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1.
为提高2,6-二羟基苯甲酸的合成收率,采用有机溶剂法制备了2,6-二羟基苯甲酸。探讨了溶剂种类,催化剂种类及用量,反应温度,反应压力及反应时间对产品收率的影响。确定以N,N-二甲基甲酰胺(DMF)为溶剂、K2CO3为催化剂,在140℃、10 atm压力下反应6 h,2,6-二羟基苯甲酸的单程收率可达35%以上,产品纯度95%以上。 相似文献
2.
研究了以2,6-二羟基对苯二甲酸(2,6-DH-TA)与4-氨基-6-硝基间苯二酚盐酸盐(ANR·HCl)为原料经酰氯化和N-酰化一锅法及环合等一系列反应合成得到中间体4-[(2,4-二羟基-5-硝基苯基)氨甲酰基]-2,6-二羟基苯甲酸(2,6-DH-NCA)和2,6-二羟基改性PBO的AB型酸类新单体的关键前体4-(6-羟基-5-硝基-2-苯并唑基)-2,6-二羟基苯甲酸(2,6-DH-NBA),并对其反应条件进行了优化。结果表明:对于酰氯化和N-酰化一锅法反应,以1,4-二氧六环为酰氯化溶剂,SOCl2为酰氯化试剂,酰氯化时间2h,N-酰化溶剂为4-甲基2-戊酮,N-酰化温度105℃,N-酰化时间4h,N-酰化缚酸剂为三乙胺,n(2,6-DH-TA):n(ANR·HCl):n(SOCl2):n(三乙胺)=1.0:1.0:2.0:0.5,经乙醇精制,2,6-DH-NCA收率80.31%,HPLC纯度(质量分数)98.57%;环合反应,以二乙二醇二甲醚为溶剂,多聚磷酸(PPA)为脱水剂,PPA中P2O5质量含量85%,w(2,6-DH-NCA):w(PPA)=1:8.6,反应温度135℃,反应时间6h,2,6-DH-NBA收率83.76%,HPLC纯度99.25%。中间体和产物结构经FTIR、1H NMR和EI-MS表征确认。 相似文献
3.
Masahiro Takehara Ippei Yoshimura Kouichi Takizawa Ryonosuke Yoshida 《Journal of the American Oil Chemists' Society》1972,49(3):157-161
Long chain N-acylglutamic acid was prepared in a high yield by a reaction of glutamic acid with fatty acid chloride in a mixed
solvent of water and a water miscible organic solvent such as acetone, methyl ethyl ketone, dioxane, tetrahydrofuran,t-butyl alcohol or cyclohexanone. In this reaction the composition of the mixed solvent influenced the yield of N-acylated
glutamic acid and the best yield was obtained when the reaction was carried out in the mixed solvent comprising 30–60% v/v
of the organic solvent. Long chain N-acylaspartic acid was also obtained in a high yield by the same method. As the other
method to obtain N-lauroyl-D L-glutamic acid, it was examined that N-acyl-α-aminoglutarodinitrile which was obtained by a reaction of α-aminoglutarodinitrile
with fatty acid chloride was hydrolyzed with an aqueous alkaline solution. The salts of long chain N-acylglutamic acid are
known as the surface active agents that react mildly on the human skin. 相似文献
4.
Silica was extracted from rice husk (RH) and modified with ruthenium and amino benzoic acid. The catalysts RH–Ru and RH–Ru–A
(incorporated with 5% of 4-(methylamino)benzoic acid) were synthesized from rice husk via solvent extraction and sol–gel technique.
XRD diffractogram showed both catalysts were amorphous. BET results showed that the surface area of RH–Ru–A (73.9 m2 g−1) was smaller compared with RH–Ru (138 m2 g−1). After calcinations at 700 °C, RH–Ru-700 and RH–Ru–A-700 showed a lower specific surface area, i.e. 21.8 and 19.0 m2 g−1, respectively. The SEM micrograph of RH–Ru-700 showed the presence of elongated nano fibers, while RH–Ru–A-700 showed the
presence of large regular pore structures. RH–Ru and RH–Ru–A were used as catalyst for the oxidation of 1-butanol with molecular
oxygen as the oxidant. The oxidation yielded only one product, i.e. 1-butanal. Although the yield of 1-butanal was less than
10% both catalyst showed great potential for the oxidation of primary alcohols into aldehydes at moderate reaction conditions.
A plausible mechanism was suggested for the catalyzed oxidation. 相似文献
5.
Wei Zhao Petra Salame Virginie Herledan Franck Launay Antoine Gédéon Tao Qi 《Journal of Porous Materials》2010,17(3):335-340
Hybrid inorganic–organic solid acid material SBA-15-Ph–SO3H was synthesized by the co-condensation of tetraethoxysilane and 2-(4-chlorosulfonylphenyl) ethyltrimethoxysilane in the
presence of a Poly (alkylene oxide) block copolymer under acid conditions. The catalytic activity of the obtained materials
was studied in liquid-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. The results show that there exists
an obvious “Solvent effect” in this reaction system and the strong Bronsted acid is proofed again to be at the origin of the
formation of ε-caprolactam. Moreover, we tentatively proposed a reaction mechanism involving a five-member ring intermediate
product when toluene was used as solvent. 相似文献
6.
A series of novel soluble aromatic polyamides with pendant cyano groups were synthesized by low temperature polycondensation
of aromatic diamines with a new monomer 2,6-bis(4-chloroformylphenoxy)benzonitrile (ClPOBN) in the presence of N,N-dimethylacetamide (DMAC) as the solvent and tertiary amines as the absorbent of HCl. The properties and structures of obtained
polymers were characterized by means of FTIR, TG, and elemental analysis. Structures of prepared polymers are as expected.
TG studies show that the polymers had excellent thermal stability as measured by 5% weight loss temperatures in nitrogen (409–438 °C).They
are soluble in aprotic polar organic solvents such as N-methyl pyrrolidone (NMP), dimethyl sulphoxide (DMSO) and N,N-dimethylformamides (DMF) and are swelled in common solvents, such as CHCl3, ethylene dichloride (DCE), CH2Cl2, tetrahydrofuran (THF), etc. Their thin films which cast from DMF had tensile strength of 79–93 MPa, Young’s moduli of 1.7–2.6 GP,
elongation at break of 9–15%, indicating they are strong in mechanical properties. 相似文献
7.
Summary Optically active liquid crystalline side chain polymers with dif ferent flexible spacer groups (n=2–11) and different main
chains (acry lates, methacrylates and α chloroacrylates) are described. (+)-2-methyl butyloxyphenyl esters of benzoic acid
were chosen as the mesogenic group. 相似文献
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9.
以柠康酸酐和盐酸联氨为起始原料,经过三步反应制得3,6-二氯哒嗪-4-羧酸。通过红外、核磁共振对其结构进行了确证。考察了原料用量、氧化剂种类以及用量、反应温度、反应时间等对合成3,6-二氯哒嗪-4-羧酸的影响。较佳工艺条件为:合成3,6-二羟基-4-甲基哒嗪时,柠康酸酐和盐酸联氨摩尔比为1∶1.12;氯代反应时,3,6-二羟基-4-甲基哒嗪和三氯氧磷摩尔比为1∶6。以HNO3-KClO3为氧化剂,其与3,6-二氯-4-甲基哒嗪质量比为2∶1,在35~40℃反应3 h。总收率达到52%,纯度大于98%。 相似文献
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12.
D. B. Mahadik A. Venkateswara Rao Ratanesh Kumar S. V. Ingale P. B. Wagh Satish C. Gupta 《Journal of Porous Materials》2012,19(1):87-94
The present paper deals with preparation of silica aerogel granules by two step acid–base sol–gel process involving ambient
pressure drying of alcogels with additional use of mechanical shaker to accelerate the solvent exchange process and characterization
of the yielded aerogels granules to study their physical properties. The conventional ambient pressure drying of alcogels
is crucial since it needs tedious repetitive gel washing and solvent exchanges (10 times) which consumes total process time
of 4 days. We have succeeded to synthesize aerogels within 2 days by making use of alcogels shaking. To get good quality aerogels
in terms of low density, high optical transparency, low volume shrinkage, various base catalysts and their combinations were
used. The optimal molar ratio of precursor chemicals Tetraethoxysilane (TEOS): Methanol (MeOH): Oxalic acid: NH4OH: NH4F: Trimethylchlorosilane (TMCS) found to be 1: 16.5: 0.49: 0.58: 0.60: 0.98, respectively. Among six catalyst studied, combination
of NH4OH and NH4F resulted in low density and transparent aerogels. Hydrophobicity was achieved by surface silylation using TMCS silylating
agent but lead to decrease in transparency due to chloride precipitation. We have improved transparency of aerogels by methanol
washing of alcogels prior to silylation. The hydrophobicity has been studied by FTIR analysis and contact angle measurements.
The thermal analysis indicates thermal stability of hydrophobicity up to 318 °C and the Surface morphology of aerogel has
been studied by FESEM. 相似文献
13.
Titania and titania–silica aerogels were prepared by alkoxide or non-alkoxide sol–gel route and subsequent supercritical drying
with carbon dioxide at low temperature. The resulting aerogels having high surface area and mesoporosity were used as photocatalysts
for gas phase methanol degradation reaction. Photocatalytic degradation reactions were carried out on titania and titania–silica
aerogels, and commercial Degussa P-25 titania. The photocatalytic activities of titania and titania–silica aerogels were higher
than that of the P-25. While the conversion of methanol degradation over the P-25 catalyst was only 50–60%, that for the titania
aerogel was observed to be above 98% due to the higher specific surface area and the well developed mesoporous structure.
In spite of lower titania contents, much higher surface area and high dispersion of titania of titania–silica aerogel gave
rise to the high photocatalytic activity in comparison to those of titania aerogels. Moreover, titania–silica aerogel was
also used for the photodegradation and adsorption hybrid system. It was observed that the high removal efficiency for methanol
was caused by the combination of higher catalytic activity and adsorption capacity. 相似文献
14.
研究了以2,6-二羟基-1-甲酯-1,4-苯二酸(α酯)与4-氨基-6-硝基间苯二酚盐酸盐(ANR·HCl)为原料经酰氯化、N-酰化、环合和催化加氢还原等一系列反应合成得到中间体4-[(2,4-二羟基-5-硝基苯基)氨甲酰基]-2,6-苯甲酸甲酯(2,6-DH-MNC)和4-(6-羟基-5-硝基-2-苯并 唑基)-2,6-苯甲酸甲酯(2,6-DH-MNB)及2,6-二羟基改性PBO的AB型新单体4-(5-氨基-6-羟基-2-苯并 唑基)-2,6-二羟基苯甲酸甲酯(2,6-DH-MAB),并对环合和催化还原加氢的反应条件进行了优化。结果表明:对于环合反应,以二乙二醇二甲醚为溶剂,多聚磷酸(PPA)为脱水剂,PPA中P2O5质量分数83%,w(2,6-DH-MNC):w(PPA)=1:6,反应温度140℃,反应时间8h,2,6-DH-MNB收率74.15%,HPLC纯度98.76%;催化加氢还原反应,以N,N-二甲基甲酰胺(DMF)为溶剂,w(5%Pd/C):w(2,6-DH-MNB)=1:20,氢气压力0.5~1MPa和温度60℃下反应3h得到2,6-DH-MAB,HPLC纯度99.69%,收率81.42%。中间体和产物结构经FT-IR、13C NMR、1H NMR和ESI-MS表征确认。 相似文献
15.
The removal of low-molecular-weight benzoic acid (benzoic acid, p-toluic acid, and salicylic acid)-derived and aniline (aniline, 4-chloroaniline, and 2,6-dimethylaniline)-derived organic compounds through adsorptive micellar flocculation (AMF) with anionic surfactants (sodium dodecyl sulfate, SDS) and aluminum sulfate was demonstrated. The interactions between SDS and the organic compounds were studied using 1H nuclear magnetic resonance (NMR) spectroscopy. Batch AMF experiments were conducted to study the influence of several factors on target pollutant removal. For benzoic acid derivatives, the removal rate was improved by increasing the SDS and Al concentrations, while increases in the concentrations of the organic pollutant tended to decrease the removal rate. The highest removal efficiencies were observed with p-toluic acid (95.4%) > salicylic acid (84.5%) > benzoic acid (76.5%) under weakly acidic conditions due to the greater hydrophobicity of p-toluic acid and the complexation of the Al salts and the salicylic acid. The removal rates of the aniline derivatives were positively related to the SDS concentration and negatively related to the pH. At a pH of 3.0, the highest removal rates of aniline, 4-chloroaniline, and 2,6-dimethylaniline (91.3%, 98.0%, and 97.6%, respectively) were observed. For aniline compounds, charge neutralization between the SDS anions and aniline cations dominated the removal process. These findings provide new insights for the development of further applications of AMF for the removal of benzoic acid and aniline derivatives. 相似文献
16.
Paola Catalfamo Letterio Mavilia Patrizia Primerano Francesco Corigliano 《Journal of Porous Materials》2007,14(3):285-289
Ascorbic acid is commonly used as an antioxidant agent in form of a powder. This allows the immediate availability of the
molecule but cannot avoid the rapid inactivation of the excess. Sodium zeolites have frequently been proposed as agents for
the controlled release of absorbed molecules. In order to prepare controlled release antioxidant agents, we treated sodium
X and Y zeolites with ascorbic acid dissolved in organic solvents in order to establish how much acid they were able to retain
and understand the retention and release mechanism. We found that the acid: (i) undergoes a dissociation and H+/Na+ exchange with zeolite; (ii) is retained as sodium salt while the zeolite is protonated; (iii) is released as a function of
the sodium salt solubility into the solvent used. Thus, the imbibition was function of the nature of the solvent and, in aqueous-organic
solvent mixtures, it was a direct function of the water concentration in the range 0–1% and an inverse function in the range
1–11%. It follows from above that, when sodium zeolite is used as a support for ascorbic acid, water percent in the range
0–11% may control the release as the ascorbate salt into aqueous–organic solvent mixtures. 相似文献
17.
In this work, adsorption and crystallization of benzoic acid in different porous carriers (silica aerogel, MCM41, Trisopor glass, zeolite) from supercritical CO2 solutions is studied. The main purpose is to reveal the influence of the adsorptive properties of the carrier on the crystallization behavior of the solute. Therefore, both adsorption and crystallization processes are studied as a function of carrier's surface properties. Adsorption of the solute and CO2 is measured in situ using a magnetic suspension balance, whereas crystallization is realized in a high pressure view cell. The carriers could be loaded with up to ∼35 wt.% of benzoic acid, depending on the nature and the amount of the functional groups of the carrier. The size of the benzoic acid particles obtained inside the aerogel matrix depends on the crystallization conditions and is in the range of ∼20 nm-50 μm. The crystallinity of the particles was studied and it is shown that the physical state of the loaded benzoic acid inside the pores of aerogels is influenced by benzoic acid-aerogel surface interactions: strong interactions favor the amorphous form, weak interactions favor crystalline particles. The amorphous form of benzoic acid is shown to be stable over a long time period. Thus, silica aerogels can be used for stabilizing amorphous forms of organic compounds, which can be used for instance in pharmaceutical applications for the improvement of drug bioavailability. 相似文献
18.
Palraj Kasinathan Dong Won Hwang Uhwang Lee Young Kyu Hwang Jong-San Chang 《Chemical engineering science》2011,(20):4549
Fermentation-derived ammonium lactate was converted into ethyl lactate by decomposition in various organic solvents followed by esterification with ethanol over Amberlyst catalyst. The ammonium lactate was decomposed more efficiently in an organic solvent with high boiling point, where the produced lactic acid was stabilized well as a monomer without oligomerization. However, only the nonreactive phosphate-type solvent such as triethyl phosphate and tributyl phosphate showed a notable ethyl lactate yield in the subsequent esterification reaction compared with dimethyl sulfoxide and N-methyl pyrolidine. The lactic acid yield in ammonium lactate decomposition and the subsequent ethyl lactate yield were also highly dependent on solvent ratio to ammonium lactate, temperature and pressure in ammonium lactate decomposition reaction. The amino acid impurity contained in the fermented ammonium lactate as well as the unreacted ammonium lactate reduced the acid strength of Amberlyst-36, which resulted in the final ethyl lactate yield. 相似文献
19.
Safaa El-din H. Etaiw Abd El-Aziz S. Fouda Said A. Amer Mohamed M. El-bendary 《Journal of Inorganic and Organometallic Polymers and Materials》2011,21(2):327-335
Yellow crystals of the metal–organic framework (MOF), [Ag(qox)(4-ab)] (1) were obtained at room temperature by the reaction of AgNO3, quinoxaline (qox) and 4-amino benzoic acid (4-aba). A cluster molecule containing two silver atoms, two qox and two 4-ab
ligands is considered the basic building block of the structure of 1. A 3D-network structure is created via H-bonds and π–π stacking. MOF 1 was tested as a corrosion inhibitor for C-steel in 1 M HCl solution using potentiodynamic polarization and electrochemical
impedance techniques. It was found that 1 is rich with electron donating groups and the π-systems exhibiting high inhibition efficiency. The adsorption of 1 obeyed the Freundlich adsorption isotherm. Polarization curves indicate that 1 is mixed-type inhibitor. Activation parameters were calculated and discussed. The results obtained from EIS and potentiodynamic
polarization are in good agreement. 相似文献