Ultrasonic emulsification: basic characteristics,cavitation, mechanism,devices and application

Emulsion systems are widely applied in agriculture, food, cosmetic, pharmaceutical and biomedical industries. Ultrasound has attracted much attention in emulsion preparation, especially for nanoemulsion, due to its advantages of being eco-friendly, cost-effective and energy-efficient. This review provides an overview for readers to the area of ultrasonic emulsification technology. It briefly introduces and summarizes knowledge of ultrasonic emulsification, including emulsion characteristics, acoustic cavitation, emulsification mechanism, ultrasonic devices and applications. The combination of microfluidics and ultrasound is highlighted with huge advantages in controlling cavitation phenomena and emulsification intensification. A novel scale of dμ_C^0.6/μ_D^0.33−E_V is proposed to be able to compare the energy efficiency of emulsion preparation in different devices.     

Biodiesel Feedstock from Emulsions Produced by Aqueous Processing of Yellow Mustard

The multi-stage treatment of stable oil-in-water emulsions produced during non-enzymatic aqueous processing of dehulled yellow mustard flour with cyclic ethers [tetrahydrofuran (THF) and 1,4-dioxane] was investigated to produce a single-phase oil-solvent-water miscella suitable for biodiesel production. While the single-stage treatment of yellow mustard emulsion recovered 97 % and 95 % of the oil by using 4:1 THF:oil and 9:1 dioxane:oil weight ratios, respectively, miscella phases containing more than 7 % water formed, which made them unsuitable as biodiesel feedstock. Multi-stage treatments of the emulsion using lower THF:oil and dioxane:oil weight ratios were further developed to produce oil-solvent-water miscella phases with low water content. While three-stage extraction of emulsions using 0.5:1, 1:1, 1.5:1, and 2:1 dioxane:oil weight ratios did not destabilize the emulsion, three-stage extraction using 0.5:1 and 0.75:1 THF:oil weight ratios effectively recovered over 97 % of the oil, resulting in the production of oil-rich miscella phases containing only 1 % and 1.5 % water, respectively. These miscella phases were analyzed for free fatty acid and phosphorus contents and proved to be excellent feedstocks for the preparation of high-purity methyl esters through single-phase base-catalyzed transmethylation.     

EFFECT OF SURFACTANTS ON KINETICS OF β-CAROTENE PHOTODEGRADATION IN EMULSIONS

The effect of surfactant type on photodegradation kinetics of β-carotene in oil-in-water emulsions has been investigated. The stabilized emulsions of lecithin, sodium stearoyl 2-lactylate (SSL), and polyoxyethylene sorbitan monolaurate (Tween-20) together with a β-carotene solution in corn oil were exposed to illumination. The rate of photochemical degradation was mathematically modeled by regression fitting. The lecithin-stabilized emulsion showed higher light fastness than the other samples. β-carotene photodegradation reaction followed a zero-order kinetic model for oil-based systems and lecithin emulsions, while β-carotene degraded by a first-order reaction in SSL and Tween-20 emulsions. Thermodynamic parameters revealed that water-based samples are more heat sensitive than oil-based samples. An isokinetic relationship was observed between the samples. Moreover, results indicated mixing of SSL and Tween-20 with lecithin leads to better protection of β-carotene than emulsions stabilized with SSL or Tween-20, separately.     

High‐Pressure Homogenization as a Process for Emulsion Formation

Emulsions find a wide range of application in industry and daily life. In the pharmaceutical industry lipophilic active ingredients are often formulated in the disperse phase of oil‐in‐water emulsions. Milk, butter, and margarine are examples of emulsions in daily life. In the metal processing industry emulsions are used in the form of coolants. Emulsions can be produced with different systems. In the following, the process of high‐pressure homogenization is briefly compared to other common mechanical emulsification systems. To facilitate the selection of an emulsification system, the influence of the most important parameters of the emulsion formulation on the resulting mean droplet diameter in the most prevalent continuous emulsification systems is outlined. Subsequently, the most common high‐pressure homogenization systems are discussed in detail. On the basis of data from the literature and own experimental results the described high‐pressure homogenization systems will be compared regarding their attainable mean droplet diameter. It shows that homogenizers with a relatively simple geometry like the patented “combined orifice valve” (Kombi‐Blende) attain the smallest mean droplet diameters. The advantage of the “combined orifice valve” compared to other high‐pressure homogenization systems is not more efficient droplet disruption but rather more efficient droplet stabilization against coalescence immediately after the droplet breakup. The greatest research potential concerning the development of new high‐pressure homogenization systems is still to be seen in improvements of droplet stabilization, i.e., the reduction of coalescence.     

新型蓖麻油基季铵盐的合成及其抑菌性能研究

以蓖麻油酸甲酯为起始原料,与N,N-二甲基-1,3-丙二胺和溴化苄、溴乙烷通过酰胺化反应和季铵化反应生成了新型蓖麻油基季铵盐,其结构经FTIR、1HNMR、13CNMR及ESI-MS进行了确证。采用抑菌圈直径法对目标产物的抑菌性能进行了测试,结果表明,两种季铵盐均有一定的抑菌活性,N,N-二甲基-N-乙基-蓖麻油酸酰胺丙基溴化铵的抑菌活性略强于N,N-二甲基-N-苄基-蓖麻油酸酰胺丙基溴化铵。     

一种新型高分子表面活性剂的破乳作用

探讨了合成的SDE系列共聚物乳液对原油乳状液的破乳作用。通过考察破乳剂用量和破乳温度等对该系列共聚物乳液的破乳作用的影响 ,发现该共聚物乳液对锦州采油厂老三联及锦一联集输站的原油具有良好的破乳效果 ,对孤岛采油厂等地的原油也有一定的破乳效果     

生物基聚氨酯乳液的研究进展

聚氨酯乳液由于性能优异已广泛应用于建筑、皮革、金属防腐等领域的涂装与防护。现有聚氨酯乳液大多为石油基产品，出于可持续发展的需要，伴随生物基原料的快速发展和大规模商业化，生物基聚氨酯乳液获得快速发展。该文综述了合成聚氨酯乳液的生物基原料和助剂，包括生物基异氰酸酯、多元醇、扩链剂、丙烯酸（酯）单体以及其他生物基原材料，同时分析了木质素基、植物油基、非天然单体以及其他生物基聚氨酯乳液的新进展，指出了生物基聚氨酯乳液面临的主要问题，包括原材料供应不足、成本高和产物性能差等，展望了生物基聚氨酯乳液在无溶剂、高生物基含量和多功能等产品的发展前景。     

金属交联型水性聚氨酯乳液的合成

用甲苯二异氰酸酯、聚丙二醇、二羟甲基丙酸等为原料，以锆化合物作交联荆合成金属交联型水性聚氨酯乳液。考察了交联剂用量，NCO／OH值及固含量对乳液粘度及吸水率等性能的影响。实验结果表明：锆盐交联剂用量为0．64％时，乳胶膜的吸水率最低。     

复配型水基乳化液的研制

以400SN润滑油为基础油,加入适量的乳化剂制得乳化油,并加入防锈剂,再与水按一定比例混合形成乳化液。考察了乳化剂的选择、乳化温度、乳化时间、乳化水的用量、防锈剂的种类及防锈剂的用量对乳化液稳定性和分散性的影响,最后确定出最佳配方。最佳工艺如下：乳化剂选用复配型的乳化剂,乳化温度为90—95℃左右,乳化时间为40min,乳化用水量为50％以上,选用复配型防锈剂,防锈剂用量为4％。     

交联型聚氨酯乳液的进展

本文介绍了甲醛、三聚氰胺—甲醛树脂、环氧树脂、氮丙啶、碳化二亚胺,多胺、金田化合物以及接枝等交联法制备交联型聚氨酯乳液。并比较了交联型聚氨酯乳液、热塑性聚氨酯乳櫃以及溶剂型聚氨酯的性能。     

Study on the Stability of DeoxyArbutin in an Anhydrous Emulsion System

The skin-whitening agent, deoxyArbutin, is a potent tyrosinase inhibitor that is safer than hydroquinone and arbutin. However, it is thermolabile in aqueous solutions, where it decomposes to hydroquinone. Pharmaceutical and cosmetic emulsions are normally oil-in-water (o/w) or water-in-oil (w/o) systems; however, emulsions can be formulated with no aqueous phase to produce an anhydrous emulsion system. An anhydrous emulsion system could offer a stable vehicle for compounds that are sensitive to hydrolysis or oxidation. Therefore, to enhance the stability of deoxyArbutin in formulations, we chose the polyol-in-silicone, anhydrous emulsion system as the basic formulation for investigation. The quantity of deoxyArbutin and the accumulation of hydroquinone in both hydrous and anhydrous emulsions at various temperatures were analyzed through an established high performance liquid chromatographic (HPLC) method. The results indicated that water increased the decomposition of deoxyArbutin in the formulations and that the polyol-in-silicone, oil-based, anhydrous emulsion system provided a relatively stable surrounding for the deoxyArbutin that delayed its degradation at 25 °C and 45 °C. Moreover, the composition of the inner hydrophilic phase, containing different amounts of glycerin and propylene glycol, affected the stability of deoxyArbutin. Thus, these results will be beneficial when using deoxyArbutin in cosmetics and medicines in the future.     

乳液型清蜡剂的研究进展及发展趋势

油田清蜡剂在原油开采过程中具有举足轻重的地位。目前油田清蜡剂主要有油基清蜡剂和水基清蜡剂两种,但各有缺点。乳液型清蜡剂是近些年发展起来的新型清蜡剂,它既具有油基和水基清蜡剂的优点,又克服了它们的缺点,从安全、无毒、高效的特点来看,乳液型清蜡剂具有良好的发展前景。目前有关乳液型清蜡剂的综合性报道较少。综述了乳液型清蜡剂的作用机理和研究进展,分析了乳液型清蜡剂的优点和存在的不足,并提出其未来的发展方向及趋势。     

影响冷轧油乳液稳定性工艺因素的研究

为确定某种特定的冷轧油乳化液配制时的工艺条件,研究了复配乳化剂种类、用量、乳化温度、乳化时间等参数对该乳液稳定性的影响规律。研究表明：将醚类与酯类的非离子乳化剂进行乳化,温度50℃,复配乳化剂用量占总乳化液的0.56%,油水体积比1∶19,搅拌时间50min下制得的冷轧油乳化液的稳定性符合我国现行乳化液稳定性行业标准。     

Destabilization of Yellow Mustard Emulsion Using Organic Solvents

An aqueous extraction process was developed consisting of aqueous contact with dehulled yellow mustard flour to recover protein followed by dissolution of the released emulsion in dimethylformamide (DMF) or isopropyl alcohol (IPA) to recover the released oil in the form of single-phase oil–solvent miscellae suitable for industrial applications. Only some 38 ± 3 % of the oil in the yellow mustard emulsion was extracted using DMF even at high weight ratios since DMF is widely miscible with water, preventing separation of the oil from the emulsion. A ternary phase diagram of DMF/oil/water was prepared and confirmed the limited solubility of the oil in DMF in the presence of water. The use of 31:1 IPA:oil weight ratio could effectively recover over 94 % of the oil in the emulsion; however, multiple-stage treatment of the emulsion was proven to be more efficient with lower volumes of IPA required to achieve high oil extraction yields. The results suggest that the optimal conditions for multiple-stage process were four stages using 2:1 IPA:oil weight ratio, with 96 ± 1 % oil recovery from the emulsion.     

室温交联单组分聚氨酯-聚丙烯酸酯乳液的合成

分别合成了带有端酰肼基的自乳化型聚氨酯乳液和带酮羰基侧链的聚丙烯酸酯乳液，将两种乳液混合复配成在室温下可长期稳定储存的乳液，应用时两种树脂的活性基团在室温发生交联反应得到聚氨酯交联的聚丙烯酸酯复合树脂。合成聚氨酯乳液的较好工艺是：反应温度约60℃，反应时间=6h，n（OH)／n(NCO)=0．85，W(—COOH)=3％，二羟甲基丙酸(DMPA)以丙酮提取法加入；分析了乳液的粒径分布和稳定性；用红外谱图证明在室温发生了交联反应 ；测试了复合树脂的某些机械性能和耐溶剂性。     

核壳乳液聚合法制备聚丙烯酸酯-聚氨酯复合乳液

以聚四氢呋喃二醇(PTMG-1000)和异佛尔酮二异氰酸酯(IPDI)为基本原料,二羟甲基丙酸(DMPA)作为亲水扩链剂,甲基丙烯酸-β-羟乙酯(HEMA)作为偶联剂与甲基丙烯酸甲酯(MMA)反应,采用核壳乳液共聚法,制备了聚丙烯酸酯-聚氨酯复合乳液(WPUA);通过红外光谱、透射电镜对WPUA乳液粒子的结构进行观察,探讨了DMPA用量、聚氨酯预聚体R值、聚氨酯(PU)链段与聚丙烯酸酯(PA)链段质量比等因素对乳液外观、粘度、稳定性等性能的影响;结果表明,当DM-PA用量为6份,R值为2.5,PU链段与PA链段质量比为70∶30时,所得WPUA表观性能较为优异。     

Viscosity Reduction of Indian Heavy Crude Oil by Emulsification to O/W Emulsion Using Polysorbate-81

Pipeline transportation is the most convenient means of transportation of crude oil continuously and economically from production site to refinery. However, transportation of heavy crude oil (HCO) through pipelines is difficult due to its high viscosity. The high viscosity of heavy crude oil is mainly due to the presence of poly-aromatic compounds like resins and asphaltenes. Emulsification of HCO using surfactant is believed to be the most favorable technique to reduce the viscosity of HCO for efficient pipeline transport. In the present study, oil-in-water (O/W) emulsion has been formulated using a non-ionic surfactant Polyoxyethylene (5) sorbitan monooleate (PS-81) at different pH, surfactant concentration, and oil content. Box–Behnken response surface method has been used to optimize two responses, apparent viscosity and emulsion stability index (ESI). The optimal values of the parameters found are 75%v/v oil content, 2.5%w/v surfactant concentration, and pH value of 7 at which experimental value of emulsion viscosity is 0.2162 Pa·s, at 150 RPM, with a reduction of viscosity by 95.8% and having ESI of 98.16 after 24 h at 30°C.     

石油醚W/O乳状液及其液膜稳定性

以破乳率为衡量标准,借助显微镜直接观察,探讨了乳状液含水量、表面活性剂用量、乳化时间、乳化强度等因素对石油醚W/O型乳状液体系稳定性的影响。在实验范围内,乳状液含水量的提高及表面活性剂用量的增加,有利于乳状液的稳定;存在较优的乳化时间20min和乳化强度4000rmin-1。选取脂肪烃、芳香烃、混合烃共6种不同油相制备乳状液,对比其稳定性的差异。此外,还初步考察了石油醚W/O/W液膜溶胀和泄漏问题,结果表明该乳状液膜泄漏率低于3.5%,表观溶胀率约为20%。     

Structures of Emulsifier-Water Mesophases Related to Emulsion Stability

The physical properties of absorbed emulsifier films at the surface of oil droplets in an emulsion are an important factor for emulsion stability. When mixtures of a hydrophilic and a lipophilic emulsifier are used in a specific molecular ratio, optimum emulsion stability has been found. Low angle X-ray diffraction data of aqueous bulk solutions of various emulsifier blends forming liquid crystalline phases with a lamellar structure have been investigated. The structure parameters of the lamellar phase: the thickness of the lipid bilayer (da) and the average surface per molecule of emulsifier in contact with water (S) are calculated at various water contents of the systems. The optimum molecular ratio of mixed emulsifiers provides close packing conditions of the hydrocarbon chains in the lipid bilayer, and these properties seem to be related to the rheological properties of surface films and thereby to the stabilizing effect of the emulsifiers in O/W emulsions.     

Biodiesel Production from Mustard Emulsion by a Combined Destabilization/Adsorption Process

Tetrahydrofuran, added to the oil‐in‐water emulsions formed by the aqueous processing of yellow mustard flour, produced oil/water/THF miscellas containing 1–2 % water. The high water content prevented the direct conversion of the system to fatty acid methyl esters (FAME) through a single‐phase base‐catalyzed transmethylation process. Dehydration of these miscellas by adsorption on 4A molecular sieves at room temperature using either batch or continuous fixed‐bed systems successfully reduced the water content to the quality standards needed for biodiesel feedstock (0.3 %). Equilibrium adsorption studies for the uptake of water from oil/THF/water miscella phases at room temperature allowed quantitative comparison of the water adsorption capacity based on the oil and THF concentrations of the miscellas. Batch contact was used to investigate the dominant parameters affecting the uptake of water including miscella composition, adsorbent dose and contact time. The adsorption of the water was strongly dependent on adsorbent dose and miscella oil concentrations. The regeneration of molecular sieves by heating under nitrogen at reduced pressure for 6 h at 275 °C resulted in incomplete desorption of miscella components. The adsorption breakthrough curves in terms of flow rates, initial water and oil miscella concentrations were determined. The dehydrated miscella phases were reacted with methanol in a single‐phase base‐catalyzed transmethylation process with high yields (99.3 wt%) to FAME. The resulting FAME met the ASTM international standard in terms of total glycerol content and acid number.