Indoor heterogeneous photochemistry of furfural drives emissions of nitrous acid

People spend approximately 80% of their time indoor, making the understanding of the indoor chemistry an important task for safety. The high surface-area-to-volume ratio characteristic of indoor environments leads the semi-volatile organic compounds (sVOCs) to deposit on the surfaces. Using a long path absorption photometer (LOPAP), this work investigates the formation of nitrous acid (HONO) through the photochemistry of adsorbed nitrate anions and its enhancement by the presence of furfural. Using a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS), this work also investigates the surface emissions of VOCs from irradiated films of furfural and a mix of furfural and nitrate anions. Among the emitted VOCs, 2(5H)-furanone/2-Butenedial was observed at high concentrations, leading to maleic anhydride formation after UV irradiation. Moreover, the addition of potassium nitrate to the film formed NO_x and HONO concentrations up to 10 ppb, which scales to ca. 4 ppb for realistic indoor conditions. This work helps to understand the high levels of HONO and NO_x measured indoors.     

Elucidation of colour development and microstructural characteristics of Allium sativum fumigated with acetic acid

It has been well known that the greening of Allium sativum cloves could be formed after immersed in acetic acid solution. Nonetheless, no investigation was reported on colour development of A. sativum in response to acetic acid vapour until now. In this study, the brief exposure of A. sativum to acetic acid vapour (200–400 ppm) was combined with controlled atmosphere (5%, 20% and 80% CO₂) packaging storage to break cell membrane and green garlic. The garlic bulbs were fumigated with acetic acid before controlled CO₂ atmosphere packaging for 25 days at 4 °C. Fumigation with 200 ppm acetic acid followed by high CO₂ atmosphere packaging (80% CO₂) facilitated the garlic greening. It was also verified that γ‐glutamyl transpeptidase was involved in garlic greening in present study, and the compromise of glacial acetic acid vapour fumigation and CO₂ gas atmosphere in package stored at low temperature could result in garlic greening as well.     

Fully renewable limonene‐derived polycarbonate as a high‐performance alkyd resin

Limonene‐derived polycarbonate‐based alkyd resins (ARs) have been prepared by copolymerization of limonene dioxide with CO₂, catalysed by a β‐diiminate zinc–bis(trimethylsilyl)amido complex, and subsequent chemical modification with soybean oil fatty acids using triphenylethylphosphonium bromide as the catalyst. This quantitative partial modification was realized via epoxy–carboxylic acid chemistry, affording ARs with higher oil lengths, lower polydispersities and higher glass transition temperatures (T_g) in comparison to a conventional polyester AR based on phthalic acid, multifunctional polyol pentaerythritol and soybean fatty acid. The novel limonene polycarbonate AR and the conventional polyester AR were evaluated as coatings and both the physical drying (without the presence of the oxidative drying accelerator Borchi® Oxy Coat) and chemical curing (with Borchi® Oxy Coat) processes of these coatings were monitored by measuring the König hardness and complex modulus development with time. A better performance was obtained for the alkyd paint containing polycarbonates modified with fatty acids (FA‐PCs), which showed a faster chemical drying, a higher König hardness and a higher T_g in coating evaluation, demonstrating that the fully renewable FA‐PCs are promising resins for alkyd paint applications. © 2019 Society of Chemical Industry     

Insights into biological delignification of rice straw by Trametes hirsuta and Myrothecium roridum and comparison of saccharification yields with dilute acid pretreatment

Rice straw is the most abundant agricultural residue on a global scale and is widely available as feedstock for cellulosic fuel production. However, it is highly recalcitrant to biochemical deconstruction and also generates inhibitors that affect enzymatic saccharification. Rice straw from eastern Arkansas was subjected to dilute acid pretreatment (160 °C, 48 min and 1.0% sulfuric acid) and solid-state fermentation with two lignocellulolytic fungi, Trametes hirsuta and Myrothecium roridum, and their saccharification efficacies were compared. T. hirsuta and M. roridum were tested separately; pretreatment of rice straw with either strain for seven days resulted in 19 and 70% enrichment of its holocellulose content, respectively. However, liquid chromatography analysis of the alkali extracts showed significant differences in cell wall degradation by T. hirsuta and M. roridum. T. hirsuta removed 15% more phenolic compounds and 38% more glucan than M. roridum, while M. roridum removed 77% more xylan than T. hirsuta. Fungal and dilute acid pretreated biomass was then hydrolyzed using Accellerase^® 1500, a saccharification cocktail. Saccharification efficiency of M. roridum was 37% higher than that of dilute acid pretreatment of rice straw, requiring 8% lower enzyme loading and 50% shorter enzymatic hydrolysis duration. Alkali extraction of fungal pretreated biomass also yielded 10–15 g kg⁻¹ of acid precipitable polymeric lignin (APPL), which is a valuable co-product for biorefineries. In comparison to dilute acid pretreatment, fungal pretreatment could be a cost-effective alternative for the degradation of recalcitrant biomass, such as rice straw.     

从7-ADCA生产过程中环境友好的回收苯乙酸

采用新工艺回收7-氨基-3-脱乙酰氧基头孢烷酸(7-ADCA)生产中产生的苯乙酸,并对苯乙酸回收过程中产生的废硫酸进行处理。采用硫酸(9 8%)洗涤二氯甲烷,硫酸与二氯甲烷适宜的体积比为1∶50,洗涤好的二氯甲烷中含苯乙酸4%。蒸馏出二氯甲烷,趁热向熔融苯乙酸中加入母液,降温析出苯乙酸。晾干的苯乙酸为白色鳞片状,含量大于99%,苯乙酸母液补充部分清水套用到下一批析出苯乙酸。废浓硫酸用芬顿试剂氧化,控制80℃氧化4h,双氧水和七水硫酸亚铁重量比为6∶1,废浓硫酸COD下降85%以上。氧化结束后向废硫酸中加入铁粉和双氧水,制得聚合硫酸铁。     

内嵌纳凝胶阴离子交换聚甲基丙烯酸羟乙酯复合晶胶分离苯乳酸研究

采用超声乳化聚合法制备了聚甲基丙烯酸丁酯纳凝胶，然后经结晶致孔法制备了内嵌纳凝胶的甲基丙烯酸羟乙酯纳晶胶，对其接枝功能单体N，N，N-三甲基乙烯基苯甲氯化铵，得到内嵌纳凝胶阴离子交换纳晶胶，用于从发酵液中分离苯乳酸。结果表明：所得纳晶胶具有良好的渗透性能和轴向分散性能，在流速为1 cm·min^-1时，不同配比纳晶胶对牛血清白蛋白的吸附容量为3.9~5.4 mg·ml^-1；将质量比为 8∶2（HEMA∶pBMA）的纳晶胶用于从转化液中分离苯乳酸，所得苯乳酸的纯度达89.24%，回收率93.74%，分离效果好，表明其在生物分离方面有良好的应用前景。     

Preparation and polymerization of isopimaric acid derivatives

Isopimaric acid is a typical rosin compound and can account for 30% of the total mass of slash pine rosin. The molecular structure of isopimaric acid derivatives features an unsaturated double bond at the C13 position, opening up the possibility of their industrial polymerization. In this study, isopimaric acid (95.4%), methyl isopimarate (99.5%), and allyl isopimarate (95.1%) were prepared as highly pure monomers. New experimental results are presented and mechanisms based on the investigation of free-radical polymerization under UV irradiation are proposed. New rosin monomers for potential value-added utilization of woody biomass are also identified. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47817.