1种无溶剂合成双乙酸钠的新方法

以醋酸和烧碱为原料,在无溶剂的条件下制备了双乙酸钠,研究了投料比、反应温度和反应时间等因素对产品质量及收率的影响。通过正交实验确定的最佳工艺条件为:投料比n(HAc):n(NaOH)=2.1:1,反应温度110℃,回流反应时间2h,总收率大于97%。产品质量符合国家标准。     

Physicochemical properties and film formation of the chitin hydrocolloid fabricated by a novel green process

Chitin is a valuable natural material, but its applications are limited because of its insolubility in water. Size reduction of natural materials has been found to offer certain benefits, including enhancing dispersibility. We employed media milling to produce a chitin micro-suspension with water as the sole solvent, and to fabricate the chitin film. The particle size and molecular weight were decreased from 96.86 to 21.95 μm and 173 to 75 kDa (M_n), respectively, post milling; however, the degree of deacetylation slightly increased (from 21.26 to 24.31) with milling time. Moreover, limited water-soluble fractions were generated, the quantity (1.5–2.0% d.b.) and molecular weight (M_n 15–34 kDa) of which were characterized. These fractions enabled the formation of a chitin film through the induction of hydrogen bonds. The particle size affected the morphology and mechanical properties of the film. The fabricated chitin film had tunable thickness (61.3–80.7 μm), tensile strength (38.95–64.61 MPa), elongation (0.93%–2.16%), Young's modulus (2994–4246 MPa), WVP (12.04–17.79 g mm/m² day kPa), swelling ratio and surface smoothness. This novel method for fabricating chitin films through aqueous suspension can improve applications of chitin in packaging and particularly fulfill environmentally friendly requirements.     

Continuous reactor for enzymic glycerolysis of butteroil in the absence of solvent

A continuous reactor was evaluated for lipase-mediated glycerolysis of butteroil in the absence of solvent. Lipase (from Pseudomonas cepacia) was immobilized by adsorption, followed by covalent coupling with glutaraldehyde, on a polypropylene sheet which was placed inside the reactor in a spiral wound configuration (axial-annular flow). Substrate feedstock was 2:1 (w/w) butteroil/glycerol and included 1% (w/w) lecithin to promote phase homogeneity. Reactor temperature was maintained at a minimum of 40 °C to prevent substrate/product solidification and attendant reactor fouling. Glycerolysis was found to be most efficacious at 45–55 °C, with 10.5% aqueous glycerol, and at reactor space times approaching 10 h. Under these conditions, >70% butteroil triacylglycerols were converted into a product mixture containing about 70% diacylglycerol and monoacylglycerol at a mass ratio of 2.1–2.2:1.     

Glyceride synthesis in a solvent-free system

Synthesis of partial glycerides in a solvent-free system has been investigated with various acyl donors and glycerol as substrates and a 1,3-specific immobilized lipase to catalyze the reaction. Capric acid was the most efficient acyl donor, compared with ethyl caprate and tricaprin. However, to obtain a high yield of dicaprin and a low amount of tricaprin, ethyl caprate was the acyl donor of choice. The composition of the product mixture was determined by the ratio of ethyl caprate to glycerol; a molar ratio of 3∶1 was optimum for dicaprin synthesis. The water content in glycerol did not influence the final yield of dicaprin, but initial production of capric acid increased with increasing water content. The reaction was found to be controlled entirely by external mass transfer. The yield of diglyceride could be increased from 70 to 90% by lowering the reaction temperature, so that the diglyceride precipitated during the reaction.     

聚酯亚胺F,H级无溶剂滴浸漆的研究

以赛克改性聚酯亚胺树脂为基础树脂，研制出低温快速固化Ｆ、Ｈ级通用无溶剂滴浸漆。ｔ－Ｔ、η－Ｔ特性曲线说明该漆具有优异的工艺特性。热分析、富里叶红外光谱分析结果表明。聚酯亚胺树脂的结构组成是影响无溶剂漆的耐热性、介电性等性能的关键因素。     

封闭型无溶剂聚氨酯超细纤维合成革基布的制备及性能

将聚酰胺6-碱溶性聚酯(PA6-COPET)海岛纤维非织造布与封闭型无溶剂聚氨酯(BSFPU)通过浸渍、碱减量和后整理等工艺制备了BSFPU超细纤维合成革基布。分析和探讨了BSFPU浸渍量对超细纤维合成革基布力学性能和卫生性能的影响,采用电子扫描显微镜对其微观结构进行表征。结果表明:海岛纤维经过减量后形成具有37根纤维且单纤直径约为3 μm的束状超细纤维,BSFPU超细纤维合成革基布形成了近似天然皮革的微观结构。随着BSFPU浸渍量的提高,碱减量过程减量率从31.59wt%降低至28.22wt%;BSFPU超细纤维合成革基布的断裂伸长率和撕裂强度下降;拉伸强度保持不变直到浸渍量大于100wt%时开始下降;透气量从50 086 mL/(m2·s)降低至24 757 mL/(m2·s),透水汽量从790.47 mg/(10 cm2·24 h)下降至488.70 mg/(10 cm2·24 h)。经过测试,BSFPU超细纤维合成革基布能够满足行业检测标准,并且其卫生性能明显优于市售溶剂型聚氨酯超细纤维合成革基布。      

不同沉积物无溶剂纳米石墨烯流体/环氧树脂复合材料阻燃性能对比

分别以沉积碳纳米管(MWCNTs)和羟基锡酸锌的石墨烯片层(GNS)纳米粒子为核、表面活性剂KH560为颈状层、聚醚胺M2070为冠状层,制备了无溶剂(GNS-MWCNTs)@M2070流体及无溶剂(GNS-ZHS)@M2070流体。将质量分数为2.0wt%的两种无溶剂纳米流体分别加入环氧树脂(EP)中,制备了无溶剂(GNS-MWCNTs)@M2070/EP和(GNS-ZHS)@M2070/EP复合材料,并对其热性能和阻燃性能进行研究。锥形量热测试结果表明,纯EP、(GNS-MWCNTs)@M2070/EP、(GNS-ZHS)@M2070/EP的火焰增长速率(FIGRA)值分别为3.682,3.118和4.391kW(m~2·s)~(-1),同时,相比(GNS-MWCNTs)@M2070/EP,含有(GNS-ZHS)@M2070的EP基复合材料较纯环氧树脂具有更低的生烟速率(SPR)、生烟总量(TSR)和一氧化碳释放量(COP)值,说明沉积有羟基锡酸锌的石墨烯片层纳米粒子为核的无溶剂纳米流体对提高环氧树脂阻燃性能更为有效。     

杂多酸催化7-羟基-4-甲基香豆素的无溶剂合成

报道了以杂多酸(H3PW12O40、H3PMo12O40、H8SiW12O42、H6P2W18O40、H4SiW12O40、H6PMo6W6O40)为催化剂,以乙酰乙酸乙酯和间苯二酚为原料,通过Pechmann反应合成标题化合物的方法。探讨了以H4SiW12O40为催化剂时反应温度、催化剂用量、反应时间、原料比诸因素对产品收率的影响。实验表明,H4SiW12O40是合成标题化合物的良好催化剂,在反应温度为130℃,反应时间为50min,n(间苯二酚)∶n(乙酰乙酸乙酯)=1∶1.3,催化剂用量为1.5%(与间苯二酚的物质的量比)时,产品收率75.9%。     

Elucidation of acyl migration during lipase-catalyzed production of structured phospholipids

Elucidation of acyl migration was carried out in the Lipozyme RM IM (Rhizomucor miehei)-catalyzed transesterification between soybean phosphatidylcholine (PC) and caprylic acid in solvent-free media. A five-factor response surface design was used to evaluate the influence of five major factors and their relationships. The five factors—enzyme dosage, reaction temperature, water addition, reaction time, and substrate ratio—were varied on three levels together with two star points. Enzyme dosage, reaction temperature, and reaction time showed increased effect on the acyl migration into the sn-2 position of PC, whereas increased water addition and substrate ratio had no significant effect in the ranges tested. The best-fitting quadratic response surface model was determined by regression and backward elimination. The coefficient of determination (R ²) was 0.84, which indicates that the fitted quadratic model has acceptable qualities in expressing acyl migration for the enzymatic transesterification. Correlation was observed between acyl donor in the sn-2 position of PC and incorporation of acyl donor into the intermediate lysophosphatidylcholine. Furthermore, acyl migration into the sn-2 position of PC was confirmed by TLC-FID, as PC with caprylic acid was observed on both positions. Under certain conditions, up to 18% incorporation could be observed in the sn-2 position during the lipase-catalyzed transesterification.     

无溶剂环氧聚氨酯涂料的研制

合成了端环氧基聚氨酯树脂和端氨基聚氨酯树脂，并利用这两种树脂制备无溶剂环氧聚氨酯涂料。讨论影响涂料性能的各种因素，采用红外光谱分析产物结构与性能的关系。