Synthesis of anisole by vapor phase methylation of phenol with methanol over catalysts supported on activated alumina

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina（AA） supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield（LAY） has a maximum at 400–450 °C when the temperature varied from 300 to 500°C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O‐methylation and C‐methylation of phenol, a low temperature,high WHSV（short residence time）, and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O‐methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K‐acid＇bifunctional process may be a critical factor to the formation of anisole.

Hydrodeoxygenation of Anisole over Ni/α-Al2O3 Catalyst

Ni-based catalysts supported on di erent supports （α-Al2O3,γ-Al2O3, SiO2, TiO2, and ZrO2） were prepared by impregnation. Effects of supports on catalytic performance were tested using hydrodeoxygenation reaction （HDO） of anisole as model reaction. Ni/α-Al2O3 was found to be the highest active catalyst for HDO of anisole. Under the optimal conditions, the anisole conversion is 93.25% and the hydrocarbon yield is 90.47%. Catalyst characteriza-tion using H2-TPD method demonstrates that Ni/α-Al2O3 catalyst possesses more amount of active metal Ni than those of other investigated catalysts, which can enhance the cat-alytic activity for hydrogenation. Furthermore, it is found that the Ni/α-Al2O3 catalyst has excellent repeatability, and the carbon deposited on the surface of catalyst is negligible.

Effects of Current upon Electrochemical Catalytic Reforming of Anisole

The reforming of anisole （as model compound of bio-oil） was performed over the NiCuZn-Al2O3 catalyst, using a recently-developed electrochemical catalytic reforming （ECR）. The influence of-the current on the anisole reforming in the ECR process has been investigated. It was observed that anisole reforming was significantly enhanced by the current approached over the catalyst in the electrochemical catalytic process, which was due to the non-uniform temperature distribution in the catalytic bed and the role of the thermal electrons originating from the electrified wire. The maximum hydrogen yield of 88.7% with a carbon conversion of 98.3% was obtained through the ECR reforming of anisole at 700℃ and 4 A. X-ray diffraction was employed to characterize catalyst features and their alterations in the anisole reforming. The apparent activation energy for the anisole reforming is calculated as 99.54 kJ/mol, which is higher than ethanol, acetic acid, and light fraction of bio-oil. It should owe to different physical and chemical properties and reforming mechanism for different hydrocarbons.

Catalytic Acylation of Anisole over Some Zeolites

Methoxyacetophenone(4 MAP) was synthesized by the acylation of anisole with acetic anhydride in the presence of HY zeolite. The addition of an appropriate amount of some solvent such as dichloromethane, chloroform, carbon disulfide or chlorobenzene to the reaction system can improve the yield of the acylated product to a certain extent. HY zeolite used can be recovered, and reused after being regenerated, obtaining almost the same yield of 4 MAP as the fresh zeolite.

ZEOLITE－CATALYZED FRIEDEL－CRAFTS ACYLATION OF AROMATICS：I》．SYNTHESIS OF 4－ACYL ANISOLE WITH A HY CATALYST

A series of aromatic ketones 4-acyl anisole were synthesized with high yield by using carboxylic acids as acylating agents and a HY zeolite as catalyst.

Effects of indium on Ni/SiO_2 catalytic performance in hydrodeoxygenation of anisole as model bio-oil compound: Suppression of benzene ring hydrogenation and C–C bond hydrogenolysis

SiO2‐supported monometallic Ni and bimetallic Ni‐In catalysts were prepared and used for hydrodeoxygenation of anisole,which was used as a model bio‐oil compound,for BTX(benzene,toluene,and xylene)production.The effects of the Ni/In ratio and Ni content on the structures and performances of the catalysts were investigated.The results show that In atoms were incorporated into the Ni metal lattice.Although the Ni‐In bimetallic crystallites were similar in size to those of monometallic Ni at the same Ni content,H2uptake by the bimetallic Ni‐In catalyst was much lower than that by monometallic Ni because of dilution of Ni atoms by In atoms.Charge transfer from In to Ni was observed for the bimetallic Ni‐In catalysts.All the results indicate intimate contact between Ni and In atoms,and the In atoms geometrically and electronically modified the Ni atoms.In the hydrodeoxygenation of anisole,although the activities of the Ni‐In bimetallic catalysts in the conversion of anisole were lower than that of the monometallic Ni catalyst,they gave higher selectivities for BTX and cyclohexane as a result of suppression of benzene ring hydrogenation and C–C bond hydrogenolysis.They also showed lower methanation activity.These results will be useful for enhancing carbon yields and reducing H2consumption.In addition,the lower the Ni/In ratio was,the greater was the effect of In on the catalytic performance.The selectivity for BTX was primarily determined by the Ni/In ratio and was little affected by the Ni content.We suggest that the performance of the Ni‐In bimetallic catalyst can be ascribed to the geometric and electronic effects of In.

Hydrodeoxygenation of anisole over different Rh surfaces

The cleavage of the alkoxy(Ar-O-R) ether bond present in anisole is an interesting hydrodeoxygenation(HDO) reaction, since this asymmetric group contains two different C–O bonds, Caryl–O or Calkyl–O, which could potentially cleave. Recent work on the HDO of anisole over Pt, Ru, and Fe catalysts has shown that a common phenoxy surface intermediate is formed on all three metals. The subsequent reaction path of this intermediate varies from metal to metal, depending on the metal oxophilicity. Over the less oxophilic Pt, phenol is the only primary product. By contrast, on the more oxophilic Fe catalyst, the sole primary product is benzene instead of phenol. On Ru, with intermediate oxophilicity, both benzene and phenol are primary products. In this contribution, we have investigated Rh catalysts of varying surface nanostructures. A combination of experimental measurements and computational calculations was used to explore the effects of varying metal coordination number, an additional parameter that can be used to control the oxophilicity of a metal. The results confirm that metal oxophilicity is a good descriptor for HDO performance of metal catalysts and it can be controlled via selection of metal type and/or metal extent of coordination. Small Rh metal clusters with low coordination metal sites are more active for the deoxygenation pathway but also quickly deactivated while large clusters with high coordination sites are more active toward hydrogenation and more stable.

Enhanced hydrodeoxygenation of lignin-derived anisole to arenes catalyzed by Mn-doped Cu/Al_(2)O_(3)

Lignin is a renewable carbon resource to produce arenes due to its abundant aromatic structures.For the liquid-phase hydrodeoxygenation(HDO)based on metallic catalysts,the preservation of aromatic rings in lignin or its derivatives remains a challenge.Herein,we synthesized Mndoped Cu/Al_(2)O_(3) catalysts from layered double hydroxides(LDHs)for liquid-phase HDO of lignin-derived anisole.Mn doping significantly enhanced the selective deoxygenation of anisole to arenes and inhibited the saturated hydrogenation on Cu/Al_(2)O_(3).With Mn doping increasing,the surface of Cu particles was modified with MnO_(x) along with enhanced generation of oxygen vacancies(Ov).The evolution of active sites structure led to a controllable adsorption geometry of anisole,which was beneficial for increasing arenes selectivity.As a result,the arenes selectivity obtained on 4Cu/8Mn4AlO_(x) was increased to be more than 6 folds of that value on 4Cu/4Al_(2)O_(3) over the synergistic sites between metal Cu and Ov generated on MnO_(x).

An efficient bifunctional Ni-Nb_(2)O_(5)nanocatalysts for the hydrodeoxygenation of anisole

The Ni-Nb_(2)O_(5)nanocatalysts have been prepared by the solgel method,and the catalytic hydrodeoxygenation(HDO)performance of anisole as model compound is studied.The results show that Nb exists as amorphous Nb_(2)O_(5)species,which can promote Ni dispersion.The addition of Nb_(2)O_(5)increases the acidity of the catalyst.However,when the content of niobium is high,there is an inactive Nb-Ni-O mixed phase.The size and morphology of Ni grains in catalysts are different due to the difference of Nb/Ni molar ratio.The Ni_(0.9)Nb_(0.1)sample has the largest surface area of 170.8 m^(2)·g^(-1)among the catalysts prepared in different Nb/Ni molar ratios,which is mainly composed of spherical nanoparticles and crack pores.The HDO of anisole follows the reaction route of the hydrogenation HYD route.The Ni_(0.9)Nb_(0.1)catalyst displayed a higher HDO performance for anisole than Ni catalyst.The selectivity to cyclohexane over the Ni_(0.9)Nb_(0.1)sample is about 10 times that of Ni catalyst at 220℃and 3 MPa H_(2).The selectivity of cyclohexane is increased with the increase of reaction temperature.The anisole is almost completely transformed into cyclohexane at 240℃,3 MPa H_(2)and 4 h.

Intrinsic kinetics of catalytic hydrogenation of 2-nitro-4-acetylamino anisole to 2-amino-4-acetylamino anisole over Raney nickel catalyst

The catalytic hydrogenation of 2-nitro-4-acetylamino anisole(NMA)is a less-polluting and efficient method to produce 2-amino-4-acetamino anisole(AMA).However,the kinetics of catalytic hydrogenation of NMA to AMA remains obscure.In this work,the kinetic models including power-law model and Langmuir-Hinshelwood-Hougen-Watson(LHHW)model of NMA hydrogenation to AMA catalyzed by Raney nickel catalyst were investigated.All experiments were carried out under the elimination of mass transfer resistance within the temperature range of 70–100°C and the hydrogen pressure of 0.8–1.5 MPa.The reaction was found to follow 0.52-order kinetics with respect to the NMA concentration and 1.10-order kinetics in terms of hydrogen pressure.Based on the LHHW model,the dual-site dissociation adsorption of hydrogen was analyzed to be the rate determining step.The research of intrinsic kinetics of NMA to AMA provides the guidance for the reactor design and inspires the catalyst modification.

GROWTH OF o-DICYANOVINYL ANISOLE(DIVA) CRYSTAL IN ORGANIC SOLVENTS

Crystal growth habits of O-Dicyanovinyl anisole (DIVA) in organic solvents are described

Acylation of Anisole Catalyzed by Hierarchical Porous Hβ Zeolite Modified with Cr

Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ray diffraction（XRD）, nitrogen adsorption-desorption~ scanning electron microscopy（SEM）, X-ray fluorescence（XRF）, NH3 temperature-programmed desorption and Fourier-transform infrared spectroscopy（FTIR）. The activities of acy- lation of anisole with acetic anhydride were also investigated. The results show that the Hp zeolite, which was treated with alkaline solution has microporous and mesoporous structures that could improve the diffusion performance of chemical reaction. The amount of acid was modulated with metal modification. The Hβ zeolite modified by 5%（mass fraction） metal chromium had the best catalytic performance. The conversion of acetic anhydride acylation was 93.01% under the optimal conditions, which was higher than that of other catalysts. The catalyst not only showed good activity, but also exhibited a stable performance in regeneration tests.

Electrochemical Oxidation Dearomatization of Anisol Derivatives toward Spiropyrrolidines and Spirolactones

Spiro compounds are widely prevalent in biological activities and natural products.However,developing new strategies for their efficient synthesis and derivatization remains a challenge.Outstanding progress has been made in the synthesis of spiro compounds through dearomatization of aromatic compounds,most of them are mediated by the hypervalent iodine reagents.Herein,we report a method of anodic oxidation spiroamination and spirolactonization of anisole derivatives with concomitant cathodic reduction of protons in the absence of hypervalent iodine reagents.A wide variety of spiropyrrolidines and spirolactones with diverse functional groups made useful scaffolds in this transformation,with yields up to 97%.Moreover,hectogram-scale synthesis could supply target product with 83% yield in a flow electrochemical cell using carbon paper as the anode and nickel plate as the cathode,demonstrating the potential application of this method.

NiCu-based catalysts for the low-temperature hydrodeoxygenation of anisole:Effect of the metal ratio on SiO_(2)andγ-Al_(2)O_(3)supports

The effects of the metal ratio of NiCu catalysts on the low-temperature hydrodeoxygenation(HDO)of anisole were assessed on a neutral SiO_(2) and an acidicγ-Al_(2)O_(3) support.The activity of SiO_(2)-supported catalysts increases with the Ni content in the NiCu phase,related to Ni’s hydrogenation capacity.In contrast,on aγ-Al_(2)O_(3) support,the activity decreases with the Ni content.Overall,Al_(2)O_(3)-supported catalysts,exhibiting a smaller NiCu alloy particle size,are more active than SiO_(2)-supported ones.In terms of selectivity,SiO_(2)-supported catalysts mainly hydrogenate anisole to methoxycyclohexane,while,particularly at higher conversions,γ-Al_(2)O_(3)-supported catalysts are able to further convert methoxycyclohexane to cyclohexane,demonstrating the importance of acid sites for low-temperature HDO.The Ni/Cu ratio also steers the selectivity,but not the catalyst stability.Deactivation phenomena are only support dependent:while on SiO_(2)-supported catalysts,active site sintering occurs,attributed to weak stabilization of metal particles by the support,acid catalyzed coking is the main cause of deactivation on theγ-Al_(2)O_(3)-supported catalysts.

Regulating electronic environment on alkali metal-doped Cu@NS-SiO_(2) for selective anisole hydrodeoxygenation

Lignin utilization is a potential approach for replacing fossil energy and releasing the environment pressure.Herein,we synthesized a series of novel Cu-based catalysts,Cu@NS-SiO_(2)(NS=nano sphere)and alkali metals(Na,K,Rb,and Cs)doped Cu@NS-SiO_(2),and applied them in hydrodeoxygenation reaction of anisole.High Cu dispersion was presented on all catalysts.The modification of alkali metals on Cu@NS-SiO_(2) significantly enhanced the electron density of Cu sites in the following order:Cs>Rb>K>Na,among which Cs decreased the Cu_(2)p_(3)/2 binding energy most(by 0.7 eV).Moreover,the modification did not substantially affect the geometric structure of Cu species.This regulable electronic environment of Cu sites was crucial for selective deoxygenation and inhibiting the hydrogenation of aromatic rings in anisole,and thus promoted the selectivity of benzene.Compared with Cu@NS-SiO_(2)(~59%),the highest benzene selectivity was obtained on Cs/10Cu@NS-SiO_(2) at~83%.

Design and optimization of a greener sinomenine hydrochloride preparation process considering variations among different batches of the medicinal herb

The current methods used to industrially produce sinomenine hydrochloride involve several issues,including high solvent toxicity,long process flow,and low atomic utilization efficiency,and the greenness scores of the processes are below 65 points.To solve these problems,a new process using anisole as the extractant was proposed.Anisole exhibits high selectivity for sinomenine and can be connected to the subsequent water-washing steps.After alkalization of the medicinal material,heating extraction,water washing,and acidification crystallization were carried out.The process was modeled and optimized.The design space was constructed.The recommended operating ranges for the critical process parameters were 3.0–4.0 h for alkalization time,60.0–80.0℃ for extraction temperature,2.0–3.0(volume ratio)for washing solution amount,and 2.0–2.4 mol·L^(-1) for hydrochloric acid concentration.The new process shows good robustness because different batches of medicinal materials did not greatly impact crystal purity or sinomenine transfer rate.The sinomenine transfer rate was about 20%higher than that of industrial processes.The greenness score increased to 90 points since the novel process proposed in this research solves the problems of long process flow,high solvent toxicity,and poor atomic economy,better aligning with the concept of green chemistry.

晶化时间对镁铝水滑石催化苯酚合成苯甲醚的影响

煤焦油中苯酚的高效定向转化制备精细化学品对于煤炭的高值化利用具有重要意义。采用共沉淀法经改变晶化时间制备出一系列镁铝水滑石样品,通过XRD、ICP-OES、TG、SEM、CO_(2)-TPD和NH_(3)-TPD等手段对水滑石及其焙烧产物进行表征,并考察了焙烧水滑石对苯酚与碳酸二甲酯经O-烷基化合成苯甲醚的反应的催化性能。结果表明,随晶化时间延长,镁铝水滑石的晶粒尺寸在a轴和c轴方向均逐渐增加,样品颗粒为片层结构的球形聚集体,颗粒尺寸逐渐增大,孔容和平均孔径逐渐增加,催化剂表面的弱碱量、弱酸量和强酸量均呈增加趋势而强碱量逐渐减少,强酸与强碱之比逐渐增大。在325℃、WHSV为2 h^(-1)下对物质的量比为1∶3的苯酚和碳酸二甲酯混合溶液在固定床中进行气相反应,所有催化剂对苯酚的转化率均在95%以上,苯甲醚的选择性随晶化时间的延长而逐渐提高,晶化时间为12 h所制备的镁铝水滑石样品作为催化剂时,苯酚的转化率为97.91%,苯甲醚的选择性为91.33%。

三氟化硼-苯甲醚络合物的管式裂解工艺研究

以三氟化硼-苯甲醚络合物为原料,采用管式裂解工艺,考察了裂解温度、停留时间以及预热温度对裂解反应的影响。采用气质联用仪定性分析了裂解后产物中的杂质,采用气相色谱外标法定量分析了各主要杂质的含量。通过研究获得了较优的管式裂解工艺参数,其中预热温度为40℃,裂解温度为185℃,停留时间为120 s,裂解率最高达到98.06%。

顶空固相微萃取-气相色谱质谱法测定水体中的苯甲醚

建立了顶空固相微萃取-气相色谱质谱法定性定量检测水中苯甲醚的分析方法。对影响检测结果的因素如萃取头的选择、萃取时间等进行了优化。经过条件优化,方法在1~1000μg/L范围内线性良好,线性相关系数>0.999,实际水样加标质量浓度分别为10,60,300μg/L时,加标回收率为85%~120%,相对标准偏差(RSD)为3.95%~6.72%。全扫描模式下,苯甲醚的检出限为0.3μg/L。实验结果表明,该方法快速、简便、灵敏度高,方法精密度和准确度均能满足水中微量及痕量苯甲醚检测的要求。

4-甲基苯甲醚催化氧化产物的液相色谱分析

4-甲基苯甲醚的催化氧化产物主要有4-甲氧基苯甲醇、4-甲氧基苯甲醛、4-甲氧基苯甲酸、4-甲氧基苄基乙酸酯等。本文采用高效液相色谱法,通过C_(18)反相色谱柱和二极管阵列检测器,确定上述各催化氧化产物同时存在时,紫外检测波长为198nm时各物质的吸收情况最优。对流动相组成、流动相比例、流速、柱温等色谱条件进行筛选。将体积比为55∶45的乙腈-0.1%三氟乙酸水溶液的混合溶液作为流动相,流速为0.8mL·min^(-1)进行等梯度洗脱,检测柱温为20℃时,分离效果最佳。在此条件下对4-甲基苯甲醚的催化氧化产物进行跟踪检测,结果表明,催化氧化产物在0.01~0.2 mg·mL^(-1)范围内呈良好的线性关系,相关系数为0.99。该方法简单便捷,灵敏度高,重复性好,专属性高,结果稳定,是分析4-甲基苯甲醚催化氧化产物的理想方法。