Synthesis of multi-alkylpolyamines and their performance as flow improver in crude oil

In this work, three multi-alkyl polyamines, i.e., pentahexadecyl diethylenetriamine (PHDETA), hexahexadecyl triethylenetetramine (HHTETA) and heptahexadecyl tetraethylenepentylamine (HHTEPA), were synthesized and evaluated as pure flow improvers for crude oil. Under certain conditions, PHDETA, HHTETA and HHTEPA were able to improve the flow properties of L401 crude oil samples by reducing the viscosity of the crude oil by 97.5%, 94.3% and 97.1%, respectively. The three synthesized alkyl polyamines PHDETA, HHTETA and HHTEPA were able to reduce the viscosity of L1316 crude oil to a maximum of 94.3%, 93.7% and 94.9%, respectively. The pour point of L401 crude oil could be greatly reduced by 3.1 °C, 3.3 °C and 3.4 °C with PHDETA, HHTETA and HHTEPA, respectively. The pour point of L1316 crude oil with PHDETA, HHTETA and HHTEPA was strongly decreased by 2.8 °C, 2.9 °C and 3.2 °C, respectively. Photomicrographs showed the co-crystallization of L401 and L1316 crude oil in the presence of PHDETA, resulting in the formation of a non-close-packed network of wax crystals. The multi-alkyl polyamines have multiple alkyl side chains that extend in different directions into the oil phase and can co-crystallize with the wax molecules, allowing the wax crystals to disperse.

Saponin surfactants used in drug delivery systems: A new application for natural medicine components

Saponins are a group of compounds widely distributed in the plant kingdom. Due to their amphiphilic characteristic structure, saponins have high surface activity and self-assembly property and can be used as natural biosurfactants. Therefore, saponin has become a potential drug delivery system (DDS) carrier and has attracted the attention of many researchers. Increasing studies have found that when drugs combining with saponins, their solubility or bioavailability are improved. This phenomenon may be due to a synergistic mechanism and provides a potentially novel concept for DDS: saponins may be also used for carrier materials. This review emphasized the molecular characteristics and mechanism of saponins as carriers and the research on the morphology of saponin carriers. Besides, the article also introduced the role and application of saponins in DDS. Although there are still some limitations with the application of saponins such as cost, applicability, and hemolysis, the development of technology and in-depth molecular mechanism research will provide saponins with greater application prospects as DDS carriers.

Interfacial Behaviour of Saponin Based Surfactant for Potential Application in Cleaning

Amphiphilic molecules reduce the surface tension of the aqueous medium and are widely used in industrial and domestic applications due to this property. Nowadays, amphiphilic molecules on a natural basis are in great demand to replace synthetic surfactants and thus contribute to the reduction of environmental problems. Approximately 60% of the material based on surfactants end up in seawater, which is dangerous for aquatic life. We are proposing a new type of material, which is a surfactant on a natural basis, biodegradable and an environmentally friendly alternative. Here we focus on tea saponin and study its properties such as surface tension, foaming, skin mildness, cleanability. Tea is naturally acidic, reduces the surface tension to 31.4 mN/m, has a greater foaming power, is ultra-mild to skin, and has excellent cleaning properties. The results show that tea has excellent surface activity, which is why tea can be used as a green substitute for synthetic surfactants.

Surface activity and foaming properties of saponin-rich plants extracts

Saponins are amphiphilic glycosidic secondary metabolites produced by numerous plants. So far only few of them have been thoroughly analyzed and even less have found industrial applications as biosurfactants. In this contribution we screen 45 plants from different families, reported to be rich in saponins, for their surface activity and foaming properties. For this purpose, the room-temperature aqueous extracts (macerates) from the alleged saponin-rich plant organs were prepared and spray-dried under the same conditions, in presence of sodium benzoate and potassium sorbate as preservatives and drying aids. For 15 selected plants, the extraction was also performed using hot water (decoction for 15 min) but high temperature in most cases deteriorated surface activity of the extracts. To our knowledge, for most of the extracts this is the first quantitative report on their surface activity. Among the tested plants, only 3 showed the ability to reduce surface tension of their solutions by more than 20 mN/m at 1% dry extract mass content. The adsorption layers forming spontaneously on the surface of these extracts showed a broad range of surface dilational rheology responses - from null to very high, with surface dilational elasticity modulus, E' in excess of 100 mN/m for 5 plants. In all cases the surface dilational response was dominated by the elastic contribution, typical for saponins and other biosurfactants. Almost all extracts showed the ability to froth, but only 32 could sustain the foam for more than 1 min (for 11 extracts the foams were stable during at least 10 min). In general, the ability to lower surface tension and to produce adsorbed layers with high surface elasticity did not correlate well with the ability to form and sustain the foam. Based on the overall characteristics, Saponaria officinalis L. (soapwort), Avena sativa L. (oat), Aesculus hippocastanum L. (horse chestnut), Chenopodium quinoa Willd. (quinoa), Vaccaria hispanica (Mill.) Rauschert (cowherb) and Glycine max (L.) Merr. (soybean) are proposed as the best potential sources of saponins for surfactant applications in natural cosmetic and household products.

Synergistic Effect of Rhamnolipid and Saponin Biosurfactants on Removal of Heavy Metals from Oil Contaminated Soils

In this study synergistic effect of the biosurfactants saponin and rhamnolipid on the removal of the heavy metals such as vanadium, nickel and chromium from contaminated soil was investigated. Washing solutions were prepared by using different concentrations of two biosurfactants. In this work, the optimum HLB value of the extraction process of about 10.5 was obtained for the mixture of 62.5 % rhamnolipid and 37.5 % saponin. According to our results, at the optimal HLB value, a maximum removal was obtained for Ni of 87 %, Cr of 71 % and Va of 70 %. Our results also showed that the efficiency of heavy metals decreased with increasing the pH value of system. The optimum pH value of heavy metals removal was 5. According to the results of this research saponin and rhamnolipid have the synergistic effect on the heavy metals removal and it seems to be a good alternative to chemical surfactants for environmental applications.

Investigation of the anti-inflammatory properties of Calendula nanoemulsion on skin cells

Essential oils and extracts are used in the medical field, perfumes, cosmetics and food additives. Calendula belongs to a composite family and contains small amounts of volatile essential oils, saponins, and so on. Due to these properties, there is a growing inclination and interest to use this material in the hygiene and cosmetics industry. In this study, the production of nanoemulsions was conducted using Tween 80 and Span 80 as emulsifiers. The optimum operation condition was determined using the design expert method. The obtained results showed that the optimum values of the emulsification process were 9·1, 3·4%, 4·7%, 3 min and 102 nm for hydrophile–lipophile balance (HLB), surfactant concentration, extract concentration, sonication time and nanoemulsion size, respectively. Sonication time and HLB were the main factors in the emulsification process. Also, by applying three samples (3, 5 and 7% of Calendula extract) on albino rats, the authors found that all samples had positive effects for healing and ameliorating the wounds. According to the results, the nanobioemulsion of Calendula extract showed an anti-inflammatory effect on skin cells. Therefore, Calendula nanoemulsion should be proposed to cosmetic and pharmaceutical industries instead of chemical and synthetic nanomaterials.

Synergistic Effect of Saponin and Rhamnolipid Biosurfactants Systems on Foam Behavior

In this study, the synergistic effect of saponin and rhamnolipid biosurfactant on foam properties at an air-water interface was investigated. In order to reach the optimum hydrophilic lipophilic balance (HLB) value, samples of 2 wt% of rhamnolipid and saponin biosurfactants with different HLB values (9.6, 10, 10.4, 10.8, 11.2, 11.6, and 12) in 5 ml of DI water were prepared. Results showed that the optimum HLB value of the microemulsion system was 10.8 for the mixture of 84% rhamnolipid and 16% saponin. At that optimum HLB value and a total surfactant concentration of 2 wt%, the maximum foaming ability and foam stability of the mixed system was 48 mm and 72 min respectively. During the experiment, it was observed that at optimum HLB value the foaming ability of the system increased by increasing the concentration of rhamnolipid and saponin. Comparing the foaming ability and foam stability of biosurfactant system with the properties of SDS, Tween80 and Span80 showed that the biosurfactants have a good foaming ability. The CMC value of the biosurfactant mixtures at the optimum HLB value was lower than that of other synthetic surfactants. The results show that, the biosurfactant mixtures had a synergistic effect on foaming ability and foam stability compared to the individual biosurfactants and synthetic surfactants. Therefore, the mixture of rhamnolipid and saponin is proposed as a potential alternative for detergent, cosmetic and petroleum industry.