Poly(α‐methyleneglutarimide)s from radical polymerization of α‐methyleneglutarimides

α‐Methyleneglutaric acid, a metabolite of niacin (nicotinic acid), can be easily converted to its cyclic anhydride. We report here the first conversion of α‐methyleneglutaric anhydride to (a series of) α‐methyleneglutarimides. These monomers can be radically polymerized to the title polymers. These have relatively high glass transition properties compared to the lower homologs derived from itaconimides (α‐methylenesuccinimides). © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1020–1026     

以TEMPO为媒介电化学氧化解聚微晶纤维素的研究

对以2,2,6,6-四甲基哌啶氧化物(TEMPO)为媒介阳极电解解聚微晶纤维素(MCC)的条件及效果进行了研究。研究结果表明,60 g/L MCC在(25±5)℃,含有0.2 mol/L Na2CO3-Na HCO3(p H=10.0)和1.5 g/L TEMPO的电解液中,以石墨电极为阳极0.80 V(vs.Ag/Ag Cl)下恒电位电解会在MCC中引入羧基;当引入羧基量达到2.0mmol/g时,55%的MCC解聚为水溶性低聚糖、纳米纤维素、纤维二糖及葡萄糖,继而在150℃水热反应釜中水解处理,MCC的解聚率可达82%;而未经电化学氧化解聚处理的MCC在150℃水热反应釜中水解处理的解聚率不到1%。     

Weak‐Acid Sites Catalyze the Hydrolysis of Crystalline Cellulose to Glucose in Water: Importance of Post‐Synthetic Functionalization of the Carbon Surface

The direct hydrolysis of crystalline cellulose to glucose in water without prior pretreatment enables the transformation of biomass into fuels and chemicals. To understand which features of a solid catalyst are most important for this transformation, the nanoporous carbon material MSC‐30 was post‐synthetically functionalized by oxidation. The most active catalyst depolymerized crystalline cellulose without prior pretreatment in water, providing glucose in an unprecedented 70 % yield. In comparison, virtually no reaction was observed with MSC‐30, even when the reaction was conducted in aqueous solution at pH 2. As no direct correlations between the activity of this solid–solid reaction and internal‐site characteristics, such as the β‐glu adsorption capacity and the rate of catalytic hydrolysis of adsorbed β‐glu strands, were observed, contacts of the external surface with the cellulose crystal are thought to be key for the overall efficiency.     

Intramolecular cyclization assistance for fast degradation of ornithine‐based poly(ester amide)s

Inspired by the spontaneous cyclization of ornithine in peptides, polyesters containing protected ornithine (Orn) side chains along the backbone were synthesized and shown to degrade rapidly upon deprotection through intramolecular cyclization. A new ornithine‐based poly(ester amide) PEA 1 and a lysine‐based control PEA 2, both bearing the light‐sensitive protecting group o‐nitrobenzyl alcohol (ONB), were synthesized. Tert‐butyl carbamate (Boc)‐protected versions 1‐Boc and 2‐Boc were also synthesized for proof of concept. GPC confirmed that 1‐Boc degrades over 40 times faster than 2‐Boc following deprotection into the designed intramolecular cyclization products. Finally, TEM visualization of particles made from 1 encapsulating iron oxide nanoparticles reveals complete disruption of nanoparticles and release of payload within a day upon UV irradiation. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3783–3790     

Photoinduced unzipping depolymerization of poly(olefin sulfone)s possessing photobase generator and base amplifier

The photoinduced depolymerization of poly(olefin sulfone)s was investigated. Poly(olefin sulfone)s possessing base‐amplifying groups were synthesized. A photobase‐generating compound was mixed with poly(olefin sulfone)s and irradiated with 254 nm UV light. The decomposition ratio was significantly enhanced in poly(olefin sulfone)s that possessed base‐amplifying groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 602–613, 2009     

1,4丁二醇蒸馏底物的回收工艺

在Reppe法生产1,4丁二醇(BDO)的过程中,刮膜式蒸发器会产生一定量的黏稠蒸馏底物。提出了在加压条件下,以稀硫酸为催化剂,对该底物进行水解处理回收BDO并减少废物排放的工艺过程。最优工艺条件为：硫酸质量分数为15%,稀硫酸与底物质量比（配料比）为1.3〖DK〗∶1.0,反应温度为150　℃,反应时间为7 h。通过对水解产物的分离与分析,基于底物的BDO回收率可达39.1%。     

A Comparison of Phenolic Monomers Produced from Different Types of Lignin by Phosphotungstic Acid Catalysts

Herein we studied the chemical structure of different types of lignin samples and the potential to prepare phenolic monomers was illustrated by phosphotungstic acid catalysts. Different types of H/G/S lignin components had different structures. The lignin extracted from poplar had the highest molecular weight and β-O-4 aryl ether contents, followed by pine and straw lignin samples. After depolymerization by PTA catalyst, the yields of phenolic monomers detected was 8.06 wt % (poplar), 5.44 wt % (pine) and 4.52 wt % (straw), respectively. Further, the ratios of H/G/S in the phenol monomers were also different, indicating that the S, G and H types structural units were continuously transformed with each other during the reaction. In our study, the change in the types of lignin samples resulted into an improvement of the distribution of phenolic products, and also the selectivity of phenolic monomers significantly.     

微丝解聚对DNA合成的影响

G_0期细胞在10％血清培养液刺激后向S期行进的早期出现微丝解聚的变化.细胞松弛素B(CB)0.5mg·L~_(-1)使微丝发生部分解聚能加强血清对DNA合成的刺激作用.但随着CB剂量的加大,微丝解聚的加强,便逐步增强对DNA合成的抑制作用.发现用5,10mg·L~(-1)的CB短时间处理G_0期细胞可强烈刺激蛋白激酶C(PKC)活性,虽使微丝暂时完全解聚,但不影响向S期的过渡及DNA的合成.促癌剂TPA(12-tetradecanoyl phorbol-13-acetate)可刺激G_0期细胞PKC活性,并能促进血清对DNA合成的刺激作用,但小剂量CB和TPA促进DNA的合成均依赖于血清的存在。