碳酸钾催化苯酚在超临界CO2中合成水杨酸的实验研究

在超临界CO2中以K2CO3为催化剂,由苯酚一步直接合成了水杨酸.改进了传统的有机酚酸(Kolbe-Schmitt 反应)的两步法合成工艺.在CO2压力4～14 MPa、温度160～220℃,考察温度、压力、反应时间、催化剂用量等条件对水杨酸收率的影响.水杨酸最高得率接近54%,产物的选择性在99%以上,副产物有极少量...     

邻氯苯胺碱解制备邻甲酚工艺研究

以邻氯甲苯为原料加压碱解制备邻甲酚,具有合成路线短、操作简单、产品纯度高、催化剂可回收套用等特点。对该工艺条件进行优化,优化条件及结果如下:以CuSO4.5H2O为催化剂、反应温度260℃、反应时间10 h、反应压力4 MPa、反应配比为1∶2.6时,产物收率达到92.1%。     

Pt/C催化剂催化邻硝基苯甲醚加氢制备邻氨基苯甲醚

以邻硝基苯甲醚为原料,采用Pt/C催化剂,通过液相催化加氢工艺合成邻氨基苯甲醚,研究不同反应条件对其转化率和选择性的影响,确定最佳工艺条件为,无水乙醇作溶剂、反应温度80℃、反应压力2 MPa、Pt/C催化剂用量0.01 g和反应时间2 h。相比传统硫化钠法和铁粉盐酸法等,催化加氢还原工艺可有效解决废水污染问题,提高产品收率和品质,降低生产成本,同时更易实现自动化生产,属于绿色新型工艺,具有良好的工业化前景。     

苯酚甲醇气相催化甲基化合成邻甲酚和2,6-二甲酚中间试验研究

本文叙述了苯酚与甲醇气相催化甲基化合成邻甲酚和2,6-二甲酚催化剂V2O5-Fe2O3的中试放大研究,在催化剂负荷的90g-PhOH/kg-cat·h,原料配比PhOH：MeOH：H2O=1：4：3（mol）,催化剂连续运转2000h,苯酚单程转化率达69．4％,邻甲酚选择性75．1％,邻甲酚单程摩尔收率达51．8％。     

医药中间体邻乙酰氧基苯甲酰氯合成方法改进

在超声波辐射下,以邻乙酰水杨酸、氯化亚砜为反应原料,无水吡啶为溶剂合成制得邻乙酰水杨酰氯。并通过正交设计确定了最佳反应条件:反应温度为65℃、超声波功率为100W、反应时间为2h,收率可达83.2%。     

苯酚气相甲基化催化剂单管放大及再生试验研究

本文叙述了苯酚与甲醇气相催化甲基化合成邻甲酚和2,6-二甲酚催化剂V₂0₅-Fe₂O₃的单管放大研究,选取反应管内径Φ32mm,装填催化剂2kg,装填高度2500mm,在催化剂负荷90g-Ph/kg-cat·h,原料配比PhOH∶MeOH∶H₂O＝1∶₄∶3(mol)条件下,催化剂连续运转2400小时,催化剂共进行了4次再生,苯酚单程转化率为62.21%,邻甲酚选择性80.47%,邻甲酚单程摩尔收率50.06%。     

Cu/Ni超细混合催化糠醛加氢合成2-甲基四氢呋喃的研究

采用溶胶-凝胶法制备了Cu/Ni超细混合催化剂,并用于糠醛液相加氢制2-甲基四氢呋喃反应。考察了Cu/Ni摩尔比,Na2CO3溶液浓度等催化剂制备条件,以及合成反应中反应压力、反应时间、反应温度等反应条件对糠醛转化率和2-甲基四氢呋喃选择性的影响。结果表明：催化剂制备条件为Cu/Ni摩尔比为5/5,Na2CO3溶液浓度为1.0 mol/l;合成反应条件为反应压力8 MPa,反应时间3.5 h,反应温度180 ℃;产品经气相色谱检测分析,糠醛的转化率为100%,2-甲基四氢呋喃的选择性为64.52%。     

β-邻苯二甲酰亚胺基丙醛缩乙二醇的新合成方法

以四丁基溴化铵为相转移催化剂,无水K2CO3为碱性催化剂,邻苯二甲酰亚胺与β溴代丙醛缩乙二醇经Gabriel反应合成了标题化合物。在邻苯二甲酰亚胺与β溴代乙二醇缩丙醛的物质的量比为1.1∶1,反应温度100～103℃,反应时间3.5h,在此条件下,收率达95.9%。     

CO加氢合成低碳醇用CuCo/SiO2催化剂的反应性能研究

采用共浸渍法制备了CuCo/SiO₂双金属催化剂,以CO加氢合成低碳醇为模型反应考察了不同反应温度、压力和空速下催化剂的反应性能,并采用X射线（XRD）、热重分析(TG)和程序升温还原(TPR)技术对催化剂进行了表征。结果表明,（533～563） K,随反应温度升高,CO 转化率从14.9%增加到40.4%,醇类的时空收率呈现先增大再减小的趋势, 553 K取得最优值;升高反应压力能显著提高醇类的选择性;（1 200 ~4 800） h^-1,随空速增加,CO 加氢活性降低,醇类产物的选择性显著增加, 使时空收率提高。〖JP2〗XRD结果表明,反应前催化剂主要成分为CuO、Co₃O₄和CuCo尖晶石物相,反应后则为Cu⁰和Co²⁺。TG和TPR结果表明,前驱体的适宜焙烧温度为623 K,催化剂的原位还原温度为593 K。     

邻苯二甲醇合成新工艺研究

以邻二氯苄为原料,在乙醇/水体系中经过Na_2CO_3水解,合成了邻苯二甲醇。考察了水醇体积比、反应原料摩尔比、反应时间以及反应温度对产品收率的影响,确定了最佳反应条件。通过红外光谱对产物进行了结构表征,利用高效液相色谱测定了产品的纯度。结果表明:在水醇体积比5∶1的体系中,在反应时间8 h、反应温度90℃、邻二氯苄与无水碳酸钠摩尔比为1∶1.3的最佳反应条件下,合成的邻苯二甲醇收率可达86%,纯度(w)达98%。该工艺操作简单、反应条件温和、成本低,有利于工业化生产。     

金属醋酸盐复配催化剂催化超临界CO2一步法合成碳酸二甲酯

由CO2合成碳酸二甲酯(DMC)是CO2资源化的重要途径之一。超临界CO2因具有独特的溶解和传递性能,在合成反应中可既作反应物,又作反应溶剂。本实验以超临界CO2、环氧丙烷和甲醇作为反应物,选用金属醋酸盐与K2CO3、KI复合催化一步合成DMC。在温度130~170℃、CO2压力2~14 MPa条件下,考察了催化剂用量、物料配比、温度、压力、反应时间等条件对DMC产率的影响,产物采用气相色谱以内标法进行定量分析。结果表明,当醋酸锌复合催化剂配比为K2CO3:KI:Zn(CH3COO)2=1:1:2时,在合适的反应条件下(催化剂用量4%,物料配比8:1,160℃、7.4MPa,反应4 h),环氧丙烷转化率可达95%,DMC产率可达54.3%。     

活性炭固载对甲苯磺酸催化合成水杨酸乙酯

实验以活性炭负载对甲苯磺酸为催化剂,水杨酸和无水乙醇为原料合成水杨酸乙酯。考察了反应时间、醇酸摩尔比、催化剂的用量对水杨酸乙酯收率的影响。结果表明最佳工艺条件为：在回流温度90．-95~CT,反应时间为4h,醇酸摩尔比为4,催化剂的用量为反应物总质量的8％,水杨酸乙酯的收率可达34,9％,且催化剂可重复利用。     

超(近)临界流体中甲苯氧化成苯甲醛

分别研究了在超临界二氧化碳和近临界水中以过氧化氢为氧源、无催化剂条件下,甲苯氧化成苯甲醛的工艺优化及氧化反应动力学.研究结果表明,在超临界二氧化碳中的最佳工艺条件为：P=25 MPa,T=180 ℃,t=4 h,η=2.5.氧化反应呈现零级反应特征,反应活化能E_a=50.9 kJ•mol^-1.在近临界水中的最佳工艺条件为：P>P₀,T=350 ℃,t=1 h,η=3.5.氧化反应由两个一级反应组成连串反应,反应活化能分别为E_a1=89 kJ•mol^-1,E_a2=76 kJ•mol^-1.     

Extraction of Fatty Acids from <Emphasis Type="Italic">Boletus edulis</Emphasis> by Subcritical and Supercritical Carbon Dioxide

Mushrooms contain many valuable compounds such as fatty acids, carbohydrates, lycopene, lovastatin, trace elements etc. As they are currently valued for biologically active substances, and as high pressure carbon dioxide fluid extraction has been documented as an effective method for preparing bioactive products from plant materials, subcritical and supercritical carbon dioxide extraction of Boletus edulis mushroom was performed. In the extracts obtained, the fatty acids were determined. Response surface methodology (RSM) was applied to investigate the effect of pressure and extraction time on the extraction yield. The analysis of variance showed that pressure and extraction time had a significant effect on the extraction yield in both investigated process. The interaction between pressure and extraction time had a significant effect only in supercritical extraction process of B. edulis. Higher extraction yields have been obtained by subcritical carbon dioxide, and higher linoleic acid content has been determined in extracts obtained by supercritical carbon dioxide.     

活性炭固载酸性催化剂合成水杨酸异丙酯

以水杨酸和异丙醇为原料,采用颗粒状活性炭固载对甲苯磺酸作催化剂合成水杨酸异丙酯,考察影响反应因素,结果表明,酯化反应最佳条件为:n(水杨酸)∶n(异丙醇)=1∶3.0,催化剂用量1.5 g,为反应物总质量的4.6%,反应时间3.0 h,带水剂甲苯用量8 mL,此条件下,水杨酸异丙酯收率可达94.45%。     

超临界二氧化碳中丙烯酸乙酯/3-氯丙烯接枝天然橡胶的合成与表征

采用超临界二氧化碳溶胀聚合法,以丙烯酸乙酯（EA）/3-氯丙烯（AC）为单体对天然橡胶进行了接枝改性,合成了接枝共聚物NR-g-(EA/AC)。考察了压力和引发剂用量对接枝聚合反应的影响;对NR-g-( EA/AC)进行了红外光谱、力学性能、耐溶剂性、耐燃性、硬度的测试及接枝效率和接枝率的计算,并与溶液聚合法所得NR-g-( EA/AC)的性能进行了比较。结果发现,在接枝橡胶中成功的引入了—C=O和—Cl基团;接枝橡胶的弹性模量、拉伸强度、硬度、耐燃性和耐溶剂性较天然橡胶的有了显著提高。使用溶液法和超临界二氧化碳溶胀聚合法改性天然胶乳都获得了较高的转化率和接枝率,所得产品的机械力学性能相近,但溶液法所得产品的耐溶剂性能优于后一种方法。由于超临界二氧化碳的绿色溶剂性质,超临界二氧化碳溶胀聚合法有望取代溶液聚合法而发展成一种绿色的接枝改性天然橡胶方法。     

Extraction of pomegranate seed oil using subcritical propane and supercritical carbon dioxide

Extraction of oil from pomegranate seeds as a waste product of the juice industry using supercritical carbon dioxide and subcritical propane was studied in this work. The influence of the main operating conditions of extraction, namely, the temperature and pressure of extraction on the oil extraction yield and the correspondent fatty acid profile were analyzed and reported here. Soxhlet extraction with n-hexane was done for comparison with supercritical extraction resulting in a maximum yield of oil of 22.31 wt %. Supercritical carbon dioxide and subcritical propane extracted up to 58.53% (corresponding to maximum yield of 13.06 wt %) and 76.73% (corresponding to maximum yield of 17.12 wt %) of the total amount of pomegranate seed oil as measured using Soxhlet extraction, respectively. Results indicated that the subcritical propane is a suitable and selective solvent for the extraction of the pomegranate seed oil in function of smaller times and pressures employed compared to carbon dioxide extraction. The fatty acid composition of the extracted oil showed the presence of fatty acids of C₁₆, C₁₈, C₂₀, C₂₂, and C₂₄ carbon chains. Punicic (C_18.3) was the major fatty acids and comprise up to 70% of the total fatty acid content of the extracted oil among all samples. Finally, Lack??s plug flow model as developed by Sovova was applied to both extraction systems and a good agreement with the experimental results was obtained.     

尿素催化合成乙酰水杨酸

以水杨酸和乙酸酐为原料,采用尿素作催化剂合成乙酰水杨酸。考察了温度、尿素用量、n(水杨酸)∶n(乙酸酐)和时间对反应的影响。正交试验结果表明,较适宜的反应条件为:n(水杨酸)∶n(乙酸酐)=1∶3,尿素用量为水杨酸质量的5%,反应温度85℃,反应时间60 min,此条件下,乙酰水杨酸收率达94.06%。     

Probing Active Sites During Palladium-Catalyzed Alcohol Oxidation in “Supercritical” Carbon Dioxide

Structural information has been gained during aerobic benzyl alcohol oxidation in “supercritical” carbon dioxide at 150 bar on alumina-supported palladium by X-ray absorption spectroscopy while monitoring simultaneously the performance of the catalyst. The reduction of the catalyst by benzyl alcohol could be monitored by the analysis of the near-edge region of the Pd K-edge. The palladium constituent was mainly in metallic state under operating conditions. Partial reoxidation was observed when only oxygen in “supercritical” carbon dioxide in the absence of alcohol was fed. The catalytic activity of the PdO_x/Al₂O₃ catalyst during benzyl alcohol oxidation was comparable to that in a conventional continuous fixed-bed reactor and depended on the oxygen concentration in the feed. The rate of alcohol conversion went through a maximum when the oxygen concentration was increased. At maximum rate, part of the palladium was in the oxidized state. Upon further increase of the oxygen concentration, the activity decreased because of the formation of surface palladium oxide. The reaction rate in “supercritical” carbon dioxide was strikingly higher than that observed for the corresponding liquid-phase oxidation.     

含乙醇废水的超临界水氧化反应动力学及反应机理

研究了等温平推流反应器中乙醇的超临界水氧化反应（SCWO）,反应温度475～550 ℃、压力22～30 MPa、停留时间0.6～63.7 s、氧气与乙醇摩尔浓度比4.56～9.09.一氧化碳和二氧化碳分别是反应中间产物和最终产物.随停留时间增大、温度升高,乙醇去除率增大,压力和氧气浓度变化对过程无显著影响.以幂指数方程描述乙醇SCWO动力学,乙醇和氧气的反应级数分别为1和0,计算值和实验值相差基本在10%以内.超临界条件下分别以过氧化氢和氧气为氧化剂时乙醇的氧化反应无明显差别,亚临界条件下过氧化氢氧化速率大于氧气.基于对此现象的分析,作者推测：无论以过氧化氢或氧气作为氧化剂,在超临界水中,它们之间可以通过一系列自由基反应迅速达到平衡,且各物种的平衡分布与初始分布无关,体系的主要氧化过程在平衡分布下进行.