高效液相色谱法测定小麦粉及其制品中间苯二酚

建立一种利用高效液相色谱测定小麦粉及其制品中间苯二酚含量的方法。样品经甲醇提取,亚铁氰化钾和乙酸锌沉淀,经C₁₈-Amide柱分离,甲醇/水为流动相洗脱,二极管阵列检测器与荧光检测器串联检测,外标法定量。二极管阵列和荧光检测器的定量结果均具备良好特异性,且在各自线性范围内r^₂＞0.999,定量限分别为1 mg/kg和0.05 mg/kg,回收率在73.0-108.6%之间,RSD<8.2%。建立的方法操作简单、灵敏度高、准确度好,适用于小麦粉及其制品中间苯二酚的测定。     

超重力场下活性炭吸附间苯二酚废水

为了解决传统吸附设备存在设备体积庞大,吸附速率较小等问题,采用旋转填料床(RPB)为吸附设备,活性炭为吸附剂处理模拟含间苯二酚废水,考察了超重力因子、液体流量、温度、p H值和初始间苯二酚浓度对间苯二酚去除率的影响,测定了吸附等温平衡线及动力学数据,并在适宜操作条件下与固定床和磁力搅拌器的间苯二酚去除率进行了对比。结果表明:吸附平衡关系主要服从Freundlich模型,吸附热为14.65 k J·mol~(-1)。得到的吸附间苯二酚的适宜操作条件为:液体流量为50 L·h~(-1),超重力因子为41.30,p H值为5,温度为20℃,废水初始浓度为900 mg·L~(-1),吸附时间为2 h。在此条件下,间苯二酚去除率达到96.86%,较相同操作条件下的固定床和磁力搅拌器而言,去除率分别提高了约20%和14%。吸附过程主要符合准二级动力学方程,相同操作条件下,超重力吸附法的吸附速率常数为2.576×10-3g·mg~(-1)·min~(-1),是传统固定床吸附法与磁力搅拌器吸附法的1.626倍和1.413倍。     

间苯二酚转移加氢制备1,3-环己二酮

用转移加氢法由间苯二酚合成了1,3-环己二酮。适宜的反应条件为:以氢气还原的5%Pd/C 为催化剂,甲酸钠为氢供体,水作溶剂,在70℃反应1 h,1,3-环己二酮的收率为82.1%(HPLC)。考察了 PdCl_2/C的还原方式。催化剂经 XRD 表征确认了其活性组分是原子态的 Pd,初步确定催化剂失活的主要原因是杂质堵塞了活性炭载体中的微孔。     

Studies on rubber‐to‐nylon tire cord bonding

Nylon tire cord (1680/2) was dipped in different adhesives based on resorcinol formaldehyde resin and latex (RFL) and was bonded to natural rubber‐based compounds. The resin‐rubber ratio in the RFL adhesive was optimized. The variation of pull‐through load was studied by varying the drying and curing temperature of the dipped nylon tire cord. RFL adhesive based on vinylpyridine latex was found to have better rubber‐to‐nylon tire cord bonding, compared with the one based on natural rubber latex. Addition of a formaldehyde donor into the RFL adhesive/rubber compound improves adhesion. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1197–1202, 1999     

Fabrication of low-density foam shells from resorcinol-formaldehyde aerogel

Resorcinol-formaldehyde (RF) aerogel chemistry has been used with encapsulation techniques to fabricate low-density, transparent, foam shells. To accomplish this, the gelation time was reduced from several hours to several minutes by the addition of acid following base-catalyzed RF particle growth. However, additional “annealing” of the gel for at least 20 h was needed to maximize crosslinking and minimize swelling in exchange solvents. Increasing the molar ratio of formaldehyde to resorcinol from 2 to 3 also helped to increase crosslinking. Densification of the foam shells due to dehydration during curing was greatly reduced by judicious choice of immiscible oil phases and by saturating the exterior oil phase during the annealing stage. Shells have been produced with diameters of about 2 mm, wall thicknesses ranging from 100 to 200 μm and foam densities approaching 50 mg/cc. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2111–2122, 1997     

Mesoporous hybrid organosilica for stabilizing Pd nanoparticles and aerobic alcohol oxidation through Pd hydride (Pd–H2) species

The hybrid periodic mesoporous organosilica (PMO) with APTES/DAR Schiff-based precursor 3-aminopropyltriethoxysilane (APTES) and 4,6-diacetylresorcinol (DAR) was synthesized in the presence of a structure-directing agent cetyltrimethylammonium bromide and tetraethoxysilane. Then, Pd (II) ions, as well as Pd nanoparticles, were incorporated inside the pore walls of the synthesized APTES/DAR-PMO. The PMO structure was characterized by HRTEM, FT-IR, TEM, FE-SEM, BET, SEM-EDX, low angle XRD, HADAF-mapping, TGA, and atomic absorption spectroscopy (AAS). Subsequently, the as-fabricated green heterogeneous nanocatalysts (Pd-NPs@APTES/DAR-PMO) was used as effective and sustainable catalysts for the aerobic oxidation of benzylic alcohols into their corresponding aldehydes in pure water A high Pd-NPs@APTES/DAR-PMO-catalyzed conversion level of the primary and secondary alcohols was demonstrated. Furthermore, the environmentally friendly catalyst showed outstanding stability, so that readily separated by centrifugation and reused for seven consecutive cyclic terms with good retention of high catalytic activities.