Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production.They negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyc...Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production.They negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae strains.Development of industrial S.cerevisiae strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol production.In this study,the acetic acid or furfural tolerance of different S.cerevisiae strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress conditions.The acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^(-1)ethanol with a yield of 0.46 g·g^(-1)in the presence of 9 g·L^(-1)acetic acid,while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^(-1)with increased yield up to 0.49 g·g^(-1)in the presence of both 9 g·L^(-1)acetic acid and 4 g·L^(-1)furfural.Significant improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94,which achieved ethanol production and yield of 29.1 g·L^(-1)and 0.49 g·g^(-1),respectively,the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95%higher than those of wildtype strains,indicating the acetic acid-and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol production.The adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.展开更多
Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as...Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as two comparative catalysts,Ni/Al_(2)O_(3) and Ni/SiO_(2),with low nickel loading(2%(mass))was conducted to probe involvement of the varied carriers in the steam reforming.The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO_(2) and Ni/Al_(2)O_(3),as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C,resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance.In converse,strong adsorption of aliphatic intermediates over Ni/Al_(2)O_(3) and Ni/SiO_(2) induced serious coking with polymeric coke as the main type(21.5%and 32.1%,respectively),which was significantly higher than that over Ni/biochar(3.9%).The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity.The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam,which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al_(2)O_(3) and Ni/SiO_(2) catalysts.展开更多
Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution...Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution(4%v/v)in rats.Rats were divided into six groups including the sham group,the negative control group,the dexamethasone-treated group,and the groups treated with isoimperatorin(0.1,1,and 10 mg/kg/d by gavage).The treatments were administered for three days and then colonic status was assessed by macroscopic,histopathological,and biochemical analyses.Results:Isoimperatorin significantly alleviated colonic damage in a dose-dependent manner and improved histological changes in rats with acetic acid-induced colitis.It also significantly reduced myeloperoxidase,TNF-α,IL-1β,and malodialdehyde levels.Conclusions:Isoimperatorin alleviates acetic acid-induced colitis in rats and may be a potential therapeutic agent for the treatment of colitis.展开更多
Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environ...Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.展开更多
BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against...BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.展开更多
BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capil...BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capillary network,and gastric pits.AIM To evaluate the effectiveness of a new one-dual(near)focus,NBI mode in the assessment of the microscopic features of gastric body mucosa compared to conventional magnification.METHODS During 2021 and 2022,68 patients underwent proximal gastrointestinal endoscopy using magnification endoscopic modalities subsequently applying acetic acid(AA).The GIF-190HQ series NBI system with dual focus capability was used for the investigation of gastric mucosa.At the time of the endoscopy,the gastric body mucosa of all enrolled patients was photographed using the white light endoscopy(WLE),near focus(NF),NF-NBI,AA-NF,and AA-NF-NBI modes.RESULTS The WLE,NF and NF-NBI endoscopic modes for all patients(204 images)were classified in the same order into three groups.Two images from each patient for the AA-NF and AA-NF-NBI endoscopic modes were classified in the same order.According to all three observers who completed the work independently,NF magnification was significantly superior to WLE(P<0.01),and the NF-NBI mode was significantly superior to NF magnification(P<0.01).After applying AA,the three observers confirmed that AA-NF-NBI was significantly superior to AA-NF(P<0.01).Interobserver kappa values for WLE were 0.609,0.704,and 0.598,respectively and were 0.600,0.721,and 0.637,respectively,for NF magnification.For the NF-NBI mode,the values were 0.378,0.471,and 0.553,respectively.For AA-NF,they were 0.453,0.603,and 0.480,respectively,and for AA-NF-NBI,they were 0.643,0.506,and 0.354,respectively.CONCLUSION When investigating gastric mucosa in microscopic detail,NF-NBI was the most powerful endoscopic mode for assessing regular arrangement of collecting venules,subepithelial capillary network,and gastric pits among the five endoscopic modalities investigated in this study.AA-NF-NBI was the most powerful endoscopic mode for analyzing crypt opening and intervening part.展开更多
It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and co...It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and countermeasures were needed. Therefore, we studied the copper corrosion caused by acetic acid. The present work investigated the relationship between the corrosion form of copper and acetic acid concentration using phosphorous-deoxidized copper, and reported that hemispherical corrosion was observed at acetic acid concentrations of 0.01 to 1 vol.% (0.002 to 0.2 mol·L<sup>-1</sup>) in the immersion test. In this study, the effects of acetic acid and phosphate on copper corrosion were examined using oxygen-free copper in immersion tests. The results suggested that different concentrations of phosphate in acetic acid solutions and the presence or absence of acetic acid and phosphate affected the corrosion of copper, resulting in different corrosion forms and corrosion progress.展开更多
BACKGROUND Atractylodes japonica Koidz.ex Kitam.(A.japonica,Chinese name:Guan-Cangzhu,Japanese name:Byaku-jutsu),a perennial herb,which is mainly distributed in northeast area of China,it’s often used to treat digest...BACKGROUND Atractylodes japonica Koidz.ex Kitam.(A.japonica,Chinese name:Guan-Cangzhu,Japanese name:Byaku-jutsu),a perennial herb,which is mainly distributed in northeast area of China,it’s often used to treat digestive system diseases such as gastric ulcer(GU).However,the mechanism of its potential protective effects against GU remains unclear.AIM To investigate the protective effects of A.japonica on acetic acid-induced GU rats.METHODS The chemical constituents of A.japonica were determined by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)analysis.The rat model of GU was simulated by acetic acid method.The pathological changes of gastric tissues were evaluated by hematoxylin-eosin stain,the levels of epidermal growth factor(EGF),EGF receptor(EGFR),nuclear factor kappa-B(NF-κB),interleukin-1β(IL-1β),IL-10,Na^(+)-K^(+)-ATPase(NKA)in serum and gastric tissues were determined by enzyme-linked immunosorbent assay,and the mRNA expressions of EGFR,NF-κBp65,IkappaBalpha(IκBα)and Zonula Occludens-1(ZO-1)in gastric tissues were determined by real-time reverse transcription polymerase chain reaction,and the efficacy was observed.Then,plasma metabolomic analysis was performed by UPLC-MS/MS to screen the specific potential biomarkers,metabolic pathways and to explore the possible mechani-sms.RESULTS 48 chemical constituents were identified.Many of them have strong pharmacological activity,the results also revealed that A.japonica significantly improved the pathological damage of gastric tissues,increased the expression levels of IL-10,IκBαrelated to anti-inflammatory factors,decreased the expression levels of IL-1β,NF-κB,NF-κBp65,related to proinflammatory factors,restored the levels of factors about EGF,EGFR,ZO-1 associated with ulcer healing and the levels of factors about NKA associated with energy metabolism.Metabolomic analysis identified 10 potential differential metabolites and enriched 7 related metabolic pathways.CONCLUSION These findings contribute to the understanding of the potential mechanism of A.japonica to improve acetic acidinduced GU,and will be of great importance for the development and clinical application of natural drugs related to A.japonica.展开更多
As an important organic,isobutyl acetate(IbAc)has been widely used in industries because of its good biodegradability,low surface tension,and other properties.The industrial production of IbAc is usually catalyzed by ...As an important organic,isobutyl acetate(IbAc)has been widely used in industries because of its good biodegradability,low surface tension,and other properties.The industrial production of IbAc is usually catalyzed by sulfuric acid.However,the use of sulfuric acid has the drawbacks of causing considerable corrosion to equipment and being difficult to be separated.In this work,n-sulfopropyl-3-methylpyridinium trifluoromethanesulfonate([HSO_(3)-PMPY][CF_(3)SO_(3)])Bronsted acidic ionic liquid(BAIL)was used as the catalyst and the catalytic activity,solubility,and corrosiveness were evaluated for the esterification of acetic acid with isobutanol.The reaction kinetics and chemical equilibrium were systemically studied.Compared to conventional acid catalysts,[HSO_(3)-PMPY][CF_(3)SO_(3)]showed higher catalytic activity,more excellent reusability,more favorable phase separation,and non-corrosiveness.Three kinetic equations based on ideal homogeneous(IH),non-ideal homogeneous(NIH),and modified nonideal homogeneous(NIH-M)models were established and correlated with the experimental data to determine the parameters and errors.The NIH-M model exhibited the best agreement with the experimental data,owing to its prediction considering the non-ideality and the self-catalysis effect of acetic acid in this system.Besides,the error of NIH-M model fitting was mainly caused by the difference in solubility between[HSO_(3)-PMPY][CF_(3)SO_(3)]with reactants and products in the reaction system.Furthermore,the applicability of the NIH-M model was investigated by simulating the esterification of acetic acid with three short-chain alcohols(ethanol,n-butanol,and isobutanol)catalyzed by BAILs.The NIH-M model displayed an acceptable simulation for this type of acetic acid esterification reaction catalyzed by BAILs at different ranges of the BAILs concentration and temperature.This study confirmed the industrial prospects of[HSO_(3)-PMPY][CF_(3)SO_(3)]in isobutyl acetate production and the applicability of the NIH-M kinetic model in the esterification of acetic acid.展开更多
Cobalt methanesulfonate in combination with acetic acid catalysed the chemoselective diacetylation of aldehyde with acetic anhydride at room temperature under solvent free conditions. After reaction, cobalt methanesul...Cobalt methanesulfonate in combination with acetic acid catalysed the chemoselective diacetylation of aldehyde with acetic anhydride at room temperature under solvent free conditions. After reaction, cobalt methanesulfonate can be easily recovered and reused many times. The reaction was mild and efficient with good to high yields.展开更多
<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> It is not well analyze...<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> Ultra high-speed </span></span><span style="font-family:""><span style="font-family:Verdana;">liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive </span><span><span style="font-family:Verdana;">patients. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.展开更多
AIM: To determine whether the endoscopic findings of depressed-type early gastric cancers(EGCs) could precisely predict the histological type.METHODS: Ninety depressed-type EGCs in 72 patients were macroscopically and...AIM: To determine whether the endoscopic findings of depressed-type early gastric cancers(EGCs) could precisely predict the histological type.METHODS: Ninety depressed-type EGCs in 72 patients were macroscopically and histologically identified. We evaluated the microvascular(MV) and mucosal surface(MS) patterns of depressed-type EGCs using magnifying endoscopy(ME) with narrow-band imaging(NBI)(NBI-ME) and ME enhanced by 1.5% acetic acid, respectively. First, depressed-type EGCs were classified according to MV pattern by NBI-ME. Subsequently, EGCs unclassified by MV pattern were classified according to MS pattern by enhanced ME(EME) images obtained from the same angle.RESULTS: We classified the depressed-type EGCs into the following 2 MV patterns using NBI-ME: a fine-network pattern that indicated differentiated adenocarcinoma(25/25, 100%) and a corkscrew pattern that likely indicated undifferentiated adenocarcinoma(18/23, 78.3%). However, 42 of the 90(46.7%) lesions could not be classified into MV patterns by NBI-ME. These unclassified lesions were then evaluated for MS patterns using EME, which classified 33(81.0%) lesions as MS patterns, diagnosed as differentiated adenocarcinoma. As a result, 76 of the 90(84.4%) lesions were matched with histological diagnoses using a combination of NBI-ME and EME.CONCLUSION: A combination of NBI-ME and EME was useful in predicting the histological type of depressedtype EGC.展开更多
AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy.
The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of var...The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.展开更多
A new separation method, reactive extractive distillation, was put forward for separating water and acetic acid. The separation mechanism was analyzed through infrared spectra technique. Isobaric vapor-liquid equilibr...A new separation method, reactive extractive distillation, was put forward for separating water and acetic acid. The separation mechanism was analyzed through infrared spectra technique. Isobaric vapor-liquid equilibrium (VLE) data at 101.33 kPa for the binary or ternary systems consisting of water, acetic acid and tributylamine were measured. The activity coefficients were correlated by using Wilson, NRTL, and UNIQUAC Equations.The VLE experiment showed that tributylamine could enhance the relative volatility of water to acetic acid. An extractive distillation experiment was carried out and proved that tributylamine was a good extractive solvent.展开更多
AIM To study the short term effect of Danshen ( Salvia miltiorrhiza ) on acetic acid induced chronic gastric ulcer in rats and its long term effect in preventing recurrence. METHODS Rats with acetic acid indu...AIM To study the short term effect of Danshen ( Salvia miltiorrhiza ) on acetic acid induced chronic gastric ulcer in rats and its long term effect in preventing recurrence. METHODS Rats with acetic acid induced gastric ulcer were treated with Danshen and cimetidine for 30 days. Traditional gastric mucosal auto radiography and 3H TdR incorporation into gastric mucosa in vitro were employed to study the effects of Danshen in rat acetic acid induced chronic gastric ulcer, including ulcer index (UI), ulcer inhibitory rate (IR) and label rate (LR). RESULTS On the day 5, 30 and 126 of ulcer making, the UI in the Danshen group was obviously lower than that in the cimetidine group and the control group (42 3±3 9, 3 6±1 2, 4 4±2 3; 49 1±3 6, 5 9±1 4, 9 2±1 3; 61 0±3 8, 8 9±2 5, 12 4±2 4, respectively, P <0 01), the IR (%) in the Danshen group was obviously higher than that in the cimetidine group (31, 59, 64 8; 19, 33, 26, respectively), and the LR in the Danshen group was obviously higher than that in the cimetidine group and the control group (10 0±0 5, 16 2±0 8, 15 0±0 6; 9 0±0 5, 13 9±0 6, 10 8±0 7; 6 5±0 7, 10 1±0 5, 8 0±0 7, respectively, P <0 01). There was no obvious difference in UI in the Danshen group on day 30 as compared with that on day 126. CONCLUSION Danshen is effective in promoting ulcer healing and preventing recurrence. The mechanism of action is to strengthen the gastric mucosal barrier and to promote the gastric mucosal cell proliferation along the edge of the ulcer.展开更多
Ru catalysts, supported on TiO 2 , CeO 2 , and CeO 2 -TiO 2 , were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was investigated in the catalytic wet...Ru catalysts, supported on TiO 2 , CeO 2 , and CeO 2 -TiO 2 , were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was investigated in the catalytic wet air oxidation (CWAO) of acetic acid under 230℃ and 5 MPa in a batch reactor. Physical properties including the surface area, crystalline phase, and surface components of the Ru catalysts were characterized by N 2 adsorption, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The CeO 2 -based Ru catalysts had good activity, and the prepared RuO 2 /CeO 2 catalyst showed markedly higher activity than the RuO 2 /CeO 2 -TiO 2 catalyst. The surface structure, the high amount of chemisorbed oxygen on the catalyst surface, and the suitable pH pzc value of the supports played an important role in the activity of the Ru catalysts in CWAO of acetic acid.展开更多
The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilib...The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.展开更多
In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid (DTPA) supported on K10 montmorillonite was systematically studied and optimization of process parameters wa...In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid (DTPA) supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried out.The 20% m/m DTPA/K10 was found to be the optimum catalyst with 90% acetic acid conversion and 100% ethyl acetate selectivity.The study was also explored to see the feasibility of 20% m/m DTPA/K10 as a catalyst for the alkylation of acetic acid with other alcohols like methanol,iso-propanol and n-butanol.The 20% m/m DTPA/K10 has shown increased activity with the increase in carbon number,at the same alcohol reflux.The results are novel.展开更多
Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scann...Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.展开更多
基金supported by the National Key Research and Development Program of China(2021YFC2101303)the National Natural Science Foundation of China(U22A20424 and 22378048)+6 种基金the Major Scientific and Technological Projects of Sinopecthe Dalian Technology Talents Project for Distinguished Young Scholars(2021RJ03)the Yunnan Provincial Rural Energy Engineering Key Laboratory(2022KF003)the National Natural Science Foundation of Liaoning Province(2023-MS-110)the Liaoning Revitalization Talents Program(XLYC2202049)the Fundamental Research Funds for the Central Universities(DUT22LK22)the CAS Key Laboratory of Renewable Energy,Guangzhou Institute of Energy Conversion(E229kf0401)。
文摘Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production.They negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae strains.Development of industrial S.cerevisiae strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol production.In this study,the acetic acid or furfural tolerance of different S.cerevisiae strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress conditions.The acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^(-1)ethanol with a yield of 0.46 g·g^(-1)in the presence of 9 g·L^(-1)acetic acid,while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^(-1)with increased yield up to 0.49 g·g^(-1)in the presence of both 9 g·L^(-1)acetic acid and 4 g·L^(-1)furfural.Significant improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94,which achieved ethanol production and yield of 29.1 g·L^(-1)and 0.49 g·g^(-1),respectively,the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95%higher than those of wildtype strains,indicating the acetic acid-and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol production.The adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.
基金supported by National Natural Science Foundation of China(51876080)the Program for Taishan Scholars of Shandong Province Government,the Agricultural Innovation Program of Shandong Province(SD2019NJ015)+1 种基金the Research and Development program of Shandong Basan Graphite New Material Plant,National Natural Science Foundation of China(52076097)Key projects for inter-governmental cooperation in international science,technology and innovation(2018YFE0127500).
文摘Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as two comparative catalysts,Ni/Al_(2)O_(3) and Ni/SiO_(2),with low nickel loading(2%(mass))was conducted to probe involvement of the varied carriers in the steam reforming.The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO_(2) and Ni/Al_(2)O_(3),as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C,resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance.In converse,strong adsorption of aliphatic intermediates over Ni/Al_(2)O_(3) and Ni/SiO_(2) induced serious coking with polymeric coke as the main type(21.5%and 32.1%,respectively),which was significantly higher than that over Ni/biochar(3.9%).The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity.The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam,which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al_(2)O_(3) and Ni/SiO_(2) catalysts.
文摘Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution(4%v/v)in rats.Rats were divided into six groups including the sham group,the negative control group,the dexamethasone-treated group,and the groups treated with isoimperatorin(0.1,1,and 10 mg/kg/d by gavage).The treatments were administered for three days and then colonic status was assessed by macroscopic,histopathological,and biochemical analyses.Results:Isoimperatorin significantly alleviated colonic damage in a dose-dependent manner and improved histological changes in rats with acetic acid-induced colitis.It also significantly reduced myeloperoxidase,TNF-α,IL-1β,and malodialdehyde levels.Conclusions:Isoimperatorin alleviates acetic acid-induced colitis in rats and may be a potential therapeutic agent for the treatment of colitis.
基金the China Scholarship Council(CSC)for funding(no.201806310116)。
文摘Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.
文摘BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.
文摘BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capillary network,and gastric pits.AIM To evaluate the effectiveness of a new one-dual(near)focus,NBI mode in the assessment of the microscopic features of gastric body mucosa compared to conventional magnification.METHODS During 2021 and 2022,68 patients underwent proximal gastrointestinal endoscopy using magnification endoscopic modalities subsequently applying acetic acid(AA).The GIF-190HQ series NBI system with dual focus capability was used for the investigation of gastric mucosa.At the time of the endoscopy,the gastric body mucosa of all enrolled patients was photographed using the white light endoscopy(WLE),near focus(NF),NF-NBI,AA-NF,and AA-NF-NBI modes.RESULTS The WLE,NF and NF-NBI endoscopic modes for all patients(204 images)were classified in the same order into three groups.Two images from each patient for the AA-NF and AA-NF-NBI endoscopic modes were classified in the same order.According to all three observers who completed the work independently,NF magnification was significantly superior to WLE(P<0.01),and the NF-NBI mode was significantly superior to NF magnification(P<0.01).After applying AA,the three observers confirmed that AA-NF-NBI was significantly superior to AA-NF(P<0.01).Interobserver kappa values for WLE were 0.609,0.704,and 0.598,respectively and were 0.600,0.721,and 0.637,respectively,for NF magnification.For the NF-NBI mode,the values were 0.378,0.471,and 0.553,respectively.For AA-NF,they were 0.453,0.603,and 0.480,respectively,and for AA-NF-NBI,they were 0.643,0.506,and 0.354,respectively.CONCLUSION When investigating gastric mucosa in microscopic detail,NF-NBI was the most powerful endoscopic mode for assessing regular arrangement of collecting venules,subepithelial capillary network,and gastric pits among the five endoscopic modalities investigated in this study.AA-NF-NBI was the most powerful endoscopic mode for analyzing crypt opening and intervening part.
文摘It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and countermeasures were needed. Therefore, we studied the copper corrosion caused by acetic acid. The present work investigated the relationship between the corrosion form of copper and acetic acid concentration using phosphorous-deoxidized copper, and reported that hemispherical corrosion was observed at acetic acid concentrations of 0.01 to 1 vol.% (0.002 to 0.2 mol·L<sup>-1</sup>) in the immersion test. In this study, the effects of acetic acid and phosphate on copper corrosion were examined using oxygen-free copper in immersion tests. The results suggested that different concentrations of phosphate in acetic acid solutions and the presence or absence of acetic acid and phosphate affected the corrosion of copper, resulting in different corrosion forms and corrosion progress.
基金Supported by National Natural Science Foundation of China,No.81973478Liaoning Revitalization Talents Program,China,No.XLYC2002004Natural Science Foundation of Liaoning Province,China,No.2019-ZD-0443.
文摘BACKGROUND Atractylodes japonica Koidz.ex Kitam.(A.japonica,Chinese name:Guan-Cangzhu,Japanese name:Byaku-jutsu),a perennial herb,which is mainly distributed in northeast area of China,it’s often used to treat digestive system diseases such as gastric ulcer(GU).However,the mechanism of its potential protective effects against GU remains unclear.AIM To investigate the protective effects of A.japonica on acetic acid-induced GU rats.METHODS The chemical constituents of A.japonica were determined by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)analysis.The rat model of GU was simulated by acetic acid method.The pathological changes of gastric tissues were evaluated by hematoxylin-eosin stain,the levels of epidermal growth factor(EGF),EGF receptor(EGFR),nuclear factor kappa-B(NF-κB),interleukin-1β(IL-1β),IL-10,Na^(+)-K^(+)-ATPase(NKA)in serum and gastric tissues were determined by enzyme-linked immunosorbent assay,and the mRNA expressions of EGFR,NF-κBp65,IkappaBalpha(IκBα)and Zonula Occludens-1(ZO-1)in gastric tissues were determined by real-time reverse transcription polymerase chain reaction,and the efficacy was observed.Then,plasma metabolomic analysis was performed by UPLC-MS/MS to screen the specific potential biomarkers,metabolic pathways and to explore the possible mechani-sms.RESULTS 48 chemical constituents were identified.Many of them have strong pharmacological activity,the results also revealed that A.japonica significantly improved the pathological damage of gastric tissues,increased the expression levels of IL-10,IκBαrelated to anti-inflammatory factors,decreased the expression levels of IL-1β,NF-κB,NF-κBp65,related to proinflammatory factors,restored the levels of factors about EGF,EGFR,ZO-1 associated with ulcer healing and the levels of factors about NKA associated with energy metabolism.Metabolomic analysis identified 10 potential differential metabolites and enriched 7 related metabolic pathways.CONCLUSION These findings contribute to the understanding of the potential mechanism of A.japonica to improve acetic acidinduced GU,and will be of great importance for the development and clinical application of natural drugs related to A.japonica.
基金supported by the National Natural Science Foundation of China(22168004)the Natural Science Foundation of Guangxi Province(2017GXNSFDA198047)the Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2019Z010,2021Z013)。
文摘As an important organic,isobutyl acetate(IbAc)has been widely used in industries because of its good biodegradability,low surface tension,and other properties.The industrial production of IbAc is usually catalyzed by sulfuric acid.However,the use of sulfuric acid has the drawbacks of causing considerable corrosion to equipment and being difficult to be separated.In this work,n-sulfopropyl-3-methylpyridinium trifluoromethanesulfonate([HSO_(3)-PMPY][CF_(3)SO_(3)])Bronsted acidic ionic liquid(BAIL)was used as the catalyst and the catalytic activity,solubility,and corrosiveness were evaluated for the esterification of acetic acid with isobutanol.The reaction kinetics and chemical equilibrium were systemically studied.Compared to conventional acid catalysts,[HSO_(3)-PMPY][CF_(3)SO_(3)]showed higher catalytic activity,more excellent reusability,more favorable phase separation,and non-corrosiveness.Three kinetic equations based on ideal homogeneous(IH),non-ideal homogeneous(NIH),and modified nonideal homogeneous(NIH-M)models were established and correlated with the experimental data to determine the parameters and errors.The NIH-M model exhibited the best agreement with the experimental data,owing to its prediction considering the non-ideality and the self-catalysis effect of acetic acid in this system.Besides,the error of NIH-M model fitting was mainly caused by the difference in solubility between[HSO_(3)-PMPY][CF_(3)SO_(3)]with reactants and products in the reaction system.Furthermore,the applicability of the NIH-M model was investigated by simulating the esterification of acetic acid with three short-chain alcohols(ethanol,n-butanol,and isobutanol)catalyzed by BAILs.The NIH-M model displayed an acceptable simulation for this type of acetic acid esterification reaction catalyzed by BAILs at different ranges of the BAILs concentration and temperature.This study confirmed the industrial prospects of[HSO_(3)-PMPY][CF_(3)SO_(3)]in isobutyl acetate production and the applicability of the NIH-M kinetic model in the esterification of acetic acid.
文摘Cobalt methanesulfonate in combination with acetic acid catalysed the chemoselective diacetylation of aldehyde with acetic anhydride at room temperature under solvent free conditions. After reaction, cobalt methanesulfonate can be easily recovered and reused many times. The reaction was mild and efficient with good to high yields.
文摘<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> Ultra high-speed </span></span><span style="font-family:""><span style="font-family:Verdana;">liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive </span><span><span style="font-family:Verdana;">patients. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.
文摘AIM: To determine whether the endoscopic findings of depressed-type early gastric cancers(EGCs) could precisely predict the histological type.METHODS: Ninety depressed-type EGCs in 72 patients were macroscopically and histologically identified. We evaluated the microvascular(MV) and mucosal surface(MS) patterns of depressed-type EGCs using magnifying endoscopy(ME) with narrow-band imaging(NBI)(NBI-ME) and ME enhanced by 1.5% acetic acid, respectively. First, depressed-type EGCs were classified according to MV pattern by NBI-ME. Subsequently, EGCs unclassified by MV pattern were classified according to MS pattern by enhanced ME(EME) images obtained from the same angle.RESULTS: We classified the depressed-type EGCs into the following 2 MV patterns using NBI-ME: a fine-network pattern that indicated differentiated adenocarcinoma(25/25, 100%) and a corkscrew pattern that likely indicated undifferentiated adenocarcinoma(18/23, 78.3%). However, 42 of the 90(46.7%) lesions could not be classified into MV patterns by NBI-ME. These unclassified lesions were then evaluated for MS patterns using EME, which classified 33(81.0%) lesions as MS patterns, diagnosed as differentiated adenocarcinoma. As a result, 76 of the 90(84.4%) lesions were matched with histological diagnoses using a combination of NBI-ME and EME.CONCLUSION: A combination of NBI-ME and EME was useful in predicting the histological type of depressedtype EGC.
文摘AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy.
基金Supported by the R&D center of Esfahan refinery (Esfahan,Iran)the technical supports of central laboratory of Esfahan Refinery for total sulfur analysis
文摘The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.
文摘A new separation method, reactive extractive distillation, was put forward for separating water and acetic acid. The separation mechanism was analyzed through infrared spectra technique. Isobaric vapor-liquid equilibrium (VLE) data at 101.33 kPa for the binary or ternary systems consisting of water, acetic acid and tributylamine were measured. The activity coefficients were correlated by using Wilson, NRTL, and UNIQUAC Equations.The VLE experiment showed that tributylamine could enhance the relative volatility of water to acetic acid. An extractive distillation experiment was carried out and proved that tributylamine was a good extractive solvent.
文摘AIM To study the short term effect of Danshen ( Salvia miltiorrhiza ) on acetic acid induced chronic gastric ulcer in rats and its long term effect in preventing recurrence. METHODS Rats with acetic acid induced gastric ulcer were treated with Danshen and cimetidine for 30 days. Traditional gastric mucosal auto radiography and 3H TdR incorporation into gastric mucosa in vitro were employed to study the effects of Danshen in rat acetic acid induced chronic gastric ulcer, including ulcer index (UI), ulcer inhibitory rate (IR) and label rate (LR). RESULTS On the day 5, 30 and 126 of ulcer making, the UI in the Danshen group was obviously lower than that in the cimetidine group and the control group (42 3±3 9, 3 6±1 2, 4 4±2 3; 49 1±3 6, 5 9±1 4, 9 2±1 3; 61 0±3 8, 8 9±2 5, 12 4±2 4, respectively, P <0 01), the IR (%) in the Danshen group was obviously higher than that in the cimetidine group (31, 59, 64 8; 19, 33, 26, respectively), and the LR in the Danshen group was obviously higher than that in the cimetidine group and the control group (10 0±0 5, 16 2±0 8, 15 0±0 6; 9 0±0 5, 13 9±0 6, 10 8±0 7; 6 5±0 7, 10 1±0 5, 8 0±0 7, respectively, P <0 01). There was no obvious difference in UI in the Danshen group on day 30 as compared with that on day 126. CONCLUSION Danshen is effective in promoting ulcer healing and preventing recurrence. The mechanism of action is to strengthen the gastric mucosal barrier and to promote the gastric mucosal cell proliferation along the edge of the ulcer.
基金supported by the National Natural Science Foundation of China (No. 51078143)the National High Technology Research & Development Program of China (No. 2002AA601260)
文摘Ru catalysts, supported on TiO 2 , CeO 2 , and CeO 2 -TiO 2 , were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was investigated in the catalytic wet air oxidation (CWAO) of acetic acid under 230℃ and 5 MPa in a batch reactor. Physical properties including the surface area, crystalline phase, and surface components of the Ru catalysts were characterized by N 2 adsorption, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The CeO 2 -based Ru catalysts had good activity, and the prepared RuO 2 /CeO 2 catalyst showed markedly higher activity than the RuO 2 /CeO 2 -TiO 2 catalyst. The surface structure, the high amount of chemisorbed oxygen on the catalyst surface, and the suitable pH pzc value of the supports played an important role in the activity of the Ru catalysts in CWAO of acetic acid.
基金Supported by the Major State Basic Research Development Program of China (2012CB720500), the National Natural Science Foundation of China (U1162202, 61174118) and the Shanghai Leading Academic Discipline Project (B504).
文摘The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.
文摘In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid (DTPA) supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried out.The 20% m/m DTPA/K10 was found to be the optimum catalyst with 90% acetic acid conversion and 100% ethyl acetate selectivity.The study was also explored to see the feasibility of 20% m/m DTPA/K10 as a catalyst for the alkylation of acetic acid with other alcohols like methanol,iso-propanol and n-butanol.The 20% m/m DTPA/K10 has shown increased activity with the increase in carbon number,at the same alcohol reflux.The results are novel.
文摘Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.