Synthesis of Methyl Glycolate by Hydrogenation of Dimethyl Oxalate over Cu-Ag/SiO_2 Catalyst

Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.

负载型ZnCl_(2)/AC催化剂用于乙二醇氢氯化反应的研究

采用湿浸渍法制备了ZnCl_(2)/AC(活性炭)催化剂并用于乙二醇氢氯化反应合成2-氯乙醇,通过XRD、FT-IR、Py-IR和N_(2)等温吸附-脱附等手段对催化剂进行表征,考察了ZnCl_(2)负载量对AC的物化性质和催化活性的影响。结果表明,负载ZnCl_(2)后,AC上的Lewis酸位点数量显著增加,催化活性得到显著增强。在温度为220℃、LHSV为1 h^(-1)、n(HCl)/n(EG)为2∶1时,10%ZnCl_(2)/AC催化剂表现出最佳催化性能,乙二醇转化率和2-氯乙醇选择性分别为88.26%和93.57%。

包封骨形态发生蛋白2的不同相对分子质量聚乳酸-聚乙醇酸共聚物微囊促进成骨效果的研究

目的 探索不同相对分子质量聚乳酸-聚乙醇酸共聚物(PLGA)微囊包封骨形态发生蛋白2 (BMP-2)对成骨细胞骨形成能力的影响。方法 用双通道微量注射泵制备包封BMP-2的2种相对分子质量(12 000和30 000)的PLGA微囊。用光学显微镜及扫描电子显微镜(SEM)观察微囊形态结构;磷酸盐缓冲溶液浸泡法表征微囊缓释性能;细胞Calcein-AM/PI染色及CCK-8法检测微囊细胞相容性;Transwell迁移实验检测包封BMP-2的微囊作用48 h对MC3T3-E1细胞的趋化作用;碱性磷酸酶活力测定、茜素红染色法检测微囊作用MC3T3-E1细胞后对细胞骨形成能力的影响。结果 2种相对分子质量的微囊均表面光滑,具有良好的细胞相容性。相对分子质量12 000的微囊的趋化作用最佳。相对分子质量30 000的微囊较相对分子质量12 000的微囊缓释时间长,且初始爆发量减少了约25%。成骨诱导14、21 d后,相对分子质量30 000的微囊形成的钙沉积结节较相对分子质量12 000的微囊多。结论 本研究通过调控PLGA的相对分子质量控制BMP-2的释放,发现相对分子质量30 000的微囊能够更好地诱导MC3T3-E1细胞的长期骨形成能力。

一次性使用输液器产品中2-氯乙醇和乙二醇残留量的测定方法研究

目的:建立有效测定经环氧乙烷(ethylene oxide,EO)灭菌后一次性使用输液器产品中2-氯乙醇(ethylene chlorohydrin,ECH)和乙二醇(ethylene glycol,EG)残留量的方法。方法:选用8890B气相色谱仪,采用液体进样方式,选择DB-WAX色谱柱,以乙醇作为浸提介质,按照一次性使用输液器质量与浸提介质体积比例为0.4 g/mL进行浸提,在37℃浸提10 h后对一次性使用输液器产品中的ECH和EG进行定量测定。结果:该测定方法专属性较强,ECH与EG均在1.25~100.00μg/mL范围内线性关系良好。ECH和EG的检出限分别为0.31和0.11μg/mL。ECH检测精密度的相对标准偏差为0.24%~2.03%,EG检测精密度的相对标准偏差为0.16%~0.87%。ECH检测的平均回收率为95.02%~100.58%,EG检测的平均回收率为99.15%~99.98%。结论:建立的ECH和EG残留量测定方法操作简单、专属性优良、检测准确、重现性好,可满足经EO灭菌的一次性使用输液器产品中ECH和EG残留量的检测需求。

煤基化学品中CO_(2)综合利用的研究进展

全球每年CO_(2)排放量达到百亿吨左右,除了造成资源浪费、生产成本增加以外,无形之中也给环境保护带来巨大的压力,尤其是在双碳目标提出后,如何提高CO_(2)的综合利用成为国内外学者研究的重中之重。分析总结了煤制甲烷、烯烃、甲醇等传统工艺中,CO_(2)作为补充碳源对传统工艺的影响。对比后发现,补入系统中的CO_(2)不仅提高了碳资源的利用率,同时一定程度上减少了成产成本的投入,即在“节能减排”、“增效创收”等方面发挥着显著作用。

聚乙二醇洛塞那肽与利拉鲁肽治疗肥胖2型糖尿病疗效对比

目的通过比较聚乙二醇洛塞那肽与利拉鲁肽治疗肥胖2型糖尿病的疗效,为临床治疗该类疾病选择更高效的用药方案。方法选取东南大学医学院附属南京同仁医院2022年1月至2023年10月予以相应治疗的肥胖2型糖尿病患者共136例作为此次试验对象,按照随机数字表法分成68例A组(聚乙二醇洛塞那肽治疗)与68例B组(利拉鲁肽治疗)。比较治疗前后两组肥胖相关指标、治疗前后两组血脂相关指标、治疗前后两组血糖指标以及治疗后不良反应发生率。结果治疗后两组体质量、腰臀比、体质量指数(BMI)和腰围均下降,B组体质量和BMI[分别为(80.31±7.62)kg和(24.13±1.82)kg·m^(-2)]低于A组体质量[分别为(83.65±7.93)kg和BMI(25.34±1.84)kg·m^(-2)](体质量:t=2.504,P=0.014;BMI:t=3.855,P<0.05);治疗后两组甘油三酯(TG)、血清总胆固醇(TC)和低密度脂蛋白(LDL)均下降,高密度脂蛋白胆固醇(HDL-C)上升(均P<0.05);治疗后两组餐后2 h血糖(2 h FBG)、空腹血糖(FBG)、糖化血红蛋白(HbAlc)、胰岛素抵抗指数(HOMA-IR)水平均下降,空腹血糖胰岛素(FINS)、β细胞功能指数(HOMA-β)水平均上升,A组2 h FBG、FBG[分别为(7.86±1.12)mmol·L^(-1)、(6.18±0.71)mmol·L^(-1)]低于B组[分别为2 h FBG(8.72±1.34)mmol·L^(-1)和FBG(7.02±0.62)mmol·L^(-1)](2 h FBG:t=4.061,P<0.05;FBG:t=7.349,P<0.05),A组HOMA-β[(74.62±3.78)%]高于B组[(62.79±3.56)%](t=18.937,P<0.05);两组不良反应发生率比较差异无统计学意义(20.59%vs 25.00%,χ^(2)=0.376,P=0.540)。结论对于肥胖2型糖尿病患者,聚乙二醇洛塞那肽与利拉鲁肽均能有效减轻体质量、调节血脂、降低血糖水平以及增强胰岛β细胞的功能,且安全性相似。然而,在降低体质量方面,利拉鲁肽的效果更为显著,而聚乙二醇洛塞那肽在改善胰岛β细胞功能和降低血糖方面则表现更为出色。

PEG-2000添加量对Pr_(x)Zr_(1-x)O_(2-δ)催化氧化NO活性的影响

采用溶胶-凝胶法制备了Pr_(x)Zr_(1-x)O_(2-δ)催化剂,并用于NO催化氧化。以聚乙二醇-2000(PEG-2000)为模板剂对催化剂进行改性,研究了不同模板剂添加质量分数对NO催化氧化活性的影响。结果表明,催化剂活性随PEG-2000添加质量分数的增加而降低;在300℃、PEG-2000添加质量分数为2%时,Pr_(x)Zr_(1-x)O_(2-δ)的催化活性最高,NO转化率达到了94.81%。利用XRD、SEM、N2吸附-脱附、XPS及FT-IR对催化剂进行表征,结果表明,模板剂添加质量分数的变化不会改变催化剂Pr_(2)Zr_(2)O_(7)晶型;催化剂为介孔结构,质量分数为2%时的比表面积和孔容最大,有利于催化氧化NO。此外,模板剂质量分数的增加会增强催化剂的亲水性。

聚乙二醇洛塞那肽与二甲双胍联合治疗对初诊肥胖2型糖尿病患者糖脂代谢的影响

目的研讨聚乙二醇洛塞那肽与二甲双胍联合治疗对初诊肥胖2型糖尿病患者糖脂代谢的影响。方法选取初诊肥胖2型糖尿病患者80例,按照随机数表法划分为对照组和观察组,每组40例。对照组给予二甲双胍单药降糖,观察组基于对照组用药条件施加聚乙二醇洛塞那肽治疗。对比两组用药前后的血糖水平、血脂水平、机体应激反应指标水平以及用药安全性。结果用药后,观察组空腹血糖、餐后2 h血糖、糖化血红蛋白分别为(5.87±0.85)mmol/L、(8.62±1.38)mmol/L、(6.12±0.94)%,相比对照组的(7.02±1.14)mmol/L、(9.42±1.55)mmol/L、(7.23±1.21)%均更低,差异有统计学意义(P<0.05)。观察组高密度脂蛋白胆固醇为(1.13±0.17)mmol/L高于对照组的(1.05±0.15)mmol/L,总胆固醇、甘油三酯、低密度脂蛋白胆固醇分别为(4.05±0.71)、(1.87±0.56)、(2.21±0.65)mmol/L,均低于对照组的(4.69±0.83)、(2.23±0.68)、(2.69±0.71)mmol/L,差异有统计学意义(P<0.05)。观察组用药后血清超敏C反应蛋白、白细胞介素-6以及丙二醛分别为(6.24±0.65)mg/L、(5.79±0.71)ng/L、(4.70±0.89)μmol/L,相比对照组的(7.88±0.87)mg/L、(6.32±1.01)ng/L、(5.41±1.05)μmol/L均更低,差异有统计学意义(P<0.05)。两组发生药物不良反应的患者总占比对比,差异不具统计学意义(P>0.05)。结论聚乙二醇洛塞那肽与二甲双胍联合用于初诊肥胖2型糖尿病患者的治疗,能够更好地调节患者糖脂代谢状况,减轻机体应激反应,并保障用药安全。

Cu_2[ethyleneglycolbis(2-aminoethy)tetraacetate·2H_2O]·2H_2O:双核铜配合物的合成和晶体结构

乙二醇双(2-氨乙基醚)四乙酸(ethylene glycol bis(2-amino ethy)tetraacetate:EGTA)和氯化铜采用溶液蒸发方法在甲醇和水的混合溶液中成功合成双核铜配合物Cu2[EGTA.2H2O].2H2O。该晶体的结构数据是在单晶衍射仪进行收集的。通过晶体结构分析,该晶体属单斜晶系,空间群为C2/c,晶胞参数如下:a=21.013(4),b=7.5503(1),c=13.577(2),β=90.877(2)°,V=2153.8(6)3。在化合物中,铜离子分别与配体的三个氧原子和一个氮原子以及一个水分子成键,采取五配位四面体构型,铜离子空间构型是畸变的四方锥。另外,游离的水分子与配体的氧原子形成氢键而构筑成超分子。

Effect of copper loading on texture,structure and catalytic performance of Cu/SiO_2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

Cu/SiO2 catalysts prepared by a convenient and efficient method using the urea hydrolysis deposition-precipitation （UHDP） technique have been proposed focusing on the effect of copper loading.The texture,structure and composition are systematically characterized by ICP,FTIR,N 2-physisorption,N2O chemisorption,TPR,XRD and XPS.The formation of copper phyllosilicate is observed in Cu/SiO2 catalyst by adopting UHDP method,and the amount of copper phyllosilicate is related to copper loading.It is found the structure properties and catalytic performance is profoundly affected by the amount of copper phyllosilicate.The excellent catalytic activity is attributed to the synergetic effect between Cu0 and Cu ＋.DMO conversion and EG selectivity are determined by the amount of Cu0 and Cu＋,respectively.The proper copper loading （30 wt%） provides with the highest ratio of Cu ＋ /Cu0,giving rise to the highest EG yield of 95% under the reaction conditions of p=2.0 MPa,T=473 K,H2/DMO=80 and LHSV=1.0h-1.

Synthesis of 2-methylpyrazine from cyclocondensation of ethylene diamine and propylene glycol over promoted copper catalyst

The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.

Efficient one-pot hydrogenolysis of biomass-derived xylitol into ethylene glycol and 1,2-propylene glycol over Cu–Ni–ZrO_2 catalyst without solid bases

The directly selective hydrogenolysis of xylitol to ethylene glycol(EG) and 1,2-propylene glycol(1,2-PDO)was performed on Cu–Ni–ZrO_2 catalysts prepared by a co-precipitation method. Upon optimizing the reaction conditions(518 K, 4.0 MPaH_2 and 3 h), 97.0% conversion of xylitol and 63.1% yield of glycols were obtained in water without extra inorganic base. The catalyst still remained stable activity after six cycles and above 80% total selectivity of glycols was obtained when using 20.0% xylitol concentration. XRD, TEM and ICP results indicated that Cu–Ni–ZrO_2 catalysts possess favorable stability. Cu and Ni are beneficial to the cleavage of C–O and C–H bond, respectively. To reduce the hydrogen consumption, isopropanol was added as in-situ hydrogen source and 96.4% conversion of xylitol with 43.6% yield of glycols were realized.

An efficient and stable Cu/SiO_2 catalyst for the syntheses of ethylene glycol and methanol via chemoselective hydrogenation of ethylene carbonate

The efficient synthesis of methanol and ethylene glycol via the chemoselective hydrogenation of ethylene carbonate（EC） is important for the sustainable utilization of CO_2 to produce commodity chemicals and fuels. In this work, a series of β-cyclodextrin-modified Cu/SiO_2 catalysts were prepared by ammonia evaporation method for the selective hydrogenation of EC to co-produce methanol and ethylene glycol. The structure and physicochemical properties of the catalysts were characterized in detail by N_2 physisorption, XRD, N_2O titration, H_2-TPR, TEM, and XPS/XAES. Compared with the unmodified 25 Cu/SiO_2 catalyst, the involvement of β-cyclodextrin in 5β-25 Cu/SiO_2 could remarkably increase the catalytic activity—excellent activity of 1178 mgEC g_（cat）^（–1） h^（–1） with 98.8%ethylene glycol selectivity, and 71.6% methanol selectivity could be achieved at 453 K. The remarkably improved recyclability was primarily attributed to the remaining proportion of Cu~＋/（Cu^0＋Cu~＋）. Furthermore, the DFT calculation results demonstrated that metallic Cu^0 dissociated adsorbed H_2, while Cu~＋ activated the carbonyl group of EC and stabilized the intermediates. This study is a facile and efficient method to prepare highly dispersed Cu catalysts—this is also an effective and stable heterogeneous catalyst system for the sustainable synthesis of ethylene glycol and methanol via indirect chemical utilization of CO_2.

Catalytic Performance and Texture of TEOS Based Cu/SiO_2 Catalysts for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

Highly active and selective Cu/SiO2 catalysts for hydrogenation of dimethyl oxalate（DMO） to ethylene glycol（EG） were successfully prepared by means of a convenient one-pot synthetic method with tetraethoxysi lane（TEOS） as the source of silica. XRD, H2-TPR, SEM, TEM, XRF and N2 physisorption measurements were performed to characterize the texture and structure of Cu/SiO2 catalysts with different copper loadings. The active components were highly dispersed on SiO2 supports. Furthermore, the coexistence of Cu0 and Cu＋ contributed a lot to the excellent performance of Cu-TEOS catalysts. The DMO conversion reached 100% and the EG selectivity reached 95% at 498 K and 2 MPa with a high liquid hourly space velocity over the 27-Cu-TEOS catalyst with an actual cop per loading of 19.0%（mass fraction）.

Zn–Ca–Al mixed oxide as efficient catalyst for synthesis of propylene carbonate from urea and 1,2-propylene glycol

A series of Zn–Ca–Al oxides with different CaO and ZnO contents have been prepared and evaluated in the synthesis of propylene carbonate(PC) from 1,2-propylene glycol(PG) and urea in a batch reactor. The effect of catalyst composition, basicity and reaction process parameters such as temperature, catalyst dose, molar ratio of PG to urea, purge gas flow and reaction time has been studied to find suitable reaction conditions for the PC synthesis. The PC selectivity and yield under the desired conditions could reach 98.4% and 90.8%, respectively. The best performing catalyst also exhibited a good reusability without appreciable loss in the PC selectivity and yield after five consecutive reaction runs. In addition, a stepwise reaction pathway involving a 2-hydroxypropyl carbamate intermediate was proposed for the urea alcoholysis to PC in the presence of Zn–Ca–Al catalysts, according to the time dependences of reaction intermediates and products.

In situ IR study of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO_2 catalyst

The mechanism of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst was investigated by in situ Fourier transform infrared （FTIR） spectroscopy. It was found that dimethyl oxalate and methyl glycolate proceeded via dissociative adsorption on Cu/SiO2 catalyst, and four main intermediates, CH3OC（O）（O）C-M （1655 cm-1）, M-C（O）（O）C-M （1618 cm-1）, HOCH2（O）C--M （1682 cm-1） and CH3O-M （2924-2926 cm-1）, were identified during the reaction. It was concluded that dimethyl oxalate hydrogenation to ethylene glycol mainly proceeded along the route： dimethyl oxalate ／rightarrow CH3OC（O）（O）C-M → methyl glycolate →HOCH2（O）C-M → ethylene glycol. Finally a schematic reaction network was proposed.

Ethylene glycol purification by melt crystallization:Removal of 2-methoxyethanol impurity

The coal(syngas)-to-ethylene glycol(CTEG),is contaminated with the naughty impurity 2-Methoxyethanol(ME)generated during the hydrogenation stage,which affect the quality of EG for fiber-grade polyester production.Distillation,is the employed separation process in industrial,which makes production complicated because of the heat sensitivity of the impurities system.Melt crystallization has been regarded as an effective technology to obtain high-purity organic compounds based on the melting points difference,which could avoid the problems by heating.In this work,we have explored the feasibility of the static melt crystallization on the separation of EG/ME in a jacketed crystallization tube.The experimental parameters were investigated,which covers crystallization and sweating stage in each step.The results showed that the purity of EG could reach≥99.8%from the binary system studied via the quaternary separation process.

Revealing the roles of components in glucose selective hydrogenation into 1,2-propanediol and ethylene glycol over Ni-MnO_x-ZnO catalysts

MnOx-promoted Ni-based catalyst supported by ZnO was developed to selectively hydrogenate glucose into polyols in water at 523 K with a yield of 64.9%. Using glucose, sorbitol, glycerol and LA as the rawmaterials, the roles of nickel, ZnO and MnOx were investigated. The results show that nickel provided a new pathway of glucose to sorbitol and played an important role in the hydrogenation of C3 intermediates to 1,2-propanediol(1,2-PDO). The high yield of 1, 2-PDO was attributed to effective C–C bond cleavage performance of ZnO support promoted by MnOx. ZnO and MnOx contribute to the conversion of glycerol to lactic acid(LA) and LA to 1, 2-PDO, respectively. A concise pathway for hydrogenation of glucose over Ni-based catalyst was proposed.

Solubilities of CO2 in some glycol ethers under high pressure by experimental determination and correlation

The binary vapor–liquid equilibrium data of CO_2 in diethylene glycol(monomethyl,monoethyl,monobutyl,dimethyl,diethyl,dibutyl)ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constant-volume method.It was found by contrast that the ether group in solvents can promote the CO_2 absorption,but the hydroxyl group will inhibit the CO_2 absorption.Furthermore,the solubilities of CO_2 showed an upward trend with the increasing molecular lengths of absorbents.The experimental data were also correlated with a modified Patel–Teja equation of state(PT EOS)combined with the traditional van der Waals one-fluid mixing rules and the results showed a satisfactory agreement between the model and the experimental data.

水-乙二醇基γ-Al_(2)O_(3)纳米流体的制备及其性能研究

以水-乙二醇为基液,通过两步法制备了质量分数为0.1%的γ-Al_(2)O_(3)纳米流体。考察了乙二醇体积分数、分散剂质量分数及种类、超声时间对纳米流体稳定性的影响。结果表明,乙二醇体积分数为35%时更适用于水-乙二醇基纳米流体的制备;质量分数为0.2%的阿拉伯树胶(GA)可有效提高γ-Al_(2)O_(3)纳米颗粒在水-乙二醇基液中的分散稳定性;超声30 min即可改善纳米流体的稳定性。最后评价了纳米流体的热物性,当与基液水浴加热到60℃时,水-乙二醇基γ-Al_(2)O_(3)纳米流体的导热性能提升幅度最大,为基液的1.35倍;在20~60℃加热过程中,Al_(2)O_(3)乙二醇基纳米流体黏度最低达0.97 mPa·s,所制备的纳米流体可适合用于流动换热。