木质素酚类单体化合物制备烷烃燃料

通过引入中间小分子化合物,采用傅克烷基化反应,实现了从木质素酚类单体化合物制备长链烷烃燃料.考察了催化剂、醛酮类小分子化合物、反应时间、反应温度、物料比、底物等条件对从木质素酚类单体制备二聚体反应结果的影响,并对得到的木质素酚类二聚体产物进一步加氢还原,得到C_13~19烷烃燃料.结果表明,当物料比n(木质素酚类单体)/n(醛酮类中间小分子)为15:3,以Amberlyst-15为酸性催化剂,在100 ℃的条件下,反应24 h,可以得到68%产率的二聚体化合物(当底物是愈创木酚和丙醛时).将得到的二聚体化合物在270 ℃,4 MPa H₂的不锈钢反应釜中进行加氢反应,3 h后,二聚体化合物完全转化为液体烷烃.提出从木质素单体出发通过引入中间小分子,实现C-C链增长来制备烷烃燃料的合成路线,为木质素的开发和应用提出了新思路与实验基础.     

CHARACTERIZATIONS AND RELATIONSHIPS BETWEEN OUTDOOR AND INDOOR BIOAEROSOLS IN AN OFFICE BUILDING

1.IntroductionBioaerosolsaremicroorganismsorparticles,gases,vapors,orfragmentsofbiologicalorigin(i.e.,aliveorreleasedfromalivingorganism)thatexistintheair.Bioaerosolsareeverywhereintheenvironment.Underfavorableconditions,bioaerosolsareabletogrowandpropagateonavarietyofbuildingmaterialsandindoorsurfaces,causingindoorairpollution.Therefore,owingtotheirubiquitouspresenceinnature,bioaerosolsasapollutionsourcearealmostinevitableinarangeofenclosedenvironmentsandincommunityair(Kodama&McGee,1986;Lig…     

THERMODYNAMIC AND PARTICLE-DYNAMIC STUDIES ON SYNTHESIS OF SILICA NANOPARTICLES USING MICROWAVE-INDUCED PLASMA CVD

1. Introduction1.1 Silica nanoparticles and synthesis methods Silica (SiO2) nanoparticles are widely used in industry asan active filler for polymer reinforcement, a rheologicaladditive in fluids, a free flow agent in powders, and anagent for chemical mechanical polishing during IC (inte-grated circuit) fabrication (Sniegowski & de Boer, 2000).Silica powder is also used for producing silicon carbide(Koc & Cattamanchi, 1998) or opaque silica aerosols (Leeet al., 1995). Many methods can …     

OFDMA中继系统中基于QoS保证的资源分配算法

研究了 OFDMA 中继下行链路通信系统中的动态资源分配问题,提出了一种可以保证用户最低 QoS 需求的资源分配算法.首先在简化资源优化问题的过程中,采用等功率分配方法以降低算法复杂度,然后通过拉格朗日松弛优化方法推导出了子载波分配和中继选择最优解,并在此基础上引入用户速率权衡因子,根据速率权衡因子越大的用户,越具有选择子载波和中继的优先权这一准则进行子载波分配和中继选择.仿真结果表明:新算法能够获得较高的系统容量,同时也能很好地保证不同用户的最低速率需求.     

Synthesis and gelation behaviors of five new dimeric cholesteryl derivatives

Five new diacid amides of di-cholesteryl L-glycinates were designed and prepared.The compounds with linkers containing 0,1, 2,3,or 4 methylene units are denoted as 1,2,3,4,and 5,respectively.Their gelation behaviors in 25 solvents were tested as novel low-molecular-mass organic gelators(LMOGs).It was shown that the length of the linker connecting the two-cholesteryl residues in a gelator plays a crucial role in the gelation behavior of the compound.1 gels 11 of the 25 solvents tested at a concentration lowe...     

Influence of Solid-liquid Interaction and Temperature on the Dynamic Dewetting of a Thin Polymer Film:A Molecular Dynamics Study

Coarse-grained molecular dynamics simulations were carried out to investigate the dewetting behavior of a polymer thin film on partial wetting solid surface at the early stage of the dewetting process. Spontaneous dewetting is initiated by removing a band of strip from both the ends of the liquid polymer film which has achieved equilibrium. The solid-liquid interaction and temperature were varied to show their influence on the dewetting dynamics during dewetting as well as the shape evolution of the liquid ...     

可见光诱导的醇的选择性氧化

在蓝光照射的无金属、 无添加剂的绿色温和条件下, 以2-氯蒽醌为光催化剂, 空气/氧气为氧化剂, 高选择性地将芳族与杂芳族取代的伯醇和仲醇转化为相应的羰基化合物. 实验结果表明, 该催化剂具有较宽的底物适用范围, 为苄基位含氧化合物的合成提供了一条经济、 环保和可持续的新路径, 具有潜在的应用前景.