Long Chaina-phosphono fatty acids,salts and esters

A series of α-phosphono fatty acids and their salts and esters was prepared from pelargonic, capric, lauric, myristic, palmitic, and stearic acids. In comparison to correspondingα-sulfo fatty acids theα-phosphono fatty acids are white solids of higher melting point, weaker acids, less hygroscopic, have a lower critical micelle concentration and are less resistant to hard water. Methyl, isopropyl, and amyl esters RCH. [PO (OH)₂] CO₂R′, were prepared from the α-phosphono fatty acids ; a sulfuric acid catalyst was required in the case of lower boiling alcohols. Hydrolysis studies with sodium methylα-phosphonomyristate showed the a-phosphono ester to be 50 times as stable towards alkali as the correspondingα-sulfo ester, but only one-tenth as stable toward acid hydrolysis. Wetting, foaming, detergent, and other surface active properties of theα-phosphono fatty acids, salts, and esters were measured and compared with those of analogousα-sulfo compounds.     

Volatiles Emitted by Calling Males of Burying Beetles and <Emphasis Type="Italic">Ptomascopus morio</Emphasis> (Coleoptera: Silphidae: Nicrophorinae) Are Biogenetically Related

In burying beetles, Nicrophorus spp. (Coleoptera: Silphidae: Nicrophorinae) mate finding is mediated by male produced volatile compounds. To date, pheromone components of only two species have been identified. In an attempt to better understand the evolution of male pheromone signaling in burying beetles, we investigated the male released volatiles of ten Nicrophorus species and one closely related nicrophorine species, Ptomascopus mori. Volatiles emitted by calling males were collected in the laboratory by means of solid phase micro extraction and analyzed using gas chromatography coupled with mass spectrometry. Identified volatiles included short chain esters of 4-methylcarboxylic acids, terpenoids, and some other aliphatic compounds. The long-range volatile signals of the burying beetle species included in this study are blends of two to seven components. We found that methyl or ethyl esters of 4-methylheptanoic acid and 4-methyloctanoic acid are produced by eight of the ten investigated Nicrophorus species. These esters may play a key role in chemical communication. Their widespread occurrence suggests that these compounds did not evolve recently, but appeared relatively early in the phylogeny of the genus. Although Ptomascopus is considered the sister genus of Nicrophorus, P. morio males do not produce any of the Nicrophorus compounds, but release 3-methylalkan-2-ones, which are absent in Nicrophorus. A better understanding of the evolution of burying beetle pheromones, however, will only be possible once more species have been studied.     

Lipids of the Tail Gland,Body and Muzzle Fur of the Red Fox, <Emphasis Type="Italic">Vulpes vulpes</Emphasis>

The tail gland of the red fox (Vulpes vulpes) secretes lipids containing volatile terpenes used in social communication. We have analysed lipids extracted from fur of the tail gland, body (flanks) and muzzle of foxes. GC–MS showed a novel group of iso-valerate and tiglate monoesters of alkane-1,2-diols (C18:0–22:0). There was also a larger group of Type II diesters in which a second, longer chain, fatty acid (FA) was attached to the free alcohol group. LC–MS showed the full range of diol diesters, mostly C36:0–50:0, with smaller amounts of the corresponding mono-unsaturated tiglate esters. An additional group of diesters with higher MW (C49:0–62:0) containing two long-chain FA was present in the lipids of body and muzzle fur. After saponification and GC–MS, 98 fatty acids were characterized as their methyl esters. Apart from the C5 FA, most were saturated n-, iso-, anteiso- or other methyl-branched FA (C12:0–28:0) whose structures were determined by a combination of their mass spectra and Kovats retention indices. Several FA have not previously been found in nature or in vertebrates. Thirty-four alkane-1,2-diols were found as their TMS derivatives, mostly n-, iso- or anteiso-isomers of C16:0–25:0. The tail gland had the greatest amount of wax esters, from a greater variety of FA and diols, but lacked the esters with two long-chain FA. These findings show that fox skin lipids comprise mono- and di-esters of alkane-1,2-diols, and exhibit enormous complexity due to the diversity of their constituent FA, diols and the many possible isomers of their esters.     

Comparison of the Chemical Compositions of the Cuticle and Dufour’s Gland of Two Solitary Bee Species from Laboratory and Field Conditions

Species-specific biochemistry, morphology, and function of the Dufour’s gland have been investigated for social bees and some non-social bee families. Most of the solitary bees previously examined are ground-nesting bees that use Dufour’s gland secretions to line brood chambers. This study examines the chemistry of the cuticle and Dufour’s gland of cavity-nesting Megachile rotundata and Osmia lignaria, which are species managed for crop pollination. Glandular and cuticular lipid compositions were characterized and compared to each other and according to the nesting experience of adult females. Major lipid classes found were hydrocarbons, free fatty acids, and wax esters. Many components were common to the cuticle and Dufour’s glands of each species, yet not identical in number or relative composition. Wax esters and fatty acids were more prevalent in Dufour’s glands of M. rotundata than on cuticles. Wax esters were more abundant on cuticles of O. lignaria than in Dufour’s glands. In both species, fatty acids were more prevalent in glands of field-collected females compared to any other sample type. Chemical profiles of cuticles and glands were distinct from each other, and, for O. lignaria, profiles of laboratory-maintained bees could be distinguished from those of field-collected bees. Comparison of percentiles of individual components of cuticular and glandular profiles of the same bee showed that the proportions of some cuticular components were predictive of the proportion of the same glandular components, especially for nesting females. Lastly, evidence suggested that Dufour’s gland is the major source of nest-marking substances in M. rotundata, but evidence for this role in O. lignaria was less conclusive.     

Isolation of Non-methylene Interrupted or Acetylenic Fatty Acids from Seed Oils Using Semi-preparative Supercritical Chromatography

Preparative scale supercritical fluid chromatography was used for isolating and purifying uncommon non-methylene interrupted or acetylenic polyunsaturated fatty acids ethyl esters from seed oils. Fractionation of Biota orientalis seed oil ethyl esters was performed by supercritical fluid chromatography to obtain juniperonic acid [(5Z,11Z,14Z,17Z)-eicosa-5,11,14,17-tetraenoic acid], a non-methylene interrupted polyunsaturated fatty acid. Fractionation of sandalwood seed oil ethyl esters yielded ximenynic acid [(E)-octadec-11-en-9-ynoic acid], an acetylenic polyunsaturated fatty acid. The effects of CO₂ flow rate, column stationary phase and particle size were explored to optimize ximenynic and juniperonic ethyl ester recovery and purity from ethyl ester mixtures using online UV/Vis detection. Particle size, followed by the stationary phase, were found to be the most important parameters to achieving good separation. Under optimized conditions, ximenynic and juniperonic ethyl ester purities greater than 99 and 95%, respectively, were achieved in a one step process without co-solvent. The isolation and recovery of juniperonic acid from biota seed oil free fatty acids was also attempted. Using free fatty acids as the feed material, the non-methylene interrupted polyunsaturated sciadonic acid was also able to be separated from other compounds including juniperonic acid under some conditions, and gave an increase in concentration of more than 17 times.     

Identification of Crepenynic Acid in the Seed Oil of <Emphasis Type="Italic">Atractylodes lancea</Emphasis> and <Emphasis Type="Italic">A. macrocephala</Emphasis>

Atractylodes rhizome is widely used in traditional Chinese herbal medicine. Although the chemical composition of the root has been studied in detail, the oil content and fatty acid composition of the seeds of Atractylodes species have not been reported. Fatty acyl composition of seeds from Atractylodes lancea and A. macrocephala was determined by gas chromatography and mass spectrometry of fatty acid methyl esters and 3-pyridylcarbinol esters. The predominant fatty acid in the seeds of both species was linolenic acid, but the unusual acetylenic fatty acid, crepenynic acid (cis-9-octadecen-12-ynoic acid), was also observed at levels of 18% in A. lancea and 13–15% in A. macrocephala. Fatty acid content was 24% for the samples of A. lancea and 16–17% for samples from A. macrocephala. sn-1,3 regioselective lipase digestion of seed lipids revealed that crepenynic acid was absent from the sn-2 position of the seed triacylglycerol. Crepenynic acid was also found in the seed oil of Jurinea mollis at 24% and was not present in the sn-2 position of the TAG. A contrasting distribution of crepenynic acid was found in the oil of Crepis rubra, suggesting differences in crepenynic acid synthesis or TAG assembly between these species.     

Stingless Bees: Chemical Differences and Potential Functions in <Emphasis Type="Italic">Nannotrigona testaceicornis</Emphasis> and <Emphasis Type="Italic">Plebeia droryana</Emphasis> Males and Workers

Cuticular wax, abdominal and cephalic extracts of foraging workers and males of Nannotrigona testaceicornis and Plebeia droryana, from the “Aretuzina” farm in São Simão, SP, Brazil, were analyzed by GC-MS. The principal constituents were hydrocarbons, terpenes, aldehydes, esters, steroids, alcohols, and fatty acids. Interspecific differences for both cuticular wax and cephalic extracts were found. The composition of cuticular wax and cephalic extracts was similar at the intraspecific level, with minor component differences between males and workers. Abdominal extracts differentiated sexes (male and worker) at the intraspecific and interspecific levels. The main chemical components in abdominal extracts of N. testaceicornis workers and males were geranylgeranyl acetate and (Z)-9-nonacosene, respectively. The principal components of abdominal extracts from P. droryana workers and males were tetradecanal and unsaturated fatty acids (linoleic and linolenic acids), respectively. A secondary alcohol, (S)-2-nonanol, was detected in Plebeia droryana males only, but not in workers. Preliminary field experiments showed that (S)-(+)-2-heptanol and (S)-(+)-2-heptanol/ (S)-(+)-2-nonanol (1:1) attracted workers of P. droryana, N. testaceicornis, and Frieseomelitta silvestrii. However, males did not respond suggesting that these compounds do not function as alarm or recruitment pheromones . In addition, racemic mixtures were inactive.     

Microbial Conversion of Arachidonic Acid to Arachidonyl Alcohol by a New <Emphasis Type="Italic">Acinetobacter</Emphasis> Species

Arachidonyl alcohol rarely occurs in natural oils. It can be used as a substrate for production of several ether lipids possessing beneficial functions. Although arachidonyl alcohol has been produced on a laboratory scale by the chemical reduction of arachidonic acid, it will be difficult to scale up this process for industrial application. The aim of this study was to develop a new bioprocess for converting arachidonic acid to arachidonyl alcohol. Screening was conducted using 11 wax ester- (esters of fatty acids and fatty alcohols) producing strains reported in our previous study, and a single-cell oil containing arachidonic acid. A new strain, Acinetobacter species N-476-2, most effectively converted arachidonic acid to arachidonyl alcohol, which accumulated inside the cells as a wax ester. GC–MS, FT–IR, and NMR analyses showed that this strain reduced the carboxyl group of 5-cis,8-cis,11-cis,14-cis-arachidonic acid to a hydroxyl group without altering the position or configuration of the double bonds; the product was identified as 5-cis,8-cis,11-cis,14-cis-arachidonyl alcohol. A time-course study of cultivation showed that the amount of arachidonyl alcohol produced by the strain after 4 days was 2.2 mg/mL culture. The bioprocess using Acinetobacter sp. N-476-2 can be applied to the large-scale production of arachidonyl alcohol.     

Tarsi of Male Heliothine Moths Contain Aldehydes and Butyrate Esters as Potential Pheromone Components

The Noctuidae are one of the most speciose moth families and include the genera Helicoverpa and Heliothis. Females use (Z)-11-hexadecenal as the major component of their sex pheromones except for Helicoverpa assulta and Helicoverpa gelotopoeon, both of which utilize (Z)-9-hexadecenal. The minor compounds found in heliothine sex pheromone glands vary with species, but hexadecanal has been found in the pheromone gland of almost all heliothine females so far investigated. In this study, we found a large amount (0.5–1.5 μg) of hexadecanal and octadecanal on the legs of males of four heliothine species, Helicoverpa zea, Helicoverpa armigera, H. assulta, and Heliothis virescens. The hexadecanal was found on and released from the tarsi, and was in much lower levels or not detected on the remaining parts of the leg (tibia, femur, trochanter, and coxa). Lower amounts (0.05–0.5 μg) of hexadecanal were found on female tarsi. This is the first known sex pheromone compound to be identified from the legs of nocturnal moths. Large amounts of butyrate esters (about 16 μg) also were found on tarsi of males with lower amounts on female tarsi. Males deposited the butyrate esters while walking on a glass surface. Decapitation did not reduce the levels of hexadecanal on the tarsi of H. zea males, indicating that hexadecanal production is not under the same neuroendocrine regulation system as the production of female sex pheromone. Based on electroantennogram studies, female antennae had a relatively high response to hexadecanal compared to male antennae. We consider the possible role of aldehydes and butyrate esters as courtship signals in heliothine moths.     

Synthesis and physical properties of Curdlan branched Ester derivatives

Curdlan is a high-molecular-weight linear β-1,3-glucan synthesized by microorganisms. A series of curdlan branched esters with a degree of substitution of three were synthesized and their physical properties and structures were compared with those of curdlan linear esters. Thermal degradation temperatures of all the curdlan branched esters were ca. 360 °C; almost the same as those of curdlan linear esters. The curdlan branched esters had melting temperatures (T _m ) higher than those of the corresponding curdlan linear ester with the same side-chain carbon number. In particular, comparing T _m of curdlan propionate, curdlan isobutyrate, and curdlan pivalate, the latter two had high T _m of over 335 °C, suggesting that the degree of branching of the side chain affects the stability of molecular chains with helix structure in their crystals. Highly transparent films were prepared from the curdlan branched esters. These films exhibited higher Young’s modulus and tensile strength compared with those of films composed of the linear equivalents with the same side-chain carbon numbers. These results indicate that curdlan branched esters are promising thermoplastics with favorable thermal and mechanical properties because of the closer packing structure of their molecular chains than that of the corresponding curdlan linear esters.     

(1<Emphasis Type="Italic">S</Emphasis>,3<Emphasis Type="Italic">R</Emphasis>)-<Emphasis Type="Italic">cis</Emphasis>-Chrysanthemyl Tiglate: Sex Pheromone of the Striped Mealybug, <Emphasis Type="Italic">Ferrisia virgata</Emphasis>

Derivatives of 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid (chrysanthemic acid) are classic natural pyrethroids discovered in pyrethrum plants and show insecticidal activity. Chrysanthemic acid, with two asymmetric carbons, has four possible stereoisomers, and most natural pyrethroids have the (1R,3R)-trans configuration. Interestingly, chrysanthemic acid–related structures are also found in insect sex pheromones; carboxylic esters of (1R,3R)-trans-(2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl)methanol (chrysanthemyl alcohol) have been reported from two mealybug species. In the present study, another ester of chrysanthemyl alcohol was discovered from the striped mealybug, Ferrisia virgata (Cockerell), as its pheromone. By means of gas chromatography–mass spectrometry, nuclear magnetic resonance spectrometry, and high-performance liquid chromatography analyses using a chiral stationary phase column and authentic standards, the pheromone was identified as (1S,3R)-(?)-cis-chrysanthemyl tiglate. The (1S,3R)-enantiomer strongly attracted adult males in a greenhouse trapping bioassay, whereas the other enantiomers showed only weak activity. The cis configuration of the chrysanthemic acid–related structure appears to be relatively scarce in nature, and this is the first example reported from arthropods.     

Acid-catalyzed regeneration of fatty-acid-adsorbed <Emphasis Type="Italic">γ</Emphasis>-alumina via transesterification with methanol

Fatty-acid-adsorbed γ-alumina was regenerated via transesterification using methanol with sulfuric acid as a catalyst. The fatty acids adsorbed on γ-alumina were converted to fatty acid methyl esters (FAME) and desorbed from the γ-alumina during the acid-catalyzed methanol regeneration process. A series of experiments studied the effect of the operating parameters (temperature, amount of sulfuric acid (wt%), methanol-solution-to-γ-alumina weight ratio, and regeneration time) on the acid-catalyzed methanol regeneration process. The chemically adsorbed fatty acids were desorbed effectively above 100 °C when the amount of sulfuric acid was 3 wt%, the methanol-solution-to-γ-alumina weight ratio was higher than 5: 1, and the regeneration time was longer than 30 min. This new approach provides an ecofriendly process that operates at much lower temperatures than other methods of regeneration (thermal and supercritical methanol) while producing a renewable fuel.     

Composition of the lipids of the sphagnum and cotton grass peats in the forest steppe and southern and middle taigas of West Siberia

The composition of the organic components of the lipids of sphagnum and cotton grass peats deposited in West Siberia in the limits of different natural climatic zones was studied by chromatography–mass spectrometry. A decrease in the temperature and an increase in the humidity of the environment northwards from the forest steppe to the middle taiga was accompanied by an increase in the concentration of steroids, tocopherols, and pentacyclic triterpenoids in sphagnum peats and by a decrease in the fraction of n-alkanes, n-alkan-2-ones, and carboxylic acids. The relative concentration of carboxylic acids and their methyl esters and also the fraction of n-aldehydes and steroids, in particular, sitosterol, in cotton grass peats were maximal in the zone of a reduced temperature and an excess humidity of air; the relative alkanone content was simultaneously lowered. In general, the peats of the forest-steppe zone were characterized by the decreased concentrations of all of the identified components of lipids other than n-aldehydes and n-alkan-2-ones; the peats of the southern taiga zone were enriched in branched acyclic structures, carboxylic acids and their esters, tocopherols, and cyclic sesqui- and diterpenoids, whereas the peats of the middle taiga zone were enriched in steroids and pentacyclic triterpenoids.     

Identification of the Unsaturated Heptadecyl Fatty Acids in the Seed Oils of <Emphasis Type="Italic">Thespesia populnea</Emphasis> and <Emphasis Type="Italic">Gossypium hirsutum</Emphasis>

The fatty acid composition of the seed oils of Thespesia populnea and cotton variety SG-747 (Gossypium hirsutum) were studied to identity their 17-carbon fatty acids. With a combination of chemical derivatization, gas chromatography, and mass spectrometry, 8-heptadecenoic acid, 9-heptadecenoic acid, and 8,11-heptadecadienoic acids were identified in both oils. Additionally, traces of 10-heptadecenoic acid were identified in the T. populnea oil. Although these odd-carbon number fatty acids are present in only minor amounts in cottonseed oil, they make up about ~2 % of the fatty acids in T. populnea seed oil. The identification of these acids indicates that fatty acid α-oxidation is not restricted to cyclopropene fatty acids in these plants, but also occurs with unsaturated fatty acids. Combined with malvalic acid (generally accepted as being formed by α-oxidation of sterculic acid), ~7 % of the fatty acids in T. populnea seed have under gone α-oxidization. The results should help clarify the composition of T. populnea seed oil, which has been reported inconsistently in the literature.     

Selective Enrichment of Conjugated Linoleic Acid Isomers in Their Mixtures Using Combined Chemical and Enzymatic Methods

The aim of this study was to selectively enrich t10,c12-conjugated linoleic acid (t10,c12-CLA) and c9,t11-CLA in commercial CLA mixtures using a combination of urea crystallization and lipase-catalyzed esterification. The objective of the urea fractionation is to remove saturated and monounsaturated fatty acids (FA) from the CLA mixtures. CLA-enriched free FA (FFA) mixtures containing 53.8 wt% t10,c12-CLA and 39.1 wt% c9,t11-CLA were produced from the CLA mixtures containing ~34 wt% each of the two CLA isomers by a urea crystallization using methanol and the urea-to-FA weight ratio of 2.5:1. The CLA-enriched FFA mixtures were partially esterified with dodecan-1-ol in a recirculating packed-bed reactor using an immobilized lipase from Candida rugosa to further enrich the t10,c12-CLA and c9,t11-CLA in an FFA fraction and an FA dodecyl ester fraction, respectively, under the optimal conditions, i.e., temperature, 20 °C; FA-to-dodecan-1-ol molar ratio, 1:1; water content, 2 wt% of total substrates; residence time, 5 min; and reaction time, 24 h (for t10,c12-CLA enrichment) and 12 h (for c9,t11-CLA enrichment). After the reaction, an FFA fraction with 72.6 wt% t10,c12-CLA was obtained. Another FFA fraction with 62.0 wt% c9,t11-CLA was recovered after the saponification of the FA dodecyl ester fraction. The yields of t10,c12-CLA and c9,t11-CLA in the FFA fractions were 43.6 and 21.5 wt%, respectively, based on their initial weights in the CLA mixtures.     

Enzymatic synthesis of butyrates of fusel oil

Many esters derived from lower aliphatic acids and alcohols have pleasant fruity aromas. These compounds are common in the plant kingdom. Some are chemically synthesized and used as fragrances. In this work, fruity flavored butyric esters are produced using lipase agents. The substrate is an alcohol-containing fraction obtained by distilling fusel oil, a waste product of the alcohol industry (T _b = 120–140°С). The yield of the target products in the presence of pancreatic lipase and the lipase from the Candida rugosa yeast is ~94.0% under the determined optimum conditions.     

Pyrolysis kinetics and product properties of softwoods,hardwoods, and the nut shell of softwood

The pyrolysis of softwoods (Pinus (P.) densiflora, P. koraiensis), hardwoods (Quercus acutissima and Liriodendron tulipifera) and nut shell of P. koraiensis was investigated using a thermogravimetric analyzer and fixed bed reactor. Thermogravimetric analysis showed that the maximum decomposition temperature of each biomass was influenced by the ash content and lignocellulosic composition of biomass. The activation energy values also varied according to the content of hemicellulose and lignin of each biomass. Large amounts of acids, such as acetic acid, were recovered from the hardwood pyrolysis reaction due to their high hemicellulose content. The nut shell of P. koraiensis and softwoods with a higher lignin content produced higher yields of phenolic compounds than the hardwoods.     

Smells Like Home: Chemically Mediated Co-Habitation of Two Termite Species in a Single Nest

Termite nests often are referred to as the most elaborate constructions of animals. However, some termite species do not build a nest at all and instead found colonies inside the nests of other termites. Since these so-called inquilines do not need to be in direct contact with the host population, the two colonies usually live in separate parts of the nest. Adaptations of both the inquiline and its host are likely to occur to maintain the spatial exclusion and reduce the costs of potential conflicts. Among them, mutual avoidance, based on chemical cues, is expected. We investigated chemical aspects of cohabitation between Constrictotermes cavifrons (Nasutitermitinae) and its obligatory inquiline Inquilinitermes inquilinus (Termitinae). Inquiline soldiers produce in their frontal glands a blend of wax esters, consisting of the C₁₂ alcohols (3Z)-dodec enol, (3Z,6Z)-dodecadienol, and dodecanol, esterified with different fatty acids. The C₁₂ alcohols appear to be cleaved gradually from the wax esters, and they occur in the frontal gland, in soldier headspace, and in the walls of the inquiline part of the nest. Electrophysiological experiments revealed that (3Z)-dodecenol and (3Z,6Z)-dodecadienol are perceived by workers of both species. Bioassays indicated that inquiline soldier heads, as well as the two synthetic compounds, are attractive to conspecific workers and elicit an arresting behavior, while host soldiers and workers avoid these chemicals at biologically relevant amounts. These observations support the hypothesis that chemically mediated spatial separation of the host and the inquiline is an element of a conflict-avoidance strategy in these species.     

Menzation of mono ethenoid acids during hydrogenation

Methyl petroselinate, methyl oleate, and methyl erucate were hydrogenated under conditions used in industry for selective hydrogenation. The resulting products were separated into saturated esters andtrans- and cis-unsaturated esters on a silver nitrate impregnated silicic acid column. The positional isomers in the total hydrogenated samples and the cis andtrans-fractions were determined by oxidation with permanganate-per-iodate and GLC analysis of the resulting di-carboxylic fragments. Positional isomers were found in bothtrans andcis-fractions with equal shifting of the bond toward and away from the carboxyl group, regardless of whether the bond was originally in the 6,9, or 13 position. The ratio oftrans tocis-form in the positional isomers in all cases was higher than the reported equilibrium proportions of 2:1.     

Enzyme-Catalyzed Synthesis of Monoacylglycerols Citrate: Kinetics and Thermodynamics

The kinetics and thermodynamics of the esterification of citric acid (CA) and monoglycerides (MGs) for citrate esters of monoacylglycerols catalyzed by Novozym 435 in tert-butyl alcohol system was studied in this work. The relationship between initial reaction rate and temperature was established, based on the Arrhenius law. A linear relationship was established between the initial reaction rate and enzyme load up to 3 g/L, which demonstrated that the influence of external mass transfer limitations on the reaction could be eliminated. The reaction kinetics agreed with the Ping-Pong Bi–Bi mechanism with CA inhibition characterized by V _max, K _B, K _A, and K _iA , values of 0.7092 mmol/(min g), 0.0553, 0.0136 and 0.1948 mol/L, respectively. The model was used to simulate the reaction process. The values calculated from the kinetic mode agreed well with the experimental rate data under the different MG and CA concentrations.