| 1. |
- Andersson, M., et al.
(författare)
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A New Class of Labile Surfactants that Break Down to Non-surface Active Products upon Heating or after a Pre-set Time, without the Need for a pH Change
- 2007
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Ingår i: Tenside Surfactants Detergents. - : Walter de Gruyter GmbH. - 0932-3414 .- 2195-8564. ; 44:6, s. 366-372
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Tidskriftsartikel (refereegranskat)abstract
- A new class of labile surfactants that break down at a controllable rate without the need for a change in pH will be presented. The invention has been patented by YKI Institute for Surface Chemistry, and is based on use of β-keto acids or their salts as surface-active compounds. These surfactants spontaneously break down through decarboxylation, to form an oil-like ketone and CO 2/HCO 3 -/CO 32 - depending on pH. The rate of breakdown can be controlled within a wide range by temperature or by certain additives, but, unlike most cleavable surfactants, a change in pH is not needed. Furthermore the surfactants can be conveniently activated from a stabile precursor just before use, and one (of many possible) precursors of this kind is already available on the industrial scale in the form of a wellknown chemical that is FDA-approved in other, non-surfactant, applications. The compound in question, alkyl ketene dimer (AKD), is produced in large scale by a number of large chemical producers today, and used for hydrophobization of paper. The present article gives an overview of the surfactant chemistry, with focus on recent studies of the kinetics of activation of the surfactant precursor and breakdown kinetics of the labile surfactant at different conditions. Furthermore, possible industrial applications of the surfactant will be discussed, with one example taken from a recent feasibility study performed within the car washing area. © Carl Hanser Publisher.
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| 2. |
- Andersson, N, et al.
(författare)
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Combined emulsion and solvent evaporation (ESE) synthesis route to well-ordered mesoporous materials
- 2007
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Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 23:3, s. 1459-1464
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Tidskriftsartikel (refereegranskat)abstract
- Control over morphology and internal mesostructure of surfactant templated silicas remains a challenge, especially when considering scaling laboratory syntheses up to industrial volumes. Herewereport a method combining emulsification with the evaporation-induced self-assembly (EISA) method for preparing spherical, mesoporous silica particles. This emulsion and solvent evaporation (ESE) method has several potential advantages over classic precipitation routes: it is easily scaled while providing superior control over stoichiometric homogeneity of templating surfactants and inorganic precursors, and particle sizes and distributions are determined by principles developed for manipulating droplet sizes within water-in-oil emulsions. To demonstrate the method, triblock copolymer P104 is used as a templating amphiphile, generating unusually well-ordered 2D hexagonal (P6mm) mesoporous silica, while particle sizes and morphologies were controlled by varying the type of emulsifier and the method for emulsification
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| 3. |
- Hull, Angelica, et al.
(författare)
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Alternative fuel for a standard diesel engine
- 2006
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Ingår i: International Journal of Engine Research. - 1468-0874 .- 2041-3149. ; 7:1, s. 51-63
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Tidskriftsartikel (refereegranskat)abstract
- Alternative fuels have been developed for the commercial diesel products Mkl and EN590. Appropriate additives were selected from a broad range of oxygenates including alcohols, acetals, ethers, esters, and nitrates by a process of systematic elimination. The resulting fuels called Biodiesel 15 meet all existing standards in force for diesel fuel, are stable, and have similar performance characteristics to standard diesel. Significantly Biodiesel 15 is much cleaner than standard diesel with around 30 per cent or more reductions in particulate matter in the exhaust emissions. Carbon dioxide (CO2) emissions are much lower with Biodiesel 15 than with standard diesel products. Other regulated emissions are on a par with Mkl. The fuel consumption of Biodiesel 15 is 2 per cent lower than that of conventional Mkl.
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| 4. |
- Hull, A, et al.
(författare)
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An alternative fuel for spark ignition engines
- 2006
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Ingår i: International Journal of Engine Research. - 1468-0874 .- 2041-3149. ; 7, s. 203-214
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Tidskriftsartikel (refereegranskat)abstract
- Alternative fuels have been developed for standard spark ignition engines. The fuels, which contain generic bio components, maintain all the advantages of ethanol, that is the ability to increase considerably the octane number of gasoline and reduce the amount of harmful pollutants in the exhaust emissions of engines operating on such blends. In contrast to ethanol the new fuel components do not increase the vapour pressure of gasoline-ethanol blends, have a better tolerance to water and do not increase the fuel consumption. The bio component based fuels also compare favourably with mineral sourced octane boosters such as MTBE. Additionally reformulation of the base gasoline becomes unnecessary.
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| 5. |
- Hull, A, et al.
(författare)
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Vapour-liquid equilibrium of binary mixtures. 1. Ethanol-1-butanol, ethanol + octane, 1-butanol + octane
- 2006
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Ingår i: Journal of Chemical and Engineering Data. - 0021-9568 .- 1520-5134. ; 51, s. 1996-2001
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Tidskriftsartikel (refereegranskat)abstract
- The activity coefficients of the binary mixtures ethanol + 1-butanol, ethanol + octane, and 1-butanol + octane were determined at temperatures of (308.15, 313.15, and 318.15) K. The determination of the vapor phase composition at equilibrium was carried out using headspace gas chromatography analysis. Multiple headspace extraction was used to calibrate the headspace gas chromatograph. Comparison of the phase diagrams produced using standard Legendre orthogonal polynomial techniques with phase diagrams from the literature showed good agreement. The composition of the azeotropes were reported, where applicable.
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| 6. |
- Hull, A, et al.
(författare)
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Vapour-liquid equilibrium of binary mixtures. 2. Ethanol + 2,2,4-trimethylpentane, 1-butanol + 2,2,4-trimethylpentane, and ethanol + o-xylene
- 2006
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Ingår i: Journal of Chemical and Engineering Data. - 0021-9568 .- 1520-5134. ; 51, s. 2002-2008
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Tidskriftsartikel (refereegranskat)abstract
- The activity coefficients of the binary mixtures ethanol + 2,2,4-trimethylpentane, 1-butanol + 2,2,4-trimethylpentane, and ethanol + o-xylene were determined at temperatures of (308.15, 313.15, and 318.15) K. The determination of the vapor phase composition at equilibrium was carried out using headspace gas chromatography analysis. Multiple headspace extraction was used to calibrate the headspace gas chromatograph. Comparison of the experimental phase diagrams with phase diagrams from the literature shows good agreement. The composition of the azeotropes are reported, where they exist. The molar Gibbs energy of mixing is reported for all mixtures studied. The infinite dilution activity coefficients are reported for all components of all mixtures. Some thermodynamic models (those of Wilson, NRTL, UNIQUAC, and Flory-Scatchard) have been compared with regard to their suitability for modeling the experimental data.
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| 7. |
- Kizling, J, et al.
(författare)
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On the formation and stability of high internal phase O/W emulsions
- 2006
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Ingår i: Advances in Colloid and Interface Science. - 0001-8686 .- 1873-3727. ; 123-126, s. 295–302-
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Tidskriftsartikel (refereegranskat)abstract
- High internal phase o/w emulsions have been investigated with respect to stability. A series of aliphatic hydrocarbons were used as the oil component. By matching the refractive index of both phases, transparent, concentrated emulsions were produced and these emulsions were found to have the highest long-term stability. The long-term stability of transparent emulsions is attributed to a minimum in free energy at the equilibrium thickness, which, in turn, is related to a reduced attraction over the thin aqueous lamellae. Another factor that contributes to the stability is the absence of the destabilizing mechanisms commonly encountered for ordinary emulsions and foams.
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| 8. |
- Matsson, MK, et al.
(författare)
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Enhanced adsorption of alkyl glucosides on the silica/water interface by addition of amine oxides
- 2005
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Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 21, s. 2766-2772
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Tidskriftsartikel (refereegranskat)abstract
- The effect of adding a small amount of dodecyl dimethyl amine oxide (DDAO) on adsorption on silica from an aqueous solution of dodecyl maltoside (C12G2) has been investigated. The C12G2 itself does not adsorb significantly on silica at any concentration. DDAO on the other hand readily adsorbs in a bilayer-like structure at concentrations approaching cmc, but the adsorbed amount at the concentrations it has been applied in these mixtures is small. In contrast, by combining the two surfactants significant adsorption is observed at concentrations where the adsorption of the pure DDAO, as well as pure C12G2, is very low. We thus see a strong enhancement of the adsorption from the mixed system. The adsorption is suggested to be a two-step process, where individual DDAO molecules first adsorb to the silica surface through electrostatic interactions, and then C12G2 adsorbs at the hydrophobic sites the DDAO tails constitute through hydrophobic bonding. A minimum concentration of DDAO is required to induce adsorption from a solution with constant C12G2 concentration. This concentration is lower for C12G2 solutions below and equal to cmc than above cmc. In addition, the total adsorbed amount shows a maximum around cmc of the mixture for a solution with low DDAO contents. Both these effects are explained by incorporation of DDAO in the C12G2 micelles above cmc, which leads to a desorption of DDAO from the surface.
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