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1.
The reactive extraction of succinic acid was carried out by mixed tertiary amine which consisted of tripropylamine (TPA) and trioctylamine (TOA) as the extraction agent in 1-octanol/n-heptane diluent. Maximum distribution coefficient was obtained at 8:2 weight ratio of TPA/TOA. At this ratio, its extraction efficiency is above 90% at the 3.9 wt.% of succinic acid in aqueous solution. Furthermore, the prevention of the third phase formation made the phase separation between organic phase and aqueous phase easy.  相似文献   

2.
In production of succinic acid by fermentation, succinic acid and acetic acid are co-produced. To purify the succinic acid from binary-acid mixture of succinic acid and acetic acid, the tertiary amine-based extraction was used. In 1-octanol, the selectivity for succinic acid was proportional to the chain length of tertiary amine. But, the distribution of acids into organic phase was low in n-heptane. These results are due to the different degree of intramolecular hydrogen bonding of succinic acid and hydrophobicity of each acid.  相似文献   

3.
A study of the PDSE (predispersed solvent extraction) for succinic acid by colloidal liquid aphrons was conducted. The organic phase contaning TOA (tri-n-octylamine) and 1-octanol permits a selective extraction of succinic acid from its aqueous solution. There was no difference of the extractability of PDSE and that of conventional mixer-settler type extraction. Taking into account the no mechanical mixing in PDSE, it was concluded that the PDSE process is more adaptive than the conventional mixer-settler type extraction process. From mass transfer analysis at the various concentration of TOA in counter-current continuous operation, the concentration of TOA had no influence on the mass transfer coefficient. The loading values in continuous PDSE were almost same as those in batch operation.  相似文献   

4.
We introduce a reactive extraction to detoxify hydrolysate before fermentation to biofuels. In the selection of diluents, n-octanol showed the highest removal yield of 5-hydroxymethylfurfural (5-HMF) and levulinic acid. The removal yields of inhibitors were normalized to 30-min reactions. In treatments with pure extractant or diluents, only 2 ~ 4.1% of the formic acid was removed. Tri-n-octylamine (extractant) removed levulinic acid and acetic acid more efficiently, and furfural was removed more efficiently than formic acid or 5-HMF. n-Octanol (polar diluent) removed levulinic acid and acetic acid, furfural, and 5-HMF at 21.2, 33.7, and 65.7%, respectively. In contrast, kerosene (inert diluent) only removed the furfural by 27.6%. Based on these results, the optimum reactiveextraction system comprised tri-n-octylamine as the extractant, n-octanol as the polar diluent, and kerosene as the inert diluent. The optimal proportion of complex extractant was 20% trialkylamine, 70% n-octanol, and 10% kerosene. By detoxification, 63.9% of acetic acid and levulinic acid, 24.4% of 5-HMF, 63.9% of formic acid, and 64.0% of furfural could be removed.  相似文献   

5.
Removal of tylosin from its dilute aqueous solutions was studied applying the Rotating Film-pertraction technique. Non-toxic and practically water insoluble alcohols as n-octanol and n-decanol were used as intermediate, membrane liquid. A 0.001 mol/l solution of HCl was used as a stripping phase. Effects of temperature, feed phase pH-value and solute concentration on antibiotic distribution coefficients were obtained for both systems. It was found that the first two parameters have important effect, while the solute concentration in the studied range (0.02-0.1 g/l) did not modify these coefficients. Results obtained show that the first pertraction step - solute extraction from the feed - is a very fast process, while the second one - the alcohol stripping - is relatively slow, in particular when octanol was used as membrane phase. A mathematical model was proposed and used for evaluation of corresponding local mass transfer coefficients.  相似文献   

6.
Non-dispersive reactive extraction of cephalosporin antibiotics has been studied using hollow fiber membrane modules. Extraction as well as stripping has been studied using a pH swing procedure. Cephalosporin was extracted from an aqueous solution of cephalosporin having a pH above the pKa2 value to an organic phase containing Aliquat-336 as the extractant and n-heptane as the diluent. The solute was stripped from the loaded organic phase to another aqueous phase of pH maintained well below the pKa2 value of the cephalosporin. The extraction cum stripping relies on pH dependance of the distribution coefficient of cephalosporin in aqueous phase. Reasonably high solute recovery and mass transfer rate have been achieved in the hollow fiber module. Mass transfer performance of a single module has been evaluated and experimentally observed low value of height of transfer unit (HTU) indicates good prospect of hollow fiber membrane for the extraction duty.  相似文献   

7.
Several concentrations ofn-alkanols from methanol to octanol have been added to cultures ofAureobasidium pullulans, and the minimal concentration inducing hyphal development (hyphae inducer concentration) for each one has been determined. An inverse relationship between inducer concentration and hydrocarbon chain length was observed up ton-hexanol (n-heptanol andn-octanol did not allow any growth). The morphogenetic inducer potency, defined as the inverse of the hyphae inducer concentration, was exponentially related to the chain length of the alcohol, as was the membrane/buffer partition coefficient. The morphogenetic inducer potency of the alcohols from methanol ton-hexanol was a function of their membrane solubility, all showing the same intramembrane inducer concentration.  相似文献   

8.
The extraction of seven tricyclic antidepressant amines from human plasma at different pH values was investigated for dichloromethane, diethyl ether and hexane—1-pentanol (95:5). The amines were extracted as bases and back-extracted to sulphuric acid, 0.10 mol/l, prior to the separation by bonded-phase liquid chromatography. Ether and hexane— 1-pentanol (95:5) were most suitable, tertiary amines being best extracted at pH 8, and secondary amines at pH 10. Using ether, both tertiary and secondary amines required 30 min extraction time for a quantitative yield while 15 rain was sufficient for hexane— -1-pentanol (95:5). UV detection allowed concentrations down to 10 ng in 1 ml of plasma to be determined.Three ammonium ions—octylammonium, dimethylammonium, and trimethylammonium - were added as modifiers to the mobile phase containing acetonitrile in phosphoric acid, 0.10 mol/l. In the concentration interval 0.010–0.030 mol/l all of the amine modifiers gave on Polygosil C8 peak asymmetry factors of sufficiently low magnitude, while on Li- Chrosorb RP-18 this was so only for di- and trimethylammonium in a concentration of 0.030 mol/l.  相似文献   

9.
The potential of recovering propionic acid from discharged water in vitamin B12 production by anaerobic fermentation was investigated in this paper. A primary amine, N1923, was used as the extractant, kerosene as diluter and n-octanol as modifier. The influences of the content of N1923 in the organic phase, the phase ratio and the pH of aqueous phase on the extraction yield of propionic acid were studied. The organic phase composition with the volume ratio was proposed of N1923:kerosene:n-octanol as 45:35:20. Under conditions of the phase ratio (o/w) as 1:4, the pH of aqueous phase of 3.0 and after 5 min extraction, the extraction yield of propionic acid can be over 97%.  相似文献   

10.
IN experimental conditions, nitrite can interact with secondary amines in the rodent stomach at mildly acid pH to form nitrosamines1–4, a large number of which are potent carcinogens5. As tertiary amines also react in this way6, we have examined the analgesic aminopyrine, 4-dimethylaminoantipyrine (pyramidon), as being representative of many commonly used tertiary amine drugs.  相似文献   

11.
This paper presents the reactive extraction of propionic acid from aqueous solution by amine based extractants such as tri-n-octylamine and Aliquat 336, dissolved in a mixture of n-dodecane and 1-decanol. Equilibrium experiments were carried out to investigate the effects of various parameters such as modifier (1-decanol) concentration, extractant type, extractant composition, diluent composition, and initial acid concentration on the extraction efficiency. The extraction efficiency was found to be increased with an increase in modifier composition and extractant composition, and decreased with increases in initial acid concentration. Different biocompatible extractant/diluent systems such as (1) 20% TOA, 20% 1-decanol and 60% n-dodecane, (2) 20% TOA, 30% 1-decanol and 50% n-dodecane, (3) 30% TOA, 20% 1-decanol and 50% n-dodecane and (4) 25% Aliquat 336, 25% 1-decanol and 50% n-dodecane are developed and used in this study. A mathematical model based on mass action law and a population-based search algorithm (differential evolution, DE) is proposed, and is used to estimate the extraction equilibrium constant (K E) and stoichiometry of reactive extraction. Individual equilibrium constants for the simultaneous formation of (1:1) and (2:1) acid:amine complexes are also determined. The extraction system comprised of 20% TOA, 30% 1-decanol, and 50% n-dodecane was found to be the best among the four biocompatible extractant/diluent systems studied. The loading ratios found in the range of 0.113 ~ 1.05 indicated the simultaneous formation of 1:1 and 2:1 complexes between acid and TOA.  相似文献   

12.
The peptide synthesis from N-acetyl-L-tyrosine ethyl ester and amino acid amides was realized using α-chymotrypsin as a catalyst in ethanol or acetonitrile containing small amounts of water. In these reaction systems, the precipitates of phosphate salt, which was used as a component of buffer solution, are considered to act as carriers of chymotrypsin. It was found that peptide formation is competitive with hydrolysis of the substrate ester, but the secondary synthesis of the peptide from the hydrolysate was also considered to proceed. The yield of the peptide after 24 h reaction was strongly dependent on the water concentration; maximum yields of the peptide were obtained at water concentrations below 10% (v/v). The addition of tertiary amines, such as triethyl amine, markedly increased the peptide yield, probably due to the increase in the concentration of the nucleophilic amine components by neutralization of hydrohalides of amino acid amides. The effect of reaction temperature and the reactions with CT immobilized on PVA, chitosan, or TEAE-cellulose are also described.  相似文献   

13.
Biotechnologically produced succinic acid has the potential to displace maleic acid and its uses and to become an important feedstock for the chemical industry. In addition to optimized production strains and fermentation processes, an efficient separation of succinic acid from the aqueous fermentation broth is indispensable to compete with the current petrochemical production processes. In this context, high molecular weight amines are known to be effective extractants for organic acids. For this reason, as a first step of isolation and purification, the reactive extraction of succinic acid was studied by mixing aqueous succinic acid solutions with 448 different amine–solvent mixtures as extraction agents (mixer-settler studies). The extraction agents consist either of one amine and one solvent (208 reactive extraction systems) or two amines and two solvents (240 reactive extraction systems). Maximum extraction yields of succinic acid from an aqueous solution with 423 mM succinic acid at pH 2.0 were obtained with more than 95% yield with trihexylamine solved in 1-octanol or with dihexylamine and diisooctylamine solved in 1-octanol and 1-hexanol. Applying these optimized reactive extraction systems with Escherichia coli fermentation broth resulted in extraction yields of 78–85% due to the increased ionic strength of the fermentation supernatant and the co-extraction of other organic acids (e.g., lactic acid and acetic acid), which represent typical fermentation byproducts.  相似文献   

14.
The hyperiid amphipods Themisto libellula and T. abyssorum are important components of Arctic pelagic ecosystems. Both species are carnivorous and prey on mesozooplankton. They represent a substantial food source for marine vertebrates and are a key link between zooplankton secondary production and higher trophic levels. We present data on the total lipid content, lipid class and fatty acid composition of T. libellula and T. abyssorum from northern Fram Strait and the central Arctic Ocean. Both species had moderate to high lipid contents of 14-42% of body dry mass. In T. abyssorum, total lipid content was correlated to body mass, while T. libellula showed sex-related differences in lipid content. Despite their smaller body size, females of T. libellula had higher lipid contents than males. Wax esters represented the major lipid class in both species with 41-43% of total lipid, while triacylglycerols contributed 23-32%. The fatty acid composition was dominated by the long-chain polyunsaturated moieties 20:5(n-3) and 22:6(n-3), short-chain saturated compounds (16:0 and 14:0) and monounsaturated fatty acids of varying length, i.e. 16:1(n-7), 20:1(n-9), 18:1(n-9) and 22:1(n-11). Species-specific and geographic variations in the fatty acid and alcohol patterns were apparently linked to differences in diet and life-cycle. High amounts of the fatty acids and alcohols 20:1(n-9) and 22:1(n-11) in T. libellula indicate predation on herbivorous Calanus copepodids. In addition, elevated levels of 20:5(n-3) in T. libellula indicate a close connection with ice-algal production and the importance of cryo-pelagic coupling processes (i.e. exchange processes between the sea ice and the pelagic communities) for the nutrition of this high-Arctic epipelagic species. In contrast, T. abyssorum is characterised by lower amounts of 20:5(n-3) and its biomarker ratios indicate a higher trophic level. This observation is consistent with the subarctic-boreal origin of T. abyssorum and its occurrence in deeper layers of the Arctic Ocean, where it may feed on omnivorous and/or carnivorous prey.  相似文献   

15.
The branched structure of potato amylopectin (degree of polymerization ~200,000) was modeled in a computer matrix. The chain-length distribution and the length and width of a cluster of the amylopectin molecule were used as input variables in the model. Independent literature values related to the structure of amylopectin (percentage #-hydrolysis and ratio of A- to B-chains) were used for evaluation of the branching characteristics (length of branch area and chance of branching) of the modeled amylopectin. The structural parameters predicted by the model agreed very well with data from the literature. The chain-length distribution and values for the percentage of #-hydrolysis were the two most important parameters required to model the structure of amylopectin. This computer-generated model of potato amylopectin in solution can be used to simulate various enzymatic (i.e., !-amylase, #-amylase, glucoamylase, pullunanase) or chemical reactions (i.e., acid hydrolysis, hypochlorite oxidation). The modeling approach described in this paper is also suitable for starches from other botanical sources (i.e., corn, wheat, tapioca).  相似文献   

16.
17.
4-Chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) is widely applied as a fluorescent tagging reagent in biochemistry, as a derivatization agent in analytical chemistry, and as a component for design of fluorescent nanoparticles. Four new 7-nitrobenzo-2-oxa-1,3-diazole (NBD)-tagged polyamines containing two to four amine moieties were synthesized and used as an effective tool for staining of siliceous frustules of the diatom algae and spicules of the siliceous sponges, including fossilized samples. An unexpected reaction between NBD-Cl and tertiary amine groups was found, giving rise to NBD-tagged amines with elimination of an alkyl group. The reaction proceeds through the Meisenheimer complex and quaternary salt, which transform to the product by Hofmann reaction (alkene elimination) or nucleophilic substitution (halogenated compound formation). In the case of polyamines, NBD-Cl causes chain scissoring, giving a set of NBD-tagged amines. The found NBD-Cl reaction with tertiary amines must be taken into account when using NBD-Cl and similar activated aromatic systems for amine derivatization in analytical and biochemistry applications. The reaction with polyamines opens the way to libraries of NBD-tagged compounds.  相似文献   

18.
Efficiency and stereoselectivity of condensations of ribonucleoside 3′-H-phosphonates with ethanol promoted by pivaloyl chloride were investigated as a function of tertiary amines used. Side reactions leading to an increased demand for the condensing agent were identified as derived from an attack of the pivalate anion at carbonyl centers of reactive pivaloyl derivatives. The conditions that secured quantitative yields of H-phosphonate diester condensations were assessed. Several tertiary amines promoted condensations with stereoselectivity higher than that observed for pyridine derivatives. A correlation between diastereoselectivity of the product formation and Brønsted and H-bonding basicities of the amine used was found.  相似文献   

19.
The separation of lactic acid from complex fermentation broth was examined. Liquid–liquid extraction using reversible chemical complexation for reactive extraction was chosen to be the separation method. Over 50% yield of lactic acid was obtained from fermented broth in a single extraction step, when using the tertiary amine as the extractant, 1-dekanol as the diluent and trimethylamine (TMA) as the stripping solution. The effect of complex media on the extraction behaviour has hardly been examined previously.  相似文献   

20.
Extracellular lipase from Bacillus coagulans BTS-3 was immobilized on (3 Å × 1.5 mm) molecular sieve. The molecular sieve showed approximately 68.48% binding efficiency for lipase (specific activity 55 IU mg?1). The immobilized enzyme achieved approx 90% conversion of acetic acid and 4-nitrophenol (100 mM each) into 4-nitrophenyl acetate in n-heptane at 65°C in 3 h. When alkane of C-chain length other than n-heptane was used as the organic solvent, the conversion of 4-nitrophenol and acetic acid was found to decrease. About 88.6% conversion of the reactants into ester was achieved when reactants were used at molar ratio of 1:1. The immobilized lipase brought about conversion of approximately 58% for esterification of 4-nitrophenol and acetic acid into 4-nitrophenyl acetate at a temperature of 65°C after reuse for 5 cycles.  相似文献   

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