分子氧化及光电催化氧化对石油Pickering乳液的破乳研究进展

石油开采、集输、加工过程中会面临复杂的工况条件,原油中的天然表面活性剂与人工添加乳化剂以及纳微米固体颗粒共同形成石油Pickering乳液,使得油水体系呈稳定的水包油（O/W）、油包水（W/O）或多重乳化状态。油水乳状液作为注水采油的主要产物,其高效破乳是石油工业链条中的普遍需求。目前对于石油Pickering的破乳仍然借鉴普通油水乳液的方法,而对于成因复杂的油水乳状液,以去除成膜乳化剂为目标的氧化破乳法比传统破乳法的效果更佳。为此,本文基于高效的氧化破乳机制,介绍了石油Pickering乳液的特点及危害,与非氧化反应类型的传统化学破乳法进行对比,综述了分子氧化、光催化氧化、电化学氧化三类技术对于不同来源及特征的油水乳状液的破乳进展。通过对每种方法的机理过程、应用实例、优缺点等方面详细分析,总结了分子氧化、光催化氧化、电化学氧化在石油Pickering乳液破乳中的局限性,并对今后如何实现石油Pickering乳液精准破乳提出展望。     

利用油溶性色素测定搅打乳状液中游离脂肪的方法研究

研究了一种测定搅打乳状液中游离脂肪的新方法，油性色素法。基于油溶性色素油红-O只溶于游离态脂肪的原理建立了测定搅打乳状液中游离脂肪的实验方法并推导出理论计算公式。研究了方法的可行性，结果表明油红-O对典型的食品乳化剂(包括乳清蛋白、酪酝酸钠、Tween-60)和由这些乳化剂稳定的乳状液没有影响。利用该方法测定典型的搅打乳状液植脂鲜奶油中脂肪球部分聚结，经研究证实，油性色素法与传统的溶剂萃取法和浊度法相比，能实际地反映搅打乳状液在搅打过程中脂肪球发生部分聚结的程度，并具有测定结果重现性好、操作方便的优点。     

RHEOLOGY,PARTICLE SIZE DISTRIBUTION,AND ASPHALTENE DEPOSITION OF VISCOUS ASPHALTIC CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

The rheology of an asphaltic heavy crude oil-in-water emulsions stabilized by an anionic (RN) and a nonionic (TEP) surfactants individually or in a mixture has been studied. The investigated crude oil has a non-Newtonian, time dependent, shear thickening, rheopectic behavior with a relatively high yield stress. The relatively high yield stress of this crude oil is attributed to the presence of a relatively high asphaltene and resins content. The viscosity ofhe crude oil decreases when it is emulsified with synthetic formation water in the form of an oil-in-water type of emulsion using a nonionic or an anionic surfactant. It has been found that, the maximum oil content required for forming an oil-in-water emulsion of acceptable viscosity is the 60% oil-containing emulsion. However, the 70% oil-containing emulsion is not an oil-in-water type of emulsion but it is rather a complicated mixture of oil-in-water-in-oil type of emulsion. The presence of the anionic and the nonionic surfactants together has a synergistic effect in decreasing the total surfactant concentration required to stabilize the emulsion and to form low viscosity emulsion. It has been emphasized that the nonionic surfactant has a positive contribution in forming emulsions with low viscosity. Meanwhile, the anionic surfactant contributes in stabilizing the emulsion at lower concentrations. Flocculation point measurements showed that the added surfactants caused no sign of asphaltene deposition. This implies that it is safe to use the investigated surfactants in forming oil-in-water emulsion for viscous asphaltic crude oils without any fear of asphaltene deposition.     

Treatment of fuel peat to enhance moisture removal

Dewatering of peat by mechanical pressing can be greatly improved by treatments, such as addition of electrolytes and freezing and thawing, which break down the colloidal peat structure. Particularly, by addition of 9.4% lime to peat, followed by freezing, thawing and pressing at ≈8.27 MPa, the moisture content can be reduced from 90% to ≈50%. The improvement gained is commercially advantagous.     

Silicones—Basic chemistry and selected applications

The objective of this review is to provide a working knowledge of the chemistry of silicone compounds to the practicing chemist. Although silicone compounds have been known for over 50 yr, the chemistry of these materials remains elusive to the average formulating chemist. This is indeed unfortunate, since the chemistry of the silicon atom and resulting silicone compounds is every bit as wide in scope and rich in content as the chemistry of the carbon atom and the resulting surfactant chemistry upon which it is based. Only in the past decade has the use of silicone as a hydrophobic building block for the preparation of surfactants become common. The recent trend to combine silicone, fatty and polyoxyalkylene moieties in the same molecule has resulted in a plethora of new compounds with new properties.     

Percutaneous absorption of parabens from cosmetic formulations

Absorption through human skin of a series of six p -hydroxy-benzoates (parabens) was studied in vitro. A diffusion chamber was used, where the receiving phase was a physiological solution of albumin. Maximum fluxes and permeability constants of the parabens were measured from different vehicles representing hydrophilic and lipophilic phases, and from different types of common commercial cosmetic emulsions, each containing a known quantity of a single member of the series. Significant skin absorption was observed, depending upon the partition coefficient (log P octanol/water) of the permeant, composition and time of storage of the emulsions. Fluxes from all types of emulsions were higher for methyl paraben and decreased with the increasing lipophilic character of the preservative. Comparatively, fluxes from oil/water emulsions were higher than from water/oil emulsions. Moreover, a clear dependence of preservatives'percutaneous absorption on the time of storage was observed, the fluxes becoming constant after about three months after the time of preparation. The relationship between preservative activity and percutaneous absorption is discussed.     

The influence of fatty alcohols on the structure and stability of creams prepared with polyethylene glycol 1000 monostearate/fatty alcohols

Liquid paraffin in water emulsions stabilized by PEG 1000 monostearate and alcohols cetostearyl (c/s) myristyl (C₁₄), cetyl (C₁₆) or stearyl (C₁₈) and ternary systems prepared by dispersing each fatty alcohol and surfactant in water were examined during 30 days using a Ferranti-Shirley cone and plate viscometer. Microscopical diffusion experiments investigated interaction between PEG 1000 monostearate solution and each alcohol at high and low temperature.
The rheological properties of each ternary system and corresponding emulsion were similar. Formulations prepared from pure C₁₄, C₁₆ or c/s alcohols were semisolid immediately after preparation. Flow curves were in the form of anticlockwise hysteresis loops with spur points. On ageing for 24 h, structure built-up over a time scale similar to that observed in diffusion experiments, so that apparent viscosities increased. However, on further ageing the pure C₁₄ and C₁₆ alcohol systems were not as stable as those prepared with c/s alcohol. In contrast, the pure C₁₈ systems were mobile liquids and the emulsion cracked within days. This correlated with diffusion experiments where little interaction was observed between stearyl alcohol and PEG 1000 monostearate.
Emulsion consistencies and stabilities were related to the low temperature structures formed in the continuous phases.
L'influence des alcools gras sur la structure et la stabilité des crèmes préparées à partir de systèmes monostéarate de polyéthylène glycol 1000/alcools gras.     

炮孔积水对散状乳化炸药性能的影响

含水炮孔的爆破问题一直为爆破工作者所关注，本文借助高速摄影仪器，并通过试验对散状乳化炸药的装药及其影响进行了探讨。     

Disulfide Bond Formation Affects Stability of Whey Protein Isolate Emulsions

The viscosity and degree of flocculation of 20 wt% n-hexadecane oil-in-water emulsions stabilized by whey protein isolate (1 wt% WPI in 0.05M phosphate buffer, pH 7.0) increased as the emulsions aged. These effects were reduced when N-ethylmaleimide, a sulfhydryl blocking agent, was added to the emulsions immediately after homogenization, but were not completely eliminated. Gel electrophoresis (SDS-PAGE) showed an increase in the extent of intermolecular disulfide bond formation between proteins absorbed at the droplet interface with time. Floes were probably formed initially by noncovalent bonding or bridging flocculation, and then stabilized by disulfide bonds between proteins absorbed to different droplets.     

彩色负片利用排列结构提高感光度

本文综述了近些年来，在采用改变多层彩色胶片乳剂层排列结构的新途径，以提高彩色负片的感光度。着重介绍了通过在分色感光层的下面，再涂一层卤化银颗粒较细小的乳剂层，引起漫反射光提高该分色感光层感光度的原理和实效。文中详细地阐明了下层乳剂层的厚度和卤化银颗粒大小对上层乳剂层感光度的影响。