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In this paper we present a comparative life cycle assessment of two processes for the industrial production of methansulfonic acid. The conventional multi-step process for the production of methansulfonic acid is based on the reaction of methanol and hydrogen sulfide to form methanthiol which is used to produce dimethyldisulfate. The dimethyldisulfate reacts further with nitric acid to form methanesulfonic acid. A newly developed process presents the possibility to form methanesulfonic acid directly from methane and sulfur trioxide in a single step at mild conditions. Thus this process enables for the first time the production of a high value chemical through direct activation of methane on an industrial scale. The cradle-to-gate life cycle assessment conducted with the ReCiPe Method revealed that this direct process has a total environmental impact that is 3 times lower than that of the conventional process. The differences resulted from lower energy requirements and alternative reactants used in the direct process. The results therefore demonstrate the potential for methane extracted from natural gas as a greener alternative to oil as a chemical feedstock in the medium term.

Amorphous polysiloxane nano- and microstructures with different shapes can be synthesized from trifunctional organosilane precursors. In the present study, various polysiloxane nano- and microstructures have been produced via a chemical vapor deposition process using ethyltrichlorosilane as precursor. The structure formation and shape are the result of a delicate interplay between temperature, absolute amount of water, and relative humidity. The impact of these reaction parameters during a chemical vapor deposition process has been examined. Experiments have been performed to find a correlation between the reaction conditions and the final shape. Scanning electron microscopy data show that different structures like polysiloxane microrings, microrods, sprouts, nanofilaments, and mixtures of them can be synthesized depending on the reaction conditions. Furthermore, the in-depth comparison of the nanofilament diameters illustrates the dominating influence of relative humidity on structure formation. There is a general trend that at a higher value of relative humidity, structures with a larger diameter are formed independent from the temperature. Here, we clearly differentiate between relative humidity as major and absolute amount of water and temperature as minor important adjusting screws defining the thickness and shape of the resulting nano- and microstructures. Based on these observations, we proof the mechanism of the initial step of structure formation. It is shown that nano- and micro-sized water droplets formed on the substrate surface are likely to act as starting points for structure formation. All results described here strongly confirm the recently published droplet assisted growth and shaping mechanism.

Synthesis of silicone nanofilaments (SNF) on substrates is a successful approach to fabricate superantiwetting surfaces. However, the yield of SNF is usually very low (<< 1 %). After coating reactions, excessive organosilane residues become wastes and are released to the environment. Here, we report a facile, sustainable, high yield strategy to prepare silicone nanofilament coatings by simply exposing trifunctional silane/toluene solution to air. When toluene is exposed to air with relative humidity between 30% and 45%, it can trap a suitable amount of water which enables fast and continuous growth of SNF on different substrates. This new finding not only simplifies the fabrication procedure but also enables the preparation of SNF coatings in a sustainable, high-yield manner. Such a novel technique allows the preparation of superhydrophobic samples on a large scale-hundreds of samples can be prepared in less than 1 day by simply using a mother solution containing a small amount of trifunctional silane.

The synthesis of polysiloxane nanotubes using trifunctional organosilanes is reported. Tubular nanostructures were formed via a chemical vapor deposition technique at room temperature when ethyltrichlorosilane is used or via a liquid phase method when methyltriethoxysilane is used as precursor. In the chemical vapor deposition process the shape of the tubes was controlled by changing the water content in the reaction chamber prior to coating. The diameter varied between 60 and 4000 nm. While in the case of the liquid phase method nanotubes with very high aspect ratios of 800 are produced. Parameters such as length and diameter of the various tubes were investigated using scanning electron microscopy and transmission electron microscopy. Additionally the chemical composition of produced structures was analyzed using attenuated total reflectance infrared and energy dispersive X ray spectroscopy. Glass substrates coated with such structures exhibit extreme superhydrophobic properties.

Chemical composition and shape determine the basic properties of any object. Commonly, chemical synthesis and shaping follow each other in a sequence, although their combination into a single process would be an elegant simplification. Here, a pathway of simultaneous synthesis and shaping as applied to polysiloxanes on the micro- and nanoscale is presented. Complex structures such as stars, chalices, helices, volcanoes, rods, or combinations thereof are obtained. Varying the shape-controlling reaction parameters including temperature, water saturation, and the type of substrate allows to direct the reaction toward specific structures. A general mechanism of growth is suggested and analytical evidence and thermodynamic calculations to support it are provided. An aqueous droplet in either gaseous atmosphere or in a liquid organic solvent serves as a spatially confined polymerization volume. By substituting the starting materials, germanium-based nanostructures are also obtained. This transferability marks this approach as a major step toward a generally applicable method of chemical synthesis including in situ shaping.