高效环保型除冰剂CMA的应用及开发

醋酸钙镁盐(CMA)是高效环保型有机酸盐化学品,本文主要介绍了CMA对环境的影响、应用及降低产品成本的工艺路线,并提出利用醋酸废水生产CMA的新工艺。     

CMA类环保型融雪剂的应用研究进展

醋酸钙镁盐(CMA)可替代氯盐,用于机场、高速公路等道路除雪,根除氯害,是一种环保型融雪剂。介绍了国内外融雪剂的品质指标和应用研究进展,重点是利用生物质热解废液替代冰醋酸制备CMA类融雪剂的工艺方法,经济可行。与传统氯盐融雪剂相比,CMA环保型融雪剂腐蚀性低、毒性低、融雪效率高、冰共熔点低、可生物降解等。     

偏苯三酸酐酰氯的合成

以偏苯三酸酐(TMA),二氯亚砜(SOC l2)为原料,CMA为催化剂,1,2-二氯乙烷(DCE)为溶剂,用减压蒸馏方法制备了偏苯三酸酐酰氯(TMAC)。其中,m(TMA)/m(SOC l2)=1.34;CMA、DCE的质量分别为TMA和SOC l2总质量的0.28%,37.5%;反应温度100℃;反应时间10.5 h。用FTIR对TMAC的结构进行了表征,测定其熔点为66.5~67.5℃,HPLC分析其质量分数≥99%。在同一反应器中可循环进行3次合成操作,TMAC的平均收率≥95%,而TMAC纯度不受影响。溶剂和过量的SOC l2可全部回收直接再次使用,循环反应时CMA补加原用量的1/10。该工艺可操作性强,已进入100 t/a中试实验阶段。     

钙镁比对矿粉CMA产物融冰性能和耐腐蚀行为的影响研究

以矿粉和工业废醋酸为原料,合成了5种不同钙镁比的矿粉醋酸钙镁(CMA)。研究了矿粉CMA中钙镁比与融冰性能的关系,考察了矿粉CMA及其与五种常规融冰盐添加剂复配后的三元CMA产物的融冰能力及耐腐蚀性。结果表明,五种矿粉CMA具有良好的耐钢铁腐蚀性;醋酸钙、醋酸镁各自的溶解度和溶解放热共同影响CMA的融冰性能,钙镁比在5～0.45间的矿粉CMA产物20%水溶液的冰点均低于-8.5℃;三元CMA复合物的冰点低于二元CMA产物;KAc对CMA产物的冰点降低和融冰速率贡献最大;尿素、NaNO_2、Ca(NO_3)_2能有效提高三元复合融冰剂的耐腐蚀性能。     

钙镁比对矿粉CMA产物融冰性能和耐腐蚀行为的影响研究

以矿粉和工业废醋酸为原料,合成了5种不同钙镁比的矿粉醋酸钙镁(CMA)。研究了矿粉CMA中钙镁比与融冰性能的关系,考察了矿粉CMA及其与五种常规融冰盐添加剂复配后的三元CMA产物的融冰能力及耐腐蚀性。结果表明,五种矿粉CMA具有良好的耐钢铁腐蚀性;醋酸钙、醋酸镁各自的溶解度和溶解放热共同影响CMA的融冰性能,钙镁比在5～0.45间的矿粉CMA产物20%水溶液的冰点均低于-8.5℃;三元CMA复合物的冰点低于二元CMA产物;KAc对CMA产物的冰点降低和融冰速率贡献最大;尿素、NaNO_2、Ca(NO_3)_2能有效提高三元复合融冰剂的耐腐蚀性能。     

利用醋酸稀溶液生产绿色化学品——醋酸钙镁盐的研究

结合醋酸稀溶液的合理回收和利用 ,以生产绿色化学品———醋酸钙镁盐 (CMA)为目的 ,采用化学萃取将醋酸富集于萃取剂相 ,再用钙镁氧化物为反萃剂 ,反萃生成CMA为工艺路线 ,系统地进行了负载醋酸有机相反萃性能的研究。考察了以三烷基胺 (Alamine 3 3 6) 正辛醇 煤油为萃取剂 ,CaO、MgO及其混合物为反萃剂时 ,反萃剂浓度、负载醋酸初始浓度、相比以及反萃液中醋酸盐初始浓度对反萃率的影响 ,并对反萃过程的机理及CMA中钙镁比例的影响因素进行了讨论。实验结果表明 ,钙镁氧化物可有效地反萃溶剂中的醋酸溶质 ,以生产绿色化学品———醋酸钙镁盐 ;当反萃液pH值大于 6.5时 ,萃取分配常数为 5 ,可有效地预测不同实验条件下的反萃率 ,误差小于± 15 % ;反萃液中Ca∶Mg的值与多种因素有关 ,生产中应注意调节起始的Ca∶Mg比例 ,以保持反萃液中合适的钙镁比例。     

一种低成本环保型融雪剂的制备与性能研究

选择可生物降解的、低成本的醋酸废液（木醋液）为原料,研究了制备低成本的CMA类融雪剂的工艺方法,所得产品为低碳混合羧酸钙镁盐,通过对融雪剂的一系列性能试验表明,其融雪温度低（最低可达-34℃）,融雪效率高（可达208.3 cm^3雪/g融雪剂）,对金属、花草等基本无腐蚀和损害,各方面的性能均优于氯化钠等氯盐融雪剂。     

用异丙苯过氧化氢作氧化剂合成环氧丙烷的新技术(续)

<正>(上接2007年第5期)3.4脱水-氢化工艺使回收PO后的反应液中的CMA先在催化剂存在下脱水转化成α-甲基苯乙烯,然后在氢化催化剂存在下,使α-甲基苯乙烯氢化为CM。     

融雪剂的研究现状及进展

综述了国内外融雪剂的种类、优缺点,环保型融雪剂的技术指标以及研究进展与发展动态,重点阐述了低成本醋酸钙镁盐（CMA）类环保型融雪剂的工艺方法与开发工业废液生产无氯融雪剂技术,使废物得到资源化利用并对应用前景做了展望。     

关于甘蔗糖蜜酒精废液物质及其应用

废物综合利用是改善环境、提高经济效益、促进国民经济可持续发展的重大举措。甘蔗糖蜜酒精废液(以下称为CMA废液)在我国每年超过600万吨,含固形物60万吨以上,是一种有待开发利用的废物资源。CMA废液含多种有利用价值的物质,尤其是其干固物中含水溶性腐植酸类物质45％,可在工农业上作多种用途。     

木醋液制环保型融雪剂技术与应用研究

木醋液的应用研究主要围绕农业、林业、养殖业、新型环保型融雪剂等方面。重点论述了木醋液制备醋酸钙镁盐（CMA）环保型融雪剂技术。醋酸钙镁盐类融雪剂是替代高速公路除冰剂（氯化钠）而开发的一种新型环保型产品,对公路基础设施中的混凝土与金属的腐蚀性小,基本上对土壤和水源不造成污染,同时具有水溶性好,熔点低,可生物降解等优点。以木醋液为原料,可制得低成本的醋酸钙镁盐类融雪剂,使木醋液变废为宝,既达到了生物质资源的二次利用、又减少了对环境的污染,具有较好的经济效益和社会效益。     

苯丙烯醛改性煤沥青的工艺研究

在硼酸的作用下,用苯丙烯醛对煤沥青进行改性。研究了反应物配比对改性沥青甲苯不溶物含量、残炭率及软化点的影响,并研究了反应时间对残炭率和软化点的影响。结果表明:改性沥青的甲苯不溶物含量及残炭率随苯丙烯醛含量的增加先增大后减小,软化点随苯丙烯醛的增加而减小。随着反应时间的延长,软化点逐渐升高,残炭率先增大后减小。当硼酸与煤沥青质量分数为7%,苯丙烯醛与煤沥青质量分数为10%,并且反应时间为3 h时,改性效果最好,此时改性沥青的残炭率为68%。     

肉桂酸生物合成苯乙酮微生物的筛选及反应条件优化

以肉桂酸为碳源,从肉桂种植区土壤中富集筛选获得了一株能将肉桂酸高效、高选择性地转化为苯乙酮的菌株JX66,经鉴定,菌株JX66为越南伯克氏菌(Burkholderia vietnam iensis)。研究表明,在肉桂酸质量浓度为5 g/L,反应体系的初始pH=9.0,28~30℃,反应48 h,Burkholderia vietnam iensisJX66催化肉桂酸转化为苯乙酮的转化率为83.5%;反应产物为单一的苯乙酮。     

Influence of Preparation Modes on Pt–Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

Pt–Ni/CNTs catalysts are prepared by different impregnation techniques and different reduction methods (H₂, HCHO, and KBH₄) for the selective hydrogenation of cinnamaldehyde (CMA) to hydrocinnamaldehyde (HCMA) and investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (H₂-TPR) techniques. The results show that the catalytic selectivity and activity of the Pt–Ni/CNTs catalysts would significantly be improved by using KBH₄ as a reducing agent, due to the electronic synergetic effect of Pt–Ni–B, and 96% for conversion of CMA and 88% for selectivity of HCMA are obtained over Pt–Ni/CNTs catalyst reduced by KBH₄. Furthermore, the hydrogenation rate of CMA and selectivity of CMA to HCMA over Pt–Ni/CNTs catalyst are significantly improved in the presence of trace base or acid promoters again. The best result (92% for conversion of CMA and 96% for selectivity of HCMA) is obtained when NaOAc is used as base promoter.     

Studies on graft copolymerization of cyclohexyl methacrylate onto 1,2-polybutadiene

The free radical grafting of cyclohexyl methacrylate (CMA) onto 1,2-polybutadiene (1,2-PBD) in benzene solution at 60°C was studied. The graft copolymer was characterized by IR, NMR, DSC, and intrinsic viscosity measurements. The polymerization of CMA shows normal kinetic behavior when the PBD concentration is kept below 1.0 monomer mol/L. The rate of grafting was determined at different reaction times, monomer concentrations, initiator concentrations, backbone concentrations, temperatures, and concentrations of the zinc chloride additive. The performance of the graft copolymer used as adhesive was also investigated for bonding of PVC/PVC film.     

Comparative Study of the Modification of Coal Tar Pitch for Higher Carbonization Yield and Better Properties

Parent coal tar pitch（CTP） was modified with boric acid（BA）, cinnamaldehyde（CMA） and the mixture of BA and CMA, respectively. The parent CTP and three modified CTPs were characterized by elemental analysis, thermogravimetric analysis, Fourier transform infrared（FT-IR） spectroscopy and scanning electron microscopy. The four samples were carbonized at different temperatures and resultant carbonized products were characterized by FT-IR spectroscopy, X-ray diffraction and polarized-light microscopy. The results show that the morphologies and carbonization behaviors of the parent CTP and modified CTPs are quite different. The carbonization yield of the CTP modified with the mixture of BA and CMA is higher than that of CTP modified with BA or CMA only. In addition, the modification of CTP with 7 g of BA and 10 ml of CMA results in an increase in carbonization yield by 5.64%. During the pyrolysis of modified CTPs, the dehydration of BA or the distillation of CMA occurs at the temperature lower than 300 °C, and methyl and methylene groups of the modified CTPs disappear gradually as temperature rises. Furthermore, the modification of CTP by the mixture of BA and CMA results in more intensive mesophase spheres than other modified CTPs, and the modified CTP is easier to be carbonized to form graphitic carbon.     

电沉积组分调制合金的技术进展及工艺设计

组分调制合金的多层膜结构中由于存在薄膜效应,界面效应,耦合效应和周期性效应而使特性增强或产生出新颖的特性,利用电化学方法可制造结构可控的组分调制合金新材料,综述了电沉积组分调制的技术进展,并分析了电解液组分,pH值,温度,搅拌速率,脉冲电位和时间等电 沉积工艺参数对多层膜组分,结构和调制波长的影响。     

Cellulose monoacetate/polycaprolactone and cellulose monoacetate/polycaprolactam blended nanofibers for protease immobilization

Enzymes can be used multiple times when they are immobilized on a support. More enzymes can be immobilized on a surface when nanofibers are used as a supporting surface because the specific surface area increases tremendously. In this regard, polycaprolactam/cellulose monoacetate (PA6/CMA) and polycaprolactone/cellulose monoacetate (PCL/CMA) blended nanofibers (NFs) were prepared via an electrospinning process. Protease enzymes were immobilized on neat PA6, PCL, PA6/CMA, and PCL/CMA nanofibers and glutaraldehyde (GA) activated analogs through the physical adsorption method. The immobilized enzyme activity was measured by using a casein substrate, and the results were compared with free enzyme activity. Among all of the samples, the highest immobilization yield of about 82% was obtained with GA‐activated neat PCL NF samples. The best remaining activity of the immobilized enzymes on pure CMA NFs was found to be 59% after seven reuses. Even after nine reuses, enzyme activities are still observed on the CMA NF samples. It was expected that the addition of CMA in PCL and PA6 NFs would increase the reusability number to reach the reusability of CMA NFs, but it was not significantly enhanced. If CMA chains could be mostly collected on the sheath or close to the sheath of the NFs during the electrospinnig process, this target could be achieved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45479.     

Prediction of protein residue contacts with a PDB-derived likelihood matrix

Proteins with similar folds often display common patterns ofresidue variability. A widely discussed question is how thesepatterns can be identified and deconvoluted to predict proteinstructure. In this respect, correlated mutation analysis (CMA)has shown considerable promise. CMA compares multiple membersof a protein family and detects residues that remain constantor mutate in tandem. Often this behavior points to structuralor functional interdependence between residues. CMA has beenused to predict pairs of amino acids that are distant in theprimary sequence but likely to form close contacts in the nativethree-dimensional structure. Until now these methods have usedevolutionary or biophysical models to score the fit betweenresidues. We wished to test whether empirical methods, derivedfrom known protein structures, would provide useful predictivepower for CMA. We analyzed 672 known protein structures, derivedcontact likelihood scores for all possible amino acid pairs,and used these scores to predict contacts. We then tested themethod on 118 different protein families for which structureshave been solved to atomic resolution. The mean performancewas almost seven times better than random prediction. Used inconcert with secondary structure prediction, the new CMA methodcould supply restraints for predicting still undetermined structures.