as well as hydrogenated di- and polysaccharides, - an acid hydrolysis step of the abovesaid second fraction, which provides a partially hydrogenated starch hydrolysate which is recycled and which constitutes a second part of the raw material subjected to the hyrogenation step.
IN THE DRAWINGS
Figure 1 is a diagrammatic flow sheet illustrating an installation for carrying out the process in accordance with the invention;
~, -4a- ~ 3 ~ 1~ a 3 Figure 2 is a diagrammatic view of an installation suitable for carryi.ng out the chromatographic fractionation step in accordance with the invention;
Figures 3 and 4 are diagrammatic flow sheets representing particular embodiments of the installation proper to carry out the process in accordance with the invention.
The process thus defined may be carried out by means of the installation shown diagrammatically in Figure 1 and which comprises:
- a vessel 201 within which the catalytic hydrogenation step is carried out, - a chromatographic separation installation 202 and - a reaction vessel 203 within which the hydrolysis step is carried out.
The vessel 201 is supplied with raw material. through a pipe 204 formed by the junction at 205 of a pipe 204a bringing in the starch hydrolysate from a tank (not shown) and a pipe 204b connected to the outlet of the vessel 203 and introducing the partially hydrogenated 1~115~
hydrolysate.
The outlet of the vessel 201 is connected to the inlet of the vessel 202 through a pipe 207.
From the outlet of the ~essel 20Z, are conducted :
- the first fraction containing very pure sorbitol through a pipe 208 to a storage tank Inot shown) and - the second fraction containing sorbitol, non-hydrogenated sugars as well as hydrogenated di- and poly-saccharides through a pipe 209 to the inlet of the vessel 10 203.
The means proper to ensure the circulation of the various syrups within the installation are not shown.
The starch hydrolysate which is part of the c~ons-titution of the raw material has, preferably, a true dextrose content comprised between 65 and 97X and, more preferably still, between 70 and 95~/.. Particularly advan-tageous starch hydrolysates are constituted by hydrols of the first and of the second crop obtained in the crystal-lisation of the dextrose.
In the foregoing and in the following, the percen-tages indicated are understood, except when stated to the contrary, with respect to the dry matter of the syrups.
The catalytic hydrogenation step is carried out in manner known in itself, particularly on ruthenium or Raney nickel catalysts. Preferably, it is carried out on a Raney nickel catalyst, at a hydrogen pressure comprised between 40 and 70 kg/cm and at a temperature of about 100 to 150 C.
The chromatographic separation step can be effect-ed, in manner known in itself, discontinously or conti-nuously Isimulated mobile bed), on strongly acid absor-bants of the cationic resin type, charged with alkaline or alkaline earth ions or of the zeolite type, charged with ammonium, sodium, potassium calcium, strontium, or barium ions.
Examples of such chromotographic separation pro-cesses are described in patents US 3 044 904, US 3 416 961, 6 1 3 ~ 3 US 3 692 582, FR 2 391 754, FR 2 099 336, US 2 985 589, US
02~ 331, US 4 226 977, US ~ 293 346, US 4 157 267, US
1~2 633, US ~ 332 633, US 4 405 4~5, US4 ~12 866, and US
4 4~2 ~381.
In a preferred embodiment, the chromatographic se-paration step lS carried out by employing the process and the lnstallation dlsclosed in US Patent N- 4 ~42 881 and its corresponding French Application N 79 10563, published October 14, 1983 under publication no. 2454830.
Whatever the chromatographic separation process adopted, recourse is had, preferably, as adsorbant, to a strong cationic resin placed in the calcium form and hav-ing a proportion of divinyl-benzene from about 4 to about 1 0 1. .
Preferably, the acid hydrolysls step of the above-said second fraction is carried out on a fixed acid cata-lyst and it is conducted so that more than ~OX by weight of the hydrogenated disaccharides and polysaccharides present are hydrolysed.
It is possible to use, to do this, any type of reaction vessel and any reagent or acid catalysts capable of ensuring the hydrolysis of hydrogenated disaccharides and polysaccharides.
Preferably, said hydrolysis is carried out conti-nuously by passing the syrup containing the polyols to be hydrolysed over a fixed bed comprising acid catalysts of the alumino-silicate, silica, alumina or cationic resin type, at a temperature and for a time sufficient to achieve the above indicated desired result.
3n Advantageously, the hydrolysis is conducted on strong cationic resins in the acid form, at a temperature comprised between 50 and 120 C, the passage flow rate over the acid catalyst bed being regulated so as to obtain a hydrolysis ratio of the hydrogenated di- and polysacchari-des at~least equal to 60l. and, preferably, at least equal to 80/..
~'~
``"` 13i 1503 The content of dry matter of the above-said second fraction which is subjected to the hydrolysis step and which is recycled is generally comprised between 1.5~. and 30~ and, preferably, between 2.5 and 20'~.
The process thus described permits sorbitol syrups to be obtained having a richness in sorbitol greater than 9~/., and even greater than 997., which are essentially cha-racterlsed by a minimal content of reducing sugars. These syrups, which have at the outlet from the vessel 202, a content of dry matter comprised between 20~/. and 50'~ and, preferably between 25~/. and 40~, can then be evaporated to the dry matter content for marketing or be evaporated more completely for the production of crystalline sorbitol.
The invention will be still better understood by means of the examples which follow and of the illustrative figures appended hereto, said e~amples relating to prefer-red embodiments of the invention.
Preparation of pure sorbitol from a starch hydrolysate prepared by a double enzymatic hydrolysis with -amylase and amyloglucosidase and having a richness in true dex-trose equal to 94.5~/., its composition being :
Dry Matter (DM) : 74.0 ~/.
De~trose : 94.5 ~/.
Z5 DP 2 : 4.0 DP 3 : 1.0 DP > 3 : o.s it being understood that "DP" means the degree of polyme-risation of a given constituent of the hydrolysate.
a~ Hvdroqenation ste~
The above-said hydrolysate, after purification on ion exchange resins and on active carbon, is hydrogenated on Raney nickel,~at a hydrogen pressure of 45 kg/cm and at a temperature of 125'C.
It shows, after conventional purification, the following composition :
"` 13~15~3 DP > 2 : 1.3 DP 2 : 5.6 Glycerln : 0.2 Mannltol : 1.O
Other hexitols : 0.4 Sorbltol : 93.5 Reducing sugars : 0.OB
Total sugars : 2.74 determined by the analytical method disclosed in the FOOD
CHEMICAL CODFX, 2nd Edition, page 791.
b) ChromatoqraDhic seParation steD
The above-said hydrogenated starch hydrolysate is then sent to a continuous chromatographic separation ins-tallation of which the details of constitution and of operation are those disclosed 1n US Patent N 4 442 881 and in the corresponding French publication number 2454830 of October 14, 1983, the said details only being taken up again here to the extent that understanding of the present description requires it.
It includes, as shown in Figure 2 of the American patent (taken up again here as Figur 2 for the ôetailed explanation of which reference is made to the American patent), eight columns or stages C1 to CB of 200 liters each, lined with adsorbant of the strong cationic resin type in the calcium form and of fine granulometry (0.2 to 0.4 microns).
By adjustment of the electrovalves, there are formed a desorption zone I of two stages, an adsorptlon zone II of four stages and an enrichment zone III for the hydrogenated polyholosides of two stages.
A c.losing device maintains in the configuration adopted the total fluid-tightness betweeh the zone III, enrichment zone at the end of which are recovered the hy-drogenated polyholosides and the zone I or desorption zone of the sorbitol, at the head of which zone the desorption water is lntroduced.
" 9 1311503 This closing device ensures the direction of passage of the liquid phase over the selective adsorbant and avoids especially contamination of the pure sorbitol by traces of polyholosides, whose migration speed within the resin is largely greater than that of the hydrogenated di- or triholosides.
A kimer ~not shown) adjusted to 2i minutes 50 seconds ensures for the flow rates indicated below a water supply sufficient to carry out de-sugaring of the first stage of the desorption zone, and for the supply of a vo-lume of hydrogenated starch hydrolysate or HSH compatible with the volume of adsorbant and its capacity of absorp-tion, so as to obtain an extraction ratio of the hydroge-nated polyholosides greater than 99/ and an extraction ratio of the sorbitol at least equal to 90'~ of the sorbi-tol present in the supplied hydrogenated hydrolysate.
These proportions are kept constant by adjusting the flow rate of the extraction pump ~not shown) of the adsorbed sorbitol. The outflow of the polyholoside frac-tion is effected at atmospheric pressure and its flowrate, constant, results from the difference between the supply flow rates and the extraction flow rate.
The hydrogenated starch hydrolysate which is introduced into the installation at the head of the adsorption stage, has a dry matter content equal to 64.5/..
The temperature inside the separation columns is kept at about 90-C.
In the schematic diagram of Figure 3 is shown the installation of Figure 2 diagramatically at 202 (the same references denoting the same elements for the common parts as in Figure 1). The chromatography installation includes, in addition to the constituent elements already shown in Figure 1,a pipe 210 for recirculating excess water and a pipe 211, through which are extracted from the circuit the polyholoside fractions of DP > 4 extracted at a very low DM.
10 i 1311503 Supply of the installation with water is effected by a pipe 212.
The arrows borne on the pipes indicate the direc-tion of flow~
The unit operates as follows:
- the hydrogenated starch hydrolysate or HSH intended for chromatographlc fractlonation is led through the pipe 207 at a flow rate of 120 l/hour and has a dry matter content of 64.5'~, 10 - the water is introduced through pipe 212 with a flow rate of 330 l/hour, - the pure sorbitol is recovered through the pipe 208 with a flow rate of 240 l/hour, its content of dry matter being 34,15~, - the total amount of liquids extracted from the ins-tallation 202 is e~tracted with a total flow rate of 386 l/hour, comprising successively, . a fraction of e~cess water of 176 l/hour which is recirculated through the pipe Z10 to the head of the installation, . a polyholoside fraction removed through the pipe 211, whose flow rate is 114 l/hour and the DM
about 1~., . a polyholoside fraction led through the pipe 209 to the hydrolysis installation with a flow rate of 96 l/hour, the content of DM being 3.5/
Analyses of the outflows of sorbitol and of hydro-genated polyholosides are presented in Tables I and II.
ll 131~03 Tlmes Brix DP 2 Glycerin Mannitol Sorbitol ~minutes) / . ...
0 56.50.4 0.3 1.0 98.3 3 47.50.3 0.3 0.9 98.5 6 41.50.3 0.3 0.8 ga-.6 12 27.00.2 0.2 0.5 99.1 21.50.2 0.1 0.5 99.2 18 16.0 _ 0.1 0.4 99.5 21 12.5 _ 0.1 0.3 99.6 23'50" 10.0 _ 0.3 99.7 From examination of Table I, it is seen that sor-bitol has been extracted for 23 minutes 50 seconds with an5 average purity higher than 9BZ and an average content of dry matter of 34.15Z.
The value of the "brix" gives the approximate per-centage of dry matter ; it is determined by the refractive index.
TABLE II
ANALYSIS OF THE POLYHOLOSIDES OUTFLOW
Times Brlx Rotatory DP > 3 DP 3 DP 2 Sorbitol (minutes) (a) D Z Z Z Z
!~ ~n 12 _ ~0.166 +++ ++ +
14 0.7 +0.629 +++ ++ +
16 1.5 +1.038 35.9 30.9 22.610.6 18 2 +1.079 24.0 29.5 33.712.8 2.5 +2.209 21.0 26.0 43.79.3 22 3.4 +2.807 16.1 21.2 53.49.3 ~5 23 50" ~.0 +2.604 13.5 19 D57.0 10.5 12 ' 1 3 il ~ 03 The specific rotatary power (a)D is deduced from theangle of ro-tation read on a polarimeter.
Detailed analysis of the results collected in Table II
and of the indications provided above with respect to Figure 3, as regards the hydrogenated polyholosides, shows in addition that:
- during the first 11 minutes, that is to say an equivalent of 176 l/h, the polyholosides outflow has been recyclable for the de-sugaring of the following stage, - from minute 11 to minute 18, the extracted fraction, containing the major portion of the hydrogenated polyholosides of DP greater than or equal to 4 was elimi-nated from the system, that is to say 114 l/h with 1X of dry matter, - then, from minute 18 to the moment corresponding to Z3 minutes 50 seconds, the polyol fraction was recovered for the hydrolysis step, that is to say 96 liters with a dry matter of 3.6/
The overall balance, which appears on examining the diagram of Figure 3 and Tables I and II, is summarised as indicated below.
The chromatographic separation system was supplied as follows: -Hydrogenated starch Water hydrolysate Flow rate 120 l/h 330 l/h Density 1.269 ~/ dry matter . 64.5 Flow rate by weight 98.22 kg/h There was drawn from this system :
Higher polyols Polyols Sorbitol discarded recovered Flow rate 240 l/h 114 l/h 96 l/h Density 1.138 1.0 1.02 / dry matter 34.15 1.0 3.6 Flow rate by weight 93.27 kg/h 1.14 kg/h 3.53 kg/h `" 1311~0~
These results correspond to an extraction ratio of sorbitol present in the hydrogenated starch hydrolysate - higher than 99~..
c) Continuous hvdrolysis steD of the recovered polvols The fraction of polyols recovered is then led through the pipe 209 into a hydrolysis vessel 203 consti-tuted by a column identical with that equiping the chroma-tographic separation installation illustrated by Figure 2.
This column is filled with a cationic resin of very fine granulometry (U.1 - 0.2 micr~ns) placed in the H form.
- The feed flow rate was adjusted to about 90 liters/
hour.
The hydrolysis vessel was kept at a temperature of about 110-C.
Under these conditions, the hydrolysed syrup flows out from the vessel 203 with a proportion of reducing sugars equal to 17.0 grams/liter glucose equivalent, which is equivalent to a hydrolysis ratio of 91.4-~, since an as-say test of the reducing sugars carried out after complete hydrolysis ~effected after two hours under reflux in the presence of normal H2S0~) showed a glucose equivalent of lB.6 grams per liter.
The chromatographic analyses of the syrup at the inlet and. at the outlet from the hydrolysis vessel 203 gave the results indicated below.
The compcsition of the syrup led through the pipe 209 to the vessel 203 was as follows:
Sorbitol 9 Mannitol 0.8 DP 3 15.2 DP > 3 20 14 ' ~ 3 and that of the syrup emergi.ng from the vessel 203 through the pipe 204b, determined on three samplings, as follows:
Sorbitol 41 42 39.6 Mannitol Z.3 2.5 2.a DP 3 5 6.5 7.0 Glucose 46.4 52 45.6.
dl Recirculation throu~h ~ioe 204b of the svruo thus hvdrolysed to the hvdro~enation vessel 201. which corresPonds to a dilution of the startinq starch hvdrolvsate.
In this case, through the pipe 204 is conducted a starting material constituted by starch hydrolysate not yet treated and hydrolysed syrup emerging from the vessel 15 203.
In Figure 4, are shown diagramatically the princi-pal elements of the corresponding installation, the same elements being denoted by the same reference figures as in Figures 1 and 3.
Two stages of purification 213 and of evaporation purification 214 are shown in respectively the pipes 205 and 207.
To bring the raw material introduced into the vessel 201 to a dry matter content of about 43/., which z5 corresponds to the optimal conditions of the hydrogenation reaction, through the pipe 204a is led, at a flow rate of 140.4 kglh, -the starch hydrolysate not yet treated and having a content of dry matter of 70Z., which, after combi-ning with the flow rate of 97.9 kg/h of syrup flowing from the vessel 203 with a dry matter content of 3.6Z provides a raw material of dry matter content 42.7/. with a flow rate of 23a.3 kg/h.
After purification and evaporation at step 214.
there is thus led to the installation 202, through the pipe 207, a hydrogenated syrup with a dry matter content of 64.5/. at a flow rate of 120 l/h.
' 1311~0~
As already indicated with respect to Figure 3:
- the installation 202 is fed with 330 l/hour of water coming through the pipe 212 to which is added the 176 l/
hour of excess water recycled through the pipe 210, i.e. a total of 506 lthour ;
- from installation 202 is extracted:
. 11`4 l/hour of a fraction of higher polyols removed from the system through the pipe 211 and having a dry matter content of about 1~., 10. 96 l/hour with a dry matter content of 3.6'~ of po-lyols led to the hydrolysis vessel 203 through the pipe 209.
The whole of the device thus described was placed in continuous operation.
15In Tables III, IV and V below, are collected the values recorded respectively with respect to the analyses of the hydrogenated starch hydrolysate before chromatogra-phic separation with the analyses of the sorbitol fraction recovered and with the analyses of the fraction which have to be subjected to hydrolysis, in the course of five different successive samplings.
HYDROGENATED HYDROLYSATE BEFORE CHROMATOGRAPHY
DP > 2 1.6 1.: 1.55 1.5 1.7 DP 2 ~.5 3.5 2.85 3.4 3.6 Glycerin 0.1 0.1 0.2 0.2 0.2 Mannitol 0.7 0.9 1.0 0.8 1.0 Other hexitols 0.3 0.3 0.4 0.2 0.4 SORBITOL 93.8 93.6 93.9 93.9 93.1 Reducing sugars 0.09 0.07 0.065 0.06 0.092 Total sugars 1.5 1.45 1.50 1.33 1.33 T LEAU IV
P > 2 ~ O,z r :~1=0~ 25 '~
SORBITOL 98.6 98.2 98.4 98.~5 98.1 Manni-tol O . r O . 9 O . 9 O . 8 1 . O
Glycerin 0.2 0.2 0.2 O.Z 0.2 Other hexitols 0.3 0.4 0.3 0.3 0.4 Reducing sugars 0.017 0.028 0.010 0.020 0.012 Total sugars 0.11 0.09 0.14 0.12 0.17 ANALYSIS OF THE FRACTION SUBJECTEO TO HYDROLYSIS
DP > 3 20.2 20.2 16.9 16.4 DP 3 ___, 18.4 16.1 14.1 13.8 DP 2 43.2 49.2 55.8 55.5 SORBITOL 17.6 13.5 12.1 13.3 Mannitol 0.6 1.0 1.1 1.0 Other hexitols _ _ _ Reducing sugars 0.83 0.30 0.25 0.35 Total sugars I 26.4 28.0 33.5 30.5 The sorbitol fraction so obtained was compared with five liquid sorbitol grades obtained by hydrogenation of dextrose according to the prior art and of which the analyses are presented in Table VI below:
17 ' 1311~0~
TABLE VI
HYDROGENATION OF DEXTROSE ACCORDING TO THE PRIOR ART
5 DP > 2 ¦ 0.06 0 15 0.40 O Z5 0.30 DP 2 ¦ 0.40 D.40 0.40 0.6 0.50 SORBITOL 97.84 9a.a 97.55 97.35 97.40 Other hexitols 0.40 0.50 0.15 0.2 0.20 10 Mannitol 1-.0 0.80 1.1 1.1 1.1 Glycerin 0.30 0.03 0.4 0.5 0.5 Reducing sugars 0.05a 0.040 0.052 0.047 0.050 15 Total sugars 0.26 0.26 0.22 0.26 0.30 It can be observed, by comparing Tables IV and VI
that the sorbitol quality obtained by the process accor-ding to the invention:
- has a higher average purity in sorbitol, - has a content of products of DP equal or greater than 2 which is distinctly lower, - and has a content of reducing sugars distinctly less (0.017 on the average against 0.050).
A ratio of reducing sugars, so low in the case of the process according to the invention, could only be obtained with great difficulty by direct hydrog0nation.
This ratio would need in fact a degree of hydrogenation of 99.98/., which can only be achieved with greatly prolonged and, consequently, uneconomic hydrogenation periods.
This example discloses the production of pure sor-bitol from a hydrol from a frist crop of crystallation of dextrose, having a true dextrose content equal to 86.7'~.
a) Steo of catalvtlc hydroaenation of the hvdrol The hydrol, obtained after crystallisation from a first crop of dextrose monohydrate, has a dry matter con-~` - 1311503 tent of 74Z and the following composition:
DP > 3 2.7 DP 3. 1.8 DP 2 8.5 S Dextrose a6.70 Fructose 0.3.
After purification and hydrogenation, the composi-tion of the syrup became:
DP > 2 4.6 DP 2 7.5 Glycerin Mannitol 1.0 Other hexitols 0.Z
Sorbitol 86.7.
b) Ste~ of continuous liouid chromatoqraDhic seDaration This separation was carried out on the device and according to the process described in Example 1 with res-pect to Figure 3.
The c.hromatography installation was fed:
- with hydrogenated hydrol through pipe 207 at a flow rate of 120 l/hour, the hydrol having a dry matter of 627. and a density d-1.267, i.e. 94.26 kg/hour, - with water through the pipe 212 at a flow rate of 330 l/hour, - with a fraction of excess water recirculated through the pipe 210 at a flow rate of 176 l/hour.
There was withdrawn from this installation:
- pure sorbitol through the pipe 20a at a flow rate of 220 l/hour, the content of dry matter being 32Z
and the density 1.137, that is to say 80 kg/hour, - a polyol fraction, discarded through the pipe 211, at a flow rate of 100 l/hour, the dry matter content being 1.5Z and the density 1.00, that is to say 1.5 kg/
hour, - a fraction of polyols subjected to hydrolysis i~ll503 through the pipe 209 at a -flow rate of 130 l/hour, with a dry matter content of 8.8Z and a density of 1.02, that is to say 11.7 kg/hour.
The whole gave an extraction calculated on the sorbitol of 96.2Z..
c) Contlnuous hvdrolvsis steP
The streams of recovered polyols were conducted through the pipe 209 to the hydrolysis vessel 203 as descrlbed in Example 1. The temperature is kept at 115 C
in side the said vessel 203. The degree of hydrolysis of the polyholosides measured by the reducing sugars in comparison with the product hydrolysed under reflux for two hours in the presence of normal sulfuric acid, was always higher than 90Z.
d) Dilution steo, bv means of the sVruo flowina from vessel 203 and led throuqh the ~iDe 204b.
of the hvdrol introduced throuqh the ~iPe 204a before Durification In the integrated circuit as presented in Example 1, the hydrolysed polyol fraction was used for the dilu-tion of the hydrol before puriflcation, the whole consti-tuting the raw material subjected to hydrogenation.
From the practical point of view, 112 kg/h of hy-drol with 74/ of dry matter are thus diluted with 130 l/h of the hydrolysed polyols. The solution thus diluted titrates 3f~.7Z of dry matter.
, After hydrogenation, purification and evaporation to 62Z of dry matter, the syrup was sent to the continuous chromatography installation.
-o-0-o-After several days of operation, the results col-lected in Tables VII (for three samplings), VIII lfor five samplings), and IX (for five samplings) were obtained.
` 20 131t5~3 ARLE VII
HYDROL DILUTED BY THE HYDROGENATED POLYHOLOSIDES
HYDROLYSED AND THEN HYDROGENATED
Nature of the Content in l.
constituent ir the syru~
DP > 2 4.6 2.9 5.6 DP 2 7.1 7.5 7.7 1 0 ~
Glycerin 0.1 0.2 0.1 Mannitol 1.1 0.9 1.0 Other hexitols 0.3 0.2 0.3 15 SOROITOL 86.8 88.3 85.3 Reducing sugars 0.08 0.06 0.07 Total sugars 4.36 4.7 5.5 TABLE VIII
Nature of the Content in /.
constituent in the sorbi tol DP 3 _ _ _ _ _ _ 25 DP 2 0.4 0.3 0.6 0.2 0.
Mannitol 1.0 1.1 0.9 0.7 1.1 Other hexitols 0.3 0.2 0.2 0.3 0.1 Glycerin 0.15 0.1 0.1 0.2 0.1 30 SORBITOL ¦ 98.15 98.3 98.2 98.6 98.6 Reducing sugars 0.025 0.010 0.022 0.010 0.040 Total sugars 0.11 0.15 0.20 0.09 0.13 - ~311~3 _BLE IX
ANALYSIS OF THE POLYOLS INTRODUCED BEFORE HYDROLYSIS
Nature of the Content in /.
constituent S
DP > 3 18.7 20.2 21.3 16.9 16.4 DP 3 15.9 16.1 17.0 14.2 13.7 DP 2 48.0 49.2 51.9 55.8 57.4 SORBITOL 17.4 14.5 9.8 13.1 13.5 Reducing sugars 0.17 0.14 0.11 0.14 0.14 Total sugars 27.1 33. a 34.5 29.6 28.7 The more detailed composition of a sample of this polyol fraction before hydrolysis is given in Table X :
TABLE X
Nature of the Content ln /
constituent _ Sorbitol ` 12.8 Mannitol 1.9 DP 2 50.4 DP 3 14.9 DP 4 3.0 DP 5 2.1 DP 6 2.9 DP 10 to DP 20 5.6 DP > 20 0.9 From all these analyses, it again emerges that the quality of sorbitol produced under these conditions with a total yield from a hydrol from a first crystallisation of dextrose is at least equal to that obtained by hydrogena-tion of a pure dextrose.
Reference will be made, by way of comparison, with the compositions, given in Example 1, of sorbitol obtained by dextrose hydrogenation.
i 1311503 T~e polyols extracted throughout the balanced ope-ration of the chromatography had a true sorbitol content less than 15-/., which indicates an effective extraction of the sorbitol, higher than 90Z of the content of sorbitol of the material processed.
This example illustrates the production of pure sorbitol from a H2 hydrol of a second crystallisation crop of dextrose, titrating about 78'Z of true dextrose.
Reference is made again to Figures 1`and 3.
a) Hvdroqenation steo The syrup obtained after purification and hydroge-nation had the composition indicated in Table XI:
Nature of the Content in Z
constituent DP > 3 3.5 DP 3 3.1 DP 2 11.1 - 20 Mannitol 1.0 Other hexitols0.3 Sorbitol 78.0 Reducing sugars 0.48 . Total sugars7.1 z5 b) ChromatoqraPhv steo The above-said syrup was supplied at a flow rate of 103.2 l/h for a content of dry matter of 63.5~/. through pipe 207 to the continuous liquid chromatography installa-tion 202 described previously ; the density of the syrup was 1.264.
The -Feed flow rate of water through the pipe 212 of this installation was 341 l/h, to which must be added a flow rate of 166 l/h of recirculated water (excess water cominq from the total de-sugaring during the preceeding sequence of the first pure sorbitol desorption stage) introduced through the pipe 210.
1311~03 The sorbitol extraction pump was regulated to 200 l/h to obtain at the same time excellent sorbitol quality as well as maximum extraction ratio.
Hence 200 l/h of sorbitol was extracted with a dry matter content of 28A2~.~ namely 62.04 kg/hour through the pipe 208.
Through the pipe 209 was extracted a syrup which had to be subjected to hydrolysis, the flow rate being 134 l/hour, the density 1.04 and the dry matter content 13.7~, namely 18.9 kg/hour.
Through the pipe 211 was extracted a discarded syrup with a flow rate of 160 l/hour, the dry matter con-tent being 1.7'~, namely 1.87 kg/hour.
Analysis was made as a function of time of both te sorbitol extracted from the installation and the output of the polyol fraction.
The results are collected in Tablex XII and XIII.
ANALYSIS OF THE SORBITOL
Tlme 31 iK DP > 3 0P Z Mannitol ~ Sorbitol 0 56 0.2 D.5 1.1 0.3 97.9 2 54 0.2 0.4 1.0 0.3 98.0 4 48 0.2 0.4 1.0 0.4 97.9 6 4.0 0.1 0.3 1.0 0.3 98.1 835.5 0.1 0.2 1.0 0.3 98.4 1 n 31 0.2 1.0 0.3 98.5 12 26 0.2 0.9 0.4 98.5 14 21 0.3 0.9 0.3 98.4 16 16 0.3 0.8 0.3 ~38.6 0.2 0.7 0.3 98.9 22 8 0.2 0.6 0.3 98.9 30 2~ 6 0.2 0.6 0.3 98.9 1311~
TA3lE XIII
ANALYSIS OF THL POLYOLS FRACTION
24 Z3.0 21 16.7 54.6 1.4 0.4 6 c) Continuous hvdrolvsis ste~
The syrup recovered for the purposes of hydrolysis at the outflow of the installation 202 is led to the hy-drolysls vessel as described in Fxample 1.
The temperature therein was kept at 110 C. The degree of hydrolysis of the polyholosides for a flow rate of 130 l/h on a bed of 20 liters of adsorbant was always higher than 907..
The degree of hydrolysis was, as in the preceeding examples, obtained by comparing the ratio of reducing su-gars expressed in glucose equivalents, found in the syrupflowinq out from the hydrolysis vessel, with that found in a specimen subjected to the action of normal sulfuric acid under reflux.
d) steP of dilution of the hydrol H2 introduced throuqh the oioe 204a. before hydroqenation with the svru~ flowinq from the hvdrolvsis vessel and conducted throuah the Pipe 204b.
93.4 kglhour of hydrol H2 with 74/. of dry matter was diluted with 134 l/hour of hydrolysed polyols with 35 13.7/ of dry matter, introduced through the pipe 204b, the solution obtained representing 230 kg/hour of a syrup with about 36/. of dry matter.
1311~03 Tllis syrup was hydrogenated, purified and evapo-rated to 63.5/. of dry matter, then led to the continuous chromatography installation 202.
After several days of operation, analysis was car-ried out of five samplings of the raw material constituted by the hydrol diluted with the syrup introduced through 204b (Table XIV) and hydrogenated, five samplings of the sorbitol obtained ITable XV) and four samplings of the syrup introduced through the pipe 209 (Table XVI).
TABLE XIV
HYDROL DILUTED WITH HYDROGENATED POLYHOLOSIDES
HYDROLYSED AND THEN HYDROGENATED
. _ Nature of the Contents in X
constituent DP > 3 5.2 6.6 4.5 5.4 4.3 _ DF 3 3.3 4.3 3.1 2.8 3.2 DP 2 10.2 14.0 11.7 12.4 11.7 20 Mannitol 1.2 1.3 1.2 1.3 1.5 SORBITOL 79.8 75.4 79.2 79.0 79.0 Other heuitols 0.3 0.4 0.3 0.2 0.3 25 Reducing sugars 0.05 0.045 0.048 0.035 0.07 Total sugars 6.9 7.2 7.5 7.0 8.0 26 ~ 1311~03 TABLE XV
Nature of the Contents in ~.
constituent S _ _ DP 3 _ 0.1 0.05 0.05 0.1 .
DP 2 0.2 0.2 0.2 0.3 0.3 Mannitol 0.9 0.9 1.1 1.1 1.2 Other hexitols 0.5 O.Z 0.2 0.3 0.1 SORBITOL 98.4 98~6 98.45 98.25 98.3 _ . ..
Reducing sugars 0.011 0.027 0.028 0.01 0.03 . _ Total sugars 0.04 0.2 0.12 0.15 0.13 _ . .
Results of analyses collected in Tables XIV and XV, show that the sorbitol quality produced under these conditions from hydrol H2 had a purity at least equal to that obtained by hydrogenation of a pure dextrose and .is characterised by a very low content of reducing sugars.
TABLE XVI
DP > 3 19.2 21.7 21.0 20.7 .
DP 3 15.9 16.9 16.~ 16.4 . .. __ _ DP 2 51.6 56.1 54.6 54.8 _ Mannitol 3 2 1.8 2 _ __ SORBITOL 10 2.9 5.8 5.7 . .
Reducing sugars 0.3 0.4 0.40 0.4 - _ .
Total sugars 35.0 38.2 36.4 32.2 :
From the results collected in Table XVI, it is deduced that the polyols extracted throughout the balanced 27 ' 13~1503 operation of the chromatography installation had a sorbi-tol content below 10~, which indlcated a very efficient extraction of the sorbi-tol, higher than about 9~7. of the content in sorbitol of the raw material.
As is self-evident and as emerges already besides from the foregoing, the invention is in no way limited to the embodiments and applications which have been more par-ticularly envisaged ; it encompasses, on the contrary, all modifications.
PROCESS FOR THE PREPARATION OF VERY HI~H PURITY
SOR~ITOL SYRUPS
5The invention relates to a process for the prepa-ration of very high purity sorbitol syrups.
At the present time, very high purity sorbitol syrups are obtained by hydrogenation of dextrose syrups prepared by dissolving crystalline dextrose in water.
10The richness of sorbitol syrups so obtained which is sufficient, however rarely exceeds 98X after purifica-tion.
The reason therefor is that in addition to traces of hydrogenated polyholosides originating in the raw mate-rial and traces of reducing substances which have escaped the hydrogenation, there are formed during the hydrogena-tion, isomers of sorbitol, namely particularly mannitol.
The presence of this group of products results in certain drawbacks in the matter of crystallisation operations of the sorbitol from these syrups and has consequences on the characteristics of the crystalline sorbitol obtained, par-ticularly from the point of view of its crystallinity.
In addition, the yield of the operation is not entirely satisfactory since, to obtain sorbitol syrups ha-ving this richness, which in any case rarely exceeds 98X,it is necessary to satisfy oneself with limited yields at the level of the preceding step of preparation of the crystalline dextrose, which is used for the preparation of the subsequently hydrogenated dextrose syrup, and which is obtained by crystallisation in two or three crops from starch hydrolysates with a glucose content of the order of 94 to 96/. by weight ; in fact, said yields of dextrose are generally limited to about 75 to 77/. in two crops and to about 80 to 88/. after a third crop and the crystallisation mother liquors or hydrols have a sometimes difficult sale in commerce by reason of their color and their content of . .
- i' " 1311~03 impurities.
It has indeed already been proposed to suppress the intermediate crystallisation step of the dextrose by subjecting directly, within the same reaction vessel, a cheaper raw material, namely a starch hydrolysate, not only to reducing c:onditions, but also to hydrolysis by means of a strong acid, which permits also to make use of the conversion known in itself, of polyholosides such as maltitol or isomaltitol into equimolecular amounts of sorbltol and of glucose under the action of the strong acid.
It is possible to mention in this respect French Patent N 1 263 290 which proposes the use, as a catalyst, of reduced nickel on a support constituted of infusorial earth and according to which there is carried out in one and the same reaction vessel, in substantially neutral solution and at a moderately high temperature, a reduction of the major part of the reducing sugars, after which a strong inorganic acid such as phosphoric acid is added, in 20. a proportion of 0.05 to 1.0~ by weight on the basis of the saccharides initially employed, the mixture constituted by the thus acidified solution and the catalyst being sub-jected to higher pressure and temperature, by means of which the hydrolysis of the hydrogenated polyholosides present in the hyd.rolysate and the hydrogenation of the sugars then appearing are effected simultaneously.
Within the same order of ideas, but 15 years later, Belgian Patent N ~37 201 described the simulta-neous hydrogenation-hydrolysis-hydrogenation of starch hydrolysates with use of a ruthenium catalyst supported on zeolite of type Y; the hydrogenation reaction is effected in two steps, the first being conducted at a temperature comprised between 100 and 175 C and the second at a tempe-rature of about 170 to 200-C. The pH conditions in which the consecutive phases of the hydrogenation take place are specified, the pH of the product of the reaction having to 13~1503 be comprised between 3.5 and 4.
The drawbacks of these processes reside not only in the rapid deactivation of the catalysts and in the de-naturation of the structure of the zeolites, but also in S the fact that the syrups so obtained include numerous impurities.
Thus, - there occur partial anhydrysation reaction and isomerisation of the polyols, - the hydrolysis of the hydrogenated polyholoside fraction is incomplete and manifested by a high value of "total sugars", - the proportions of "hexitans", of mannitol, of "total non-sugar impurities" are large, the content of true sorbitol being finally at the most equal to 94X, which is, for example, very insufficient for the prepara-tion of a crystalline sorbitol of suitable quality.
Another process suitable for the preparation of sorbitol syrup without passage through the crystallisation of the dextrose is that described in French Patent N-2 052 202 filed by the Assignee. According to this pro-cess, in which recourse is also had, as starting material, to a starch hydrolysate which is hydrogenated, a fractio-nation of the hydrogenated starch hydrolysate is carried out by passage over a resin or a cationic molecular sieve, preferably in calciurn form, which permits the isolation of a fraction containing sorbitol of richness greater than 99Z .
This technique therefore leads to a sorbitol of very high purity, but it proves however to be unsatisfac-tory in practice. It results, in fact, in a very partial yield of sorbitol, strictly dependant on the true dextrose content of the starting starch hydrolysate, the latter having for this reason to be as high as possible.
It follows that a priori none of the known proces-ses permits at the same time the manufacture of sorbitol 131~503 syrup of high purity, suitable particularly for the preparation of crystalline sorbitol, and an easy access to high yield whose influence on the cost price of the final product is readily seen.
It is to this problem that the Applicants have had the merit of proposing a particularly effective solution, according to which a raw material of which a first part is constituted by a starch hydrolysate, is subjected to a process comprising in combination - a catalytic hydrogenation step of the raw material, - a step of chromatographic separation of the raw material which has undergone hydrogenation into a first fraction containing very pure sorbitol and which is recovered and into a second fraction containing, besides sorbitol, non-hydrogenated sugars as well as hydrogenated di- and polysaccharides, - an acid hydrolysis step of the abovesaid second fraction, which provides a partially hydrogenated starch hydrolysate which is recycled and which constitutes a second part of the raw material subjected to the hyrogenation step.
IN THE DRAWINGS
Figure 1 is a diagrammatic flow sheet illustrating an installation for carrying out the process in accordance with the invention;
~, -4a- ~ 3 ~ 1~ a 3 Figure 2 is a diagrammatic view of an installation suitable for carryi.ng out the chromatographic fractionation step in accordance with the invention;
Figures 3 and 4 are diagrammatic flow sheets representing particular embodiments of the installation proper to carry out the process in accordance with the invention.
The process thus defined may be carried out by means of the installation shown diagrammatically in Figure 1 and which comprises:
- a vessel 201 within which the catalytic hydrogenation step is carried out, - a chromatographic separation installation 202 and - a reaction vessel 203 within which the hydrolysis step is carried out.
The vessel 201 is supplied with raw material. through a pipe 204 formed by the junction at 205 of a pipe 204a bringing in the starch hydrolysate from a tank (not shown) and a pipe 204b connected to the outlet of the vessel 203 and introducing the partially hydrogenated 1~115~
hydrolysate.
The outlet of the vessel 201 is connected to the inlet of the vessel 202 through a pipe 207.
From the outlet of the ~essel 20Z, are conducted :
- the first fraction containing very pure sorbitol through a pipe 208 to a storage tank Inot shown) and - the second fraction containing sorbitol, non-hydrogenated sugars as well as hydrogenated di- and poly-saccharides through a pipe 209 to the inlet of the vessel 10 203.
The means proper to ensure the circulation of the various syrups within the installation are not shown.
The starch hydrolysate which is part of the c~ons-titution of the raw material has, preferably, a true dextrose content comprised between 65 and 97X and, more preferably still, between 70 and 95~/.. Particularly advan-tageous starch hydrolysates are constituted by hydrols of the first and of the second crop obtained in the crystal-lisation of the dextrose.
In the foregoing and in the following, the percen-tages indicated are understood, except when stated to the contrary, with respect to the dry matter of the syrups.
The catalytic hydrogenation step is carried out in manner known in itself, particularly on ruthenium or Raney nickel catalysts. Preferably, it is carried out on a Raney nickel catalyst, at a hydrogen pressure comprised between 40 and 70 kg/cm and at a temperature of about 100 to 150 C.
The chromatographic separation step can be effect-ed, in manner known in itself, discontinously or conti-nuously Isimulated mobile bed), on strongly acid absor-bants of the cationic resin type, charged with alkaline or alkaline earth ions or of the zeolite type, charged with ammonium, sodium, potassium calcium, strontium, or barium ions.
Examples of such chromotographic separation pro-cesses are described in patents US 3 044 904, US 3 416 961, 6 1 3 ~ 3 US 3 692 582, FR 2 391 754, FR 2 099 336, US 2 985 589, US
02~ 331, US 4 226 977, US ~ 293 346, US 4 157 267, US
1~2 633, US ~ 332 633, US 4 405 4~5, US4 ~12 866, and US
4 4~2 ~381.
In a preferred embodiment, the chromatographic se-paration step lS carried out by employing the process and the lnstallation dlsclosed in US Patent N- 4 ~42 881 and its corresponding French Application N 79 10563, published October 14, 1983 under publication no. 2454830.
Whatever the chromatographic separation process adopted, recourse is had, preferably, as adsorbant, to a strong cationic resin placed in the calcium form and hav-ing a proportion of divinyl-benzene from about 4 to about 1 0 1. .
Preferably, the acid hydrolysls step of the above-said second fraction is carried out on a fixed acid cata-lyst and it is conducted so that more than ~OX by weight of the hydrogenated disaccharides and polysaccharides present are hydrolysed.
It is possible to use, to do this, any type of reaction vessel and any reagent or acid catalysts capable of ensuring the hydrolysis of hydrogenated disaccharides and polysaccharides.
Preferably, said hydrolysis is carried out conti-nuously by passing the syrup containing the polyols to be hydrolysed over a fixed bed comprising acid catalysts of the alumino-silicate, silica, alumina or cationic resin type, at a temperature and for a time sufficient to achieve the above indicated desired result.
3n Advantageously, the hydrolysis is conducted on strong cationic resins in the acid form, at a temperature comprised between 50 and 120 C, the passage flow rate over the acid catalyst bed being regulated so as to obtain a hydrolysis ratio of the hydrogenated di- and polysacchari-des at~least equal to 60l. and, preferably, at least equal to 80/..
~'~
``"` 13i 1503 The content of dry matter of the above-said second fraction which is subjected to the hydrolysis step and which is recycled is generally comprised between 1.5~. and 30~ and, preferably, between 2.5 and 20'~.
The process thus described permits sorbitol syrups to be obtained having a richness in sorbitol greater than 9~/., and even greater than 997., which are essentially cha-racterlsed by a minimal content of reducing sugars. These syrups, which have at the outlet from the vessel 202, a content of dry matter comprised between 20~/. and 50'~ and, preferably between 25~/. and 40~, can then be evaporated to the dry matter content for marketing or be evaporated more completely for the production of crystalline sorbitol.
The invention will be still better understood by means of the examples which follow and of the illustrative figures appended hereto, said e~amples relating to prefer-red embodiments of the invention.
Preparation of pure sorbitol from a starch hydrolysate prepared by a double enzymatic hydrolysis with -amylase and amyloglucosidase and having a richness in true dex-trose equal to 94.5~/., its composition being :
Dry Matter (DM) : 74.0 ~/.
De~trose : 94.5 ~/.
Z5 DP 2 : 4.0 DP 3 : 1.0 DP > 3 : o.s it being understood that "DP" means the degree of polyme-risation of a given constituent of the hydrolysate.
a~ Hvdroqenation ste~
The above-said hydrolysate, after purification on ion exchange resins and on active carbon, is hydrogenated on Raney nickel,~at a hydrogen pressure of 45 kg/cm and at a temperature of 125'C.
It shows, after conventional purification, the following composition :
"` 13~15~3 DP > 2 : 1.3 DP 2 : 5.6 Glycerln : 0.2 Mannltol : 1.O
Other hexitols : 0.4 Sorbltol : 93.5 Reducing sugars : 0.OB
Total sugars : 2.74 determined by the analytical method disclosed in the FOOD
CHEMICAL CODFX, 2nd Edition, page 791.
b) ChromatoqraDhic seParation steD
The above-said hydrogenated starch hydrolysate is then sent to a continuous chromatographic separation ins-tallation of which the details of constitution and of operation are those disclosed 1n US Patent N 4 442 881 and in the corresponding French publication number 2454830 of October 14, 1983, the said details only being taken up again here to the extent that understanding of the present description requires it.
It includes, as shown in Figure 2 of the American patent (taken up again here as Figur 2 for the ôetailed explanation of which reference is made to the American patent), eight columns or stages C1 to CB of 200 liters each, lined with adsorbant of the strong cationic resin type in the calcium form and of fine granulometry (0.2 to 0.4 microns).
By adjustment of the electrovalves, there are formed a desorption zone I of two stages, an adsorptlon zone II of four stages and an enrichment zone III for the hydrogenated polyholosides of two stages.
A c.losing device maintains in the configuration adopted the total fluid-tightness betweeh the zone III, enrichment zone at the end of which are recovered the hy-drogenated polyholosides and the zone I or desorption zone of the sorbitol, at the head of which zone the desorption water is lntroduced.
" 9 1311503 This closing device ensures the direction of passage of the liquid phase over the selective adsorbant and avoids especially contamination of the pure sorbitol by traces of polyholosides, whose migration speed within the resin is largely greater than that of the hydrogenated di- or triholosides.
A kimer ~not shown) adjusted to 2i minutes 50 seconds ensures for the flow rates indicated below a water supply sufficient to carry out de-sugaring of the first stage of the desorption zone, and for the supply of a vo-lume of hydrogenated starch hydrolysate or HSH compatible with the volume of adsorbant and its capacity of absorp-tion, so as to obtain an extraction ratio of the hydroge-nated polyholosides greater than 99/ and an extraction ratio of the sorbitol at least equal to 90'~ of the sorbi-tol present in the supplied hydrogenated hydrolysate.
These proportions are kept constant by adjusting the flow rate of the extraction pump ~not shown) of the adsorbed sorbitol. The outflow of the polyholoside frac-tion is effected at atmospheric pressure and its flowrate, constant, results from the difference between the supply flow rates and the extraction flow rate.
The hydrogenated starch hydrolysate which is introduced into the installation at the head of the adsorption stage, has a dry matter content equal to 64.5/..
The temperature inside the separation columns is kept at about 90-C.
In the schematic diagram of Figure 3 is shown the installation of Figure 2 diagramatically at 202 (the same references denoting the same elements for the common parts as in Figure 1). The chromatography installation includes, in addition to the constituent elements already shown in Figure 1,a pipe 210 for recirculating excess water and a pipe 211, through which are extracted from the circuit the polyholoside fractions of DP > 4 extracted at a very low DM.
10 i 1311503 Supply of the installation with water is effected by a pipe 212.
The arrows borne on the pipes indicate the direc-tion of flow~
The unit operates as follows:
- the hydrogenated starch hydrolysate or HSH intended for chromatographlc fractlonation is led through the pipe 207 at a flow rate of 120 l/hour and has a dry matter content of 64.5'~, 10 - the water is introduced through pipe 212 with a flow rate of 330 l/hour, - the pure sorbitol is recovered through the pipe 208 with a flow rate of 240 l/hour, its content of dry matter being 34,15~, - the total amount of liquids extracted from the ins-tallation 202 is e~tracted with a total flow rate of 386 l/hour, comprising successively, . a fraction of e~cess water of 176 l/hour which is recirculated through the pipe Z10 to the head of the installation, . a polyholoside fraction removed through the pipe 211, whose flow rate is 114 l/hour and the DM
about 1~., . a polyholoside fraction led through the pipe 209 to the hydrolysis installation with a flow rate of 96 l/hour, the content of DM being 3.5/
Analyses of the outflows of sorbitol and of hydro-genated polyholosides are presented in Tables I and II.
ll 131~03 Tlmes Brix DP 2 Glycerin Mannitol Sorbitol ~minutes) / . ...
0 56.50.4 0.3 1.0 98.3 3 47.50.3 0.3 0.9 98.5 6 41.50.3 0.3 0.8 ga-.6 12 27.00.2 0.2 0.5 99.1 21.50.2 0.1 0.5 99.2 18 16.0 _ 0.1 0.4 99.5 21 12.5 _ 0.1 0.3 99.6 23'50" 10.0 _ 0.3 99.7 From examination of Table I, it is seen that sor-bitol has been extracted for 23 minutes 50 seconds with an5 average purity higher than 9BZ and an average content of dry matter of 34.15Z.
The value of the "brix" gives the approximate per-centage of dry matter ; it is determined by the refractive index.
TABLE II
ANALYSIS OF THE POLYHOLOSIDES OUTFLOW
Times Brlx Rotatory DP > 3 DP 3 DP 2 Sorbitol (minutes) (a) D Z Z Z Z
!~ ~n 12 _ ~0.166 +++ ++ +
14 0.7 +0.629 +++ ++ +
16 1.5 +1.038 35.9 30.9 22.610.6 18 2 +1.079 24.0 29.5 33.712.8 2.5 +2.209 21.0 26.0 43.79.3 22 3.4 +2.807 16.1 21.2 53.49.3 ~5 23 50" ~.0 +2.604 13.5 19 D57.0 10.5 12 ' 1 3 il ~ 03 The specific rotatary power (a)D is deduced from theangle of ro-tation read on a polarimeter.
Detailed analysis of the results collected in Table II
and of the indications provided above with respect to Figure 3, as regards the hydrogenated polyholosides, shows in addition that:
- during the first 11 minutes, that is to say an equivalent of 176 l/h, the polyholosides outflow has been recyclable for the de-sugaring of the following stage, - from minute 11 to minute 18, the extracted fraction, containing the major portion of the hydrogenated polyholosides of DP greater than or equal to 4 was elimi-nated from the system, that is to say 114 l/h with 1X of dry matter, - then, from minute 18 to the moment corresponding to Z3 minutes 50 seconds, the polyol fraction was recovered for the hydrolysis step, that is to say 96 liters with a dry matter of 3.6/
The overall balance, which appears on examining the diagram of Figure 3 and Tables I and II, is summarised as indicated below.
The chromatographic separation system was supplied as follows: -Hydrogenated starch Water hydrolysate Flow rate 120 l/h 330 l/h Density 1.269 ~/ dry matter . 64.5 Flow rate by weight 98.22 kg/h There was drawn from this system :
Higher polyols Polyols Sorbitol discarded recovered Flow rate 240 l/h 114 l/h 96 l/h Density 1.138 1.0 1.02 / dry matter 34.15 1.0 3.6 Flow rate by weight 93.27 kg/h 1.14 kg/h 3.53 kg/h `" 1311~0~
These results correspond to an extraction ratio of sorbitol present in the hydrogenated starch hydrolysate - higher than 99~..
c) Continuous hvdrolysis steD of the recovered polvols The fraction of polyols recovered is then led through the pipe 209 into a hydrolysis vessel 203 consti-tuted by a column identical with that equiping the chroma-tographic separation installation illustrated by Figure 2.
This column is filled with a cationic resin of very fine granulometry (U.1 - 0.2 micr~ns) placed in the H form.
- The feed flow rate was adjusted to about 90 liters/
hour.
The hydrolysis vessel was kept at a temperature of about 110-C.
Under these conditions, the hydrolysed syrup flows out from the vessel 203 with a proportion of reducing sugars equal to 17.0 grams/liter glucose equivalent, which is equivalent to a hydrolysis ratio of 91.4-~, since an as-say test of the reducing sugars carried out after complete hydrolysis ~effected after two hours under reflux in the presence of normal H2S0~) showed a glucose equivalent of lB.6 grams per liter.
The chromatographic analyses of the syrup at the inlet and. at the outlet from the hydrolysis vessel 203 gave the results indicated below.
The compcsition of the syrup led through the pipe 209 to the vessel 203 was as follows:
Sorbitol 9 Mannitol 0.8 DP 3 15.2 DP > 3 20 14 ' ~ 3 and that of the syrup emergi.ng from the vessel 203 through the pipe 204b, determined on three samplings, as follows:
Sorbitol 41 42 39.6 Mannitol Z.3 2.5 2.a DP 3 5 6.5 7.0 Glucose 46.4 52 45.6.
dl Recirculation throu~h ~ioe 204b of the svruo thus hvdrolysed to the hvdro~enation vessel 201. which corresPonds to a dilution of the startinq starch hvdrolvsate.
In this case, through the pipe 204 is conducted a starting material constituted by starch hydrolysate not yet treated and hydrolysed syrup emerging from the vessel 15 203.
In Figure 4, are shown diagramatically the princi-pal elements of the corresponding installation, the same elements being denoted by the same reference figures as in Figures 1 and 3.
Two stages of purification 213 and of evaporation purification 214 are shown in respectively the pipes 205 and 207.
To bring the raw material introduced into the vessel 201 to a dry matter content of about 43/., which z5 corresponds to the optimal conditions of the hydrogenation reaction, through the pipe 204a is led, at a flow rate of 140.4 kglh, -the starch hydrolysate not yet treated and having a content of dry matter of 70Z., which, after combi-ning with the flow rate of 97.9 kg/h of syrup flowing from the vessel 203 with a dry matter content of 3.6Z provides a raw material of dry matter content 42.7/. with a flow rate of 23a.3 kg/h.
After purification and evaporation at step 214.
there is thus led to the installation 202, through the pipe 207, a hydrogenated syrup with a dry matter content of 64.5/. at a flow rate of 120 l/h.
' 1311~0~
As already indicated with respect to Figure 3:
- the installation 202 is fed with 330 l/hour of water coming through the pipe 212 to which is added the 176 l/
hour of excess water recycled through the pipe 210, i.e. a total of 506 lthour ;
- from installation 202 is extracted:
. 11`4 l/hour of a fraction of higher polyols removed from the system through the pipe 211 and having a dry matter content of about 1~., 10. 96 l/hour with a dry matter content of 3.6'~ of po-lyols led to the hydrolysis vessel 203 through the pipe 209.
The whole of the device thus described was placed in continuous operation.
15In Tables III, IV and V below, are collected the values recorded respectively with respect to the analyses of the hydrogenated starch hydrolysate before chromatogra-phic separation with the analyses of the sorbitol fraction recovered and with the analyses of the fraction which have to be subjected to hydrolysis, in the course of five different successive samplings.
HYDROGENATED HYDROLYSATE BEFORE CHROMATOGRAPHY
DP > 2 1.6 1.: 1.55 1.5 1.7 DP 2 ~.5 3.5 2.85 3.4 3.6 Glycerin 0.1 0.1 0.2 0.2 0.2 Mannitol 0.7 0.9 1.0 0.8 1.0 Other hexitols 0.3 0.3 0.4 0.2 0.4 SORBITOL 93.8 93.6 93.9 93.9 93.1 Reducing sugars 0.09 0.07 0.065 0.06 0.092 Total sugars 1.5 1.45 1.50 1.33 1.33 T LEAU IV
P > 2 ~ O,z r :~1=0~ 25 '~
SORBITOL 98.6 98.2 98.4 98.~5 98.1 Manni-tol O . r O . 9 O . 9 O . 8 1 . O
Glycerin 0.2 0.2 0.2 O.Z 0.2 Other hexitols 0.3 0.4 0.3 0.3 0.4 Reducing sugars 0.017 0.028 0.010 0.020 0.012 Total sugars 0.11 0.09 0.14 0.12 0.17 ANALYSIS OF THE FRACTION SUBJECTEO TO HYDROLYSIS
DP > 3 20.2 20.2 16.9 16.4 DP 3 ___, 18.4 16.1 14.1 13.8 DP 2 43.2 49.2 55.8 55.5 SORBITOL 17.6 13.5 12.1 13.3 Mannitol 0.6 1.0 1.1 1.0 Other hexitols _ _ _ Reducing sugars 0.83 0.30 0.25 0.35 Total sugars I 26.4 28.0 33.5 30.5 The sorbitol fraction so obtained was compared with five liquid sorbitol grades obtained by hydrogenation of dextrose according to the prior art and of which the analyses are presented in Table VI below:
17 ' 1311~0~
TABLE VI
HYDROGENATION OF DEXTROSE ACCORDING TO THE PRIOR ART
5 DP > 2 ¦ 0.06 0 15 0.40 O Z5 0.30 DP 2 ¦ 0.40 D.40 0.40 0.6 0.50 SORBITOL 97.84 9a.a 97.55 97.35 97.40 Other hexitols 0.40 0.50 0.15 0.2 0.20 10 Mannitol 1-.0 0.80 1.1 1.1 1.1 Glycerin 0.30 0.03 0.4 0.5 0.5 Reducing sugars 0.05a 0.040 0.052 0.047 0.050 15 Total sugars 0.26 0.26 0.22 0.26 0.30 It can be observed, by comparing Tables IV and VI
that the sorbitol quality obtained by the process accor-ding to the invention:
- has a higher average purity in sorbitol, - has a content of products of DP equal or greater than 2 which is distinctly lower, - and has a content of reducing sugars distinctly less (0.017 on the average against 0.050).
A ratio of reducing sugars, so low in the case of the process according to the invention, could only be obtained with great difficulty by direct hydrog0nation.
This ratio would need in fact a degree of hydrogenation of 99.98/., which can only be achieved with greatly prolonged and, consequently, uneconomic hydrogenation periods.
This example discloses the production of pure sor-bitol from a hydrol from a frist crop of crystallation of dextrose, having a true dextrose content equal to 86.7'~.
a) Steo of catalvtlc hydroaenation of the hvdrol The hydrol, obtained after crystallisation from a first crop of dextrose monohydrate, has a dry matter con-~` - 1311503 tent of 74Z and the following composition:
DP > 3 2.7 DP 3. 1.8 DP 2 8.5 S Dextrose a6.70 Fructose 0.3.
After purification and hydrogenation, the composi-tion of the syrup became:
DP > 2 4.6 DP 2 7.5 Glycerin Mannitol 1.0 Other hexitols 0.Z
Sorbitol 86.7.
b) Ste~ of continuous liouid chromatoqraDhic seDaration This separation was carried out on the device and according to the process described in Example 1 with res-pect to Figure 3.
The c.hromatography installation was fed:
- with hydrogenated hydrol through pipe 207 at a flow rate of 120 l/hour, the hydrol having a dry matter of 627. and a density d-1.267, i.e. 94.26 kg/hour, - with water through the pipe 212 at a flow rate of 330 l/hour, - with a fraction of excess water recirculated through the pipe 210 at a flow rate of 176 l/hour.
There was withdrawn from this installation:
- pure sorbitol through the pipe 20a at a flow rate of 220 l/hour, the content of dry matter being 32Z
and the density 1.137, that is to say 80 kg/hour, - a polyol fraction, discarded through the pipe 211, at a flow rate of 100 l/hour, the dry matter content being 1.5Z and the density 1.00, that is to say 1.5 kg/
hour, - a fraction of polyols subjected to hydrolysis i~ll503 through the pipe 209 at a -flow rate of 130 l/hour, with a dry matter content of 8.8Z and a density of 1.02, that is to say 11.7 kg/hour.
The whole gave an extraction calculated on the sorbitol of 96.2Z..
c) Contlnuous hvdrolvsis steP
The streams of recovered polyols were conducted through the pipe 209 to the hydrolysis vessel 203 as descrlbed in Example 1. The temperature is kept at 115 C
in side the said vessel 203. The degree of hydrolysis of the polyholosides measured by the reducing sugars in comparison with the product hydrolysed under reflux for two hours in the presence of normal sulfuric acid, was always higher than 90Z.
d) Dilution steo, bv means of the sVruo flowina from vessel 203 and led throuqh the ~iDe 204b.
of the hvdrol introduced throuqh the ~iPe 204a before Durification In the integrated circuit as presented in Example 1, the hydrolysed polyol fraction was used for the dilu-tion of the hydrol before puriflcation, the whole consti-tuting the raw material subjected to hydrogenation.
From the practical point of view, 112 kg/h of hy-drol with 74/ of dry matter are thus diluted with 130 l/h of the hydrolysed polyols. The solution thus diluted titrates 3f~.7Z of dry matter.
, After hydrogenation, purification and evaporation to 62Z of dry matter, the syrup was sent to the continuous chromatography installation.
-o-0-o-After several days of operation, the results col-lected in Tables VII (for three samplings), VIII lfor five samplings), and IX (for five samplings) were obtained.
` 20 131t5~3 ARLE VII
HYDROL DILUTED BY THE HYDROGENATED POLYHOLOSIDES
HYDROLYSED AND THEN HYDROGENATED
Nature of the Content in l.
constituent ir the syru~
DP > 2 4.6 2.9 5.6 DP 2 7.1 7.5 7.7 1 0 ~
Glycerin 0.1 0.2 0.1 Mannitol 1.1 0.9 1.0 Other hexitols 0.3 0.2 0.3 15 SOROITOL 86.8 88.3 85.3 Reducing sugars 0.08 0.06 0.07 Total sugars 4.36 4.7 5.5 TABLE VIII
Nature of the Content in /.
constituent in the sorbi tol DP 3 _ _ _ _ _ _ 25 DP 2 0.4 0.3 0.6 0.2 0.
Mannitol 1.0 1.1 0.9 0.7 1.1 Other hexitols 0.3 0.2 0.2 0.3 0.1 Glycerin 0.15 0.1 0.1 0.2 0.1 30 SORBITOL ¦ 98.15 98.3 98.2 98.6 98.6 Reducing sugars 0.025 0.010 0.022 0.010 0.040 Total sugars 0.11 0.15 0.20 0.09 0.13 - ~311~3 _BLE IX
ANALYSIS OF THE POLYOLS INTRODUCED BEFORE HYDROLYSIS
Nature of the Content in /.
constituent S
DP > 3 18.7 20.2 21.3 16.9 16.4 DP 3 15.9 16.1 17.0 14.2 13.7 DP 2 48.0 49.2 51.9 55.8 57.4 SORBITOL 17.4 14.5 9.8 13.1 13.5 Reducing sugars 0.17 0.14 0.11 0.14 0.14 Total sugars 27.1 33. a 34.5 29.6 28.7 The more detailed composition of a sample of this polyol fraction before hydrolysis is given in Table X :
TABLE X
Nature of the Content ln /
constituent _ Sorbitol ` 12.8 Mannitol 1.9 DP 2 50.4 DP 3 14.9 DP 4 3.0 DP 5 2.1 DP 6 2.9 DP 10 to DP 20 5.6 DP > 20 0.9 From all these analyses, it again emerges that the quality of sorbitol produced under these conditions with a total yield from a hydrol from a first crystallisation of dextrose is at least equal to that obtained by hydrogena-tion of a pure dextrose.
Reference will be made, by way of comparison, with the compositions, given in Example 1, of sorbitol obtained by dextrose hydrogenation.
i 1311503 T~e polyols extracted throughout the balanced ope-ration of the chromatography had a true sorbitol content less than 15-/., which indicates an effective extraction of the sorbitol, higher than 90Z of the content of sorbitol of the material processed.
This example illustrates the production of pure sorbitol from a H2 hydrol of a second crystallisation crop of dextrose, titrating about 78'Z of true dextrose.
Reference is made again to Figures 1`and 3.
a) Hvdroqenation steo The syrup obtained after purification and hydroge-nation had the composition indicated in Table XI:
Nature of the Content in Z
constituent DP > 3 3.5 DP 3 3.1 DP 2 11.1 - 20 Mannitol 1.0 Other hexitols0.3 Sorbitol 78.0 Reducing sugars 0.48 . Total sugars7.1 z5 b) ChromatoqraPhv steo The above-said syrup was supplied at a flow rate of 103.2 l/h for a content of dry matter of 63.5~/. through pipe 207 to the continuous liquid chromatography installa-tion 202 described previously ; the density of the syrup was 1.264.
The -Feed flow rate of water through the pipe 212 of this installation was 341 l/h, to which must be added a flow rate of 166 l/h of recirculated water (excess water cominq from the total de-sugaring during the preceeding sequence of the first pure sorbitol desorption stage) introduced through the pipe 210.
1311~03 The sorbitol extraction pump was regulated to 200 l/h to obtain at the same time excellent sorbitol quality as well as maximum extraction ratio.
Hence 200 l/h of sorbitol was extracted with a dry matter content of 28A2~.~ namely 62.04 kg/hour through the pipe 208.
Through the pipe 209 was extracted a syrup which had to be subjected to hydrolysis, the flow rate being 134 l/hour, the density 1.04 and the dry matter content 13.7~, namely 18.9 kg/hour.
Through the pipe 211 was extracted a discarded syrup with a flow rate of 160 l/hour, the dry matter con-tent being 1.7'~, namely 1.87 kg/hour.
Analysis was made as a function of time of both te sorbitol extracted from the installation and the output of the polyol fraction.
The results are collected in Tablex XII and XIII.
ANALYSIS OF THE SORBITOL
Tlme 31 iK DP > 3 0P Z Mannitol ~ Sorbitol 0 56 0.2 D.5 1.1 0.3 97.9 2 54 0.2 0.4 1.0 0.3 98.0 4 48 0.2 0.4 1.0 0.4 97.9 6 4.0 0.1 0.3 1.0 0.3 98.1 835.5 0.1 0.2 1.0 0.3 98.4 1 n 31 0.2 1.0 0.3 98.5 12 26 0.2 0.9 0.4 98.5 14 21 0.3 0.9 0.3 98.4 16 16 0.3 0.8 0.3 ~38.6 0.2 0.7 0.3 98.9 22 8 0.2 0.6 0.3 98.9 30 2~ 6 0.2 0.6 0.3 98.9 1311~
TA3lE XIII
ANALYSIS OF THL POLYOLS FRACTION
24 Z3.0 21 16.7 54.6 1.4 0.4 6 c) Continuous hvdrolvsis ste~
The syrup recovered for the purposes of hydrolysis at the outflow of the installation 202 is led to the hy-drolysls vessel as described in Fxample 1.
The temperature therein was kept at 110 C. The degree of hydrolysis of the polyholosides for a flow rate of 130 l/h on a bed of 20 liters of adsorbant was always higher than 907..
The degree of hydrolysis was, as in the preceeding examples, obtained by comparing the ratio of reducing su-gars expressed in glucose equivalents, found in the syrupflowinq out from the hydrolysis vessel, with that found in a specimen subjected to the action of normal sulfuric acid under reflux.
d) steP of dilution of the hydrol H2 introduced throuqh the oioe 204a. before hydroqenation with the svru~ flowinq from the hvdrolvsis vessel and conducted throuah the Pipe 204b.
93.4 kglhour of hydrol H2 with 74/. of dry matter was diluted with 134 l/hour of hydrolysed polyols with 35 13.7/ of dry matter, introduced through the pipe 204b, the solution obtained representing 230 kg/hour of a syrup with about 36/. of dry matter.
1311~03 Tllis syrup was hydrogenated, purified and evapo-rated to 63.5/. of dry matter, then led to the continuous chromatography installation 202.
After several days of operation, analysis was car-ried out of five samplings of the raw material constituted by the hydrol diluted with the syrup introduced through 204b (Table XIV) and hydrogenated, five samplings of the sorbitol obtained ITable XV) and four samplings of the syrup introduced through the pipe 209 (Table XVI).
TABLE XIV
HYDROL DILUTED WITH HYDROGENATED POLYHOLOSIDES
HYDROLYSED AND THEN HYDROGENATED
. _ Nature of the Contents in X
constituent DP > 3 5.2 6.6 4.5 5.4 4.3 _ DF 3 3.3 4.3 3.1 2.8 3.2 DP 2 10.2 14.0 11.7 12.4 11.7 20 Mannitol 1.2 1.3 1.2 1.3 1.5 SORBITOL 79.8 75.4 79.2 79.0 79.0 Other heuitols 0.3 0.4 0.3 0.2 0.3 25 Reducing sugars 0.05 0.045 0.048 0.035 0.07 Total sugars 6.9 7.2 7.5 7.0 8.0 26 ~ 1311~03 TABLE XV
Nature of the Contents in ~.
constituent S _ _ DP 3 _ 0.1 0.05 0.05 0.1 .
DP 2 0.2 0.2 0.2 0.3 0.3 Mannitol 0.9 0.9 1.1 1.1 1.2 Other hexitols 0.5 O.Z 0.2 0.3 0.1 SORBITOL 98.4 98~6 98.45 98.25 98.3 _ . ..
Reducing sugars 0.011 0.027 0.028 0.01 0.03 . _ Total sugars 0.04 0.2 0.12 0.15 0.13 _ . .
Results of analyses collected in Tables XIV and XV, show that the sorbitol quality produced under these conditions from hydrol H2 had a purity at least equal to that obtained by hydrogenation of a pure dextrose and .is characterised by a very low content of reducing sugars.
TABLE XVI
DP > 3 19.2 21.7 21.0 20.7 .
DP 3 15.9 16.9 16.~ 16.4 . .. __ _ DP 2 51.6 56.1 54.6 54.8 _ Mannitol 3 2 1.8 2 _ __ SORBITOL 10 2.9 5.8 5.7 . .
Reducing sugars 0.3 0.4 0.40 0.4 - _ .
Total sugars 35.0 38.2 36.4 32.2 :
From the results collected in Table XVI, it is deduced that the polyols extracted throughout the balanced 27 ' 13~1503 operation of the chromatography installation had a sorbi-tol content below 10~, which indlcated a very efficient extraction of the sorbi-tol, higher than about 9~7. of the content in sorbitol of the raw material.
As is self-evident and as emerges already besides from the foregoing, the invention is in no way limited to the embodiments and applications which have been more par-ticularly envisaged ; it encompasses, on the contrary, all modifications.
Claims (13)
- C L A I M S
--1. Process for the preparation of improved yields of very high purity sorbitol syrup comprising successively - subjecting a starch hydrolysate to a catalytic hy-drogenation step resulting in a hydrogenated starch hydro-lysate, - subjecting the said hydrogenated starch hydroly-sate to a chromatographic separation step resulting in two fractions, the first of which contains very pure sorbitol and the second of which contains sorbitol, non-hydrogenat-ed sugars and hydrogenated di- and polysaccharides, - subjecting the said second fraction to an acid hydrolysis step capable of hydrolyzing at least 40% by weight of said hydrogenated di- and polysaccharides, to provide a partially hydrogenated starch hydrolysate, and - recirculating the said partially hydrogenated starch hydrolysate to the said catalytic hydrogenation step. - 2. Process according to claim 1, wherein the said starch hydrolysate comprises between 65 and 97% of dex-trose by weight based on dry matter.
- 3. Process according to claim 1, wherein the said starch hydrolysate comprises between 70 and 95% of dex-trose by weight based on dry matter.
- 4. Process according to claim 1, wherein the said starch hydrolysate is constituted by mother liquors or hydrols derived from the crystallization of dextrose in one, two or three crops.
- 5. Process according to claim 1, wherein the said catalytic hydrogenation step is carried out on a Raney nickel catalyst, at a hydrogen pressure comprised between and 70 kg/cm2 and at a temperature from about 100 to 150°C.
- 6. Process according to claim 1, wherein the said chromatographic separation step is carried out disconti-nuously or continuously on a strong acid cationic resin charged with alkaline or alkaline earth ions.
- 7. Process according to claim 1, wherein the chromatographic separation step is carried out disconti-nuously or continuously on zeolite charged with an ion selected from the group consisting of ammonium, sodium, potassium, calcium, strontium or barium ions.
- 8. Process according to claim 1, wherein the chromatographic separation step is carried out with the assistance of several chromatography columns, each of which comprises an inlet and an outlet and is filled with strong cationic resin in the calcium form and of fine gra-nulometry, the said several chromatographic columns being connected serially by pipes connecting the outlet of a given column to the inlet of the following one, each of the said connecting pipes being provided with electro-valves, the said electrovalves being set to form a zone I
of desorption at the head of which water for desorption is introduced, a zone II of adsorption at the head of which the hydrogenated starch hydrolysate is introduced and a zone III of enrichment of the hydrogenated polysacchari-des, the hydrogenated starch hydrolysate and the desorp-tion water forming a liquid phase, a closure device main-taining total fluid-tightness between said zone III, at the end of which are recovered the hydrogenated polysac-charides, and said zone I at the end of which is recovered the sorbitol, said closure device ensuring the direction of the passage of the liquid phase over the said resin and avoiding particularly contamination of the pure sorbitol by traces of polysaccharides. - 9. Process according to claim 1, wherein the said acid hydrolysis step is carried out by passing the said second fraction over a fixed bed containing acid catalysts selected from the group consisting of of alumino-silicate, silica, alumina or cationic resin in the acid form.
- 10. Process according to claim 1, wherein the acid hydrolysis step is carried out by passing the said second fraction over an acid catalytic bed of strong cationic re-sins in the acid form, at a temperature comprised between and 120°C, the passage flow rate over the acid cata-lytic bed being regulated to hydrolyze at least 60% by weight of the hydrogenated di- and polysaccharides.
- 11. Process according to claim 1, wherein the acid hydrolysis step is carried by passing said second fraction over an acid catalytic bed of strong cationic resins in the acid form, at a temperature comprised between 50 and 120°C, the passage flow rate over the acid catalytic bed being regulated to hydrolyze at least 80% of the hydroge-nated di- and polysaccharides.
- 12. Process according to claim 1, wherein the said second fraction subjected to the hydrolysis step has a dry matter content comprised between 1.5% and 30% by weight.
- 13. Process according to claim 1, wherein the said second fraction subjected to the hydrolysis step has a dry matter content comprised between 2.5% and 20% by weight.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8410256A FR2566801B1 (en) | 1984-06-29 | 1984-06-29 | PROCESS FOR THE PREPARATION OF VERY HIGH PURITY SORBITOL SYRUP |
| FR8410256 | 1984-06-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1311503C true CA1311503C (en) | 1992-12-15 |
Family
ID=9305577
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 485530 Expired - Fee Related CA1311503C (en) | 1984-06-29 | 1985-06-27 | Process for the preparation of very high purity sorbitol syrups |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0168315B1 (en) |
| JP (1) | JPS6130543A (en) |
| KR (1) | KR860000311A (en) |
| CN (1) | CN85105753A (en) |
| AT (1) | ATE36696T1 (en) |
| AU (1) | AU606311B2 (en) |
| BR (1) | BR8503133A (en) |
| CA (1) | CA1311503C (en) |
| DE (1) | DE3564563D1 (en) |
| DK (1) | DK296285A (en) |
| FI (1) | FI85851C (en) |
| FR (1) | FR2566801B1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8865948B2 (en) | 2010-10-08 | 2014-10-21 | Roquette Freres | Method for manufacturing high-purity sorbitol syrups from sucrose and uses thereof |
| WO2015107504A1 (en) * | 2014-01-17 | 2015-07-23 | Syral Belgium Nv | Process for preparing a sorbitol rich syrup of high purity |
| WO2016032923A1 (en) * | 2014-08-25 | 2016-03-03 | Archer Daniels Midland Company | Method for the chromatographic separation of sorbitol from dextrose |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3710816A1 (en) * | 1987-03-31 | 1988-10-20 | Focus Control Gmbh Fc | Apparatus for machining a workpiece by means of a laser beam |
| FR2726829B1 (en) * | 1994-11-10 | 1997-01-17 | Roquette Freres | POLYOL COMPOSITION, PROCESS FOR THE PREPARATION THEREOF AND APPLICATIONS THEREOF |
| ATE181723T1 (en) * | 1994-11-10 | 1999-07-15 | Roquette Freres | POLYOL COMPOSITIONS, METHOD FOR THE PRODUCTION THEREOF AND THEIR APPLICATIONS |
| DE10036189A1 (en) * | 2000-07-24 | 2002-02-07 | Dhw Deutsche Hydrierwerke Gmbh | Process for the production of sorbitols from standard glucose |
| US7179336B2 (en) * | 2002-12-30 | 2007-02-20 | Tate & Lyle Europe N.V. | Process for preparing alkali-and heat-stable sugar alcohol compositions and a sorbitol composition |
| FR2876693B1 (en) * | 2004-10-15 | 2007-01-26 | Roquette Freres | PROCESS FOR PREPARING L-IDITOL |
| CN100381412C (en) * | 2006-09-14 | 2008-04-16 | 山东西王糖业有限公司 | Novel technique for preparing ethylene glycol |
| KR101475388B1 (en) * | 2012-12-14 | 2014-12-23 | 주식회사 삼양제넥스 | Method for preparation of anhydrosugar alcohols by using hydrol |
| CN104557463B (en) * | 2014-12-25 | 2016-07-06 | 山东龙力生物科技股份有限公司 | A kind of technique being directly produced high-quality sorbitol for raw material with starch |
| CN108503506A (en) * | 2018-06-25 | 2018-09-07 | 山东兆光色谱分离技术有限公司 | A kind of new process producing high pure sorbitol using chromatographic separation technology |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| NL137813C (en) * | 1963-05-06 | 1900-01-01 | ||
| US4433184A (en) * | 1981-04-27 | 1984-02-21 | Hri, Inc. | Multi-stage catalytic conversion of aldoses to alditols |
| US4442881A (en) * | 1982-08-05 | 1984-04-17 | Don Monteath | Vehicle windshield protective curtain |
-
1984
- 1984-06-29 FR FR8410256A patent/FR2566801B1/en not_active Expired
-
1985
- 1985-06-27 CA CA 485530 patent/CA1311503C/en not_active Expired - Fee Related
- 1985-06-28 FI FI852572A patent/FI85851C/en not_active IP Right Cessation
- 1985-06-28 BR BR8503133A patent/BR8503133A/en unknown
- 1985-06-28 AU AU44412/85A patent/AU606311B2/en not_active Ceased
- 1985-06-28 DE DE8585401324T patent/DE3564563D1/en not_active Expired
- 1985-06-28 DK DK296285A patent/DK296285A/en not_active Application Discontinuation
- 1985-06-28 EP EP19850401324 patent/EP0168315B1/en not_active Expired
- 1985-06-28 AT AT85401324T patent/ATE36696T1/en not_active IP Right Cessation
- 1985-06-29 KR KR1019850004667A patent/KR860000311A/en not_active Application Discontinuation
- 1985-06-29 JP JP14381985A patent/JPS6130543A/en active Pending
- 1985-07-27 CN CN198585105753A patent/CN85105753A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8865948B2 (en) | 2010-10-08 | 2014-10-21 | Roquette Freres | Method for manufacturing high-purity sorbitol syrups from sucrose and uses thereof |
| WO2015107504A1 (en) * | 2014-01-17 | 2015-07-23 | Syral Belgium Nv | Process for preparing a sorbitol rich syrup of high purity |
| BE1022608B1 (en) * | 2014-01-17 | 2016-06-15 | Syral Belgium Nv | PROCESS FOR PREPARING A SORBITOL RICH SYRUP OR HIGH PURITY |
| WO2016032923A1 (en) * | 2014-08-25 | 2016-03-03 | Archer Daniels Midland Company | Method for the chromatographic separation of sorbitol from dextrose |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2566801A1 (en) | 1986-01-03 |
| DK296285A (en) | 1985-12-30 |
| BR8503133A (en) | 1986-03-18 |
| AU606311B2 (en) | 1991-02-07 |
| JPS6130543A (en) | 1986-02-12 |
| FI85851C (en) | 1992-06-10 |
| FI852572L (en) | 1985-12-30 |
| FR2566801B1 (en) | 1986-12-26 |
| AU4441285A (en) | 1986-01-02 |
| FI85851B (en) | 1992-02-28 |
| DK296285D0 (en) | 1985-06-28 |
| DE3564563D1 (en) | 1988-09-29 |
| CN85105753A (en) | 1987-01-28 |
| ATE36696T1 (en) | 1988-09-15 |
| EP0168315B1 (en) | 1988-08-24 |
| KR860000311A (en) | 1986-01-28 |
| FI852572A0 (en) | 1985-06-28 |
| EP0168315A1 (en) | 1986-01-15 |
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