In the context of carbon-neutral production, sustainable H2 will become a crucial resource and key element for the transformation of the chemical industry. In this study, the potential of inter-plant H2 networks is demonstrated in the context of methanol and its derivatives. In order to assess the impact of the exploitation of untapped H2-rich waste streams, a process chain for the directly coupled production of CO2-based methanol and formaldehyde was chosen. It is shown that including a H2 loop between a modified silver catalyst processes for formaldehyde production and the feed stream of CO2-based methanol synthesis results in an increase in process performance as well as economic benefits. Directly coupled production leads to utilization ratios of 98% and 99% for CO2 and H2, respectively, while exergy efficiencies are improved by up to 4.5%pt. Economic evaluation shows that improved H2 management not only yields savings in operational expenditures but also lowers capital investments. Over a wide range of assumed H2 prices, small decentralized plants become more competitive when both subprocesses are directly linked. Minimum selling prices between 836 & euro;& sdot;t-1 and 852 & euro;& sdot;t-1 are reached for methanol in integrated plants, corresponding to a decrease of 3 to 13.5%pt when compared to separately operated CO2-based methanol synthesis followed by conventional formaldehyde production.

Due to modern civilization's dependence on finite fossil resources, there is a growing need to implement a circular economy. Catalyzed acetalization reactions could contribute to achieve this goal. In such reactions, a wide variety of aldehydes and alcohols can be converted into acetals, which are known for their good recyclability and non-toxicity. Hence, this work focused on the utilization of acetalization reactions to produce novel and facile degradable building blocks for the chemical industry. The educts employed were the lactic acid derivatives ethyl lactate and butyl lactate, as well as formaldehyde, an important C1 bulk chemical that can potentially be produced from green methanol. The synthesis of functionalized oxymethylene ethers (f-OMEs) using the lactic acid derivatives and formaldehyde was performed for the first time. Based on an initial catalyst screening, the cheap and eco-friendly clay material montmorillonite K10 was employed as the catalyst with the highest selectivity for the desired acetals. The different reactivities of the tested solid acid catalysts are discussed. The conversion values reached up to 60%, and the selectivity for f-OMEs reached up to 70%, depending on the reaction conditions. Catalyst screening and experiments covering the relevant reaction conditions were initially carried out in a batch reactor. Subsequently, the process was successfully implemented in a continuously operating fixed-bed reactor, demonstrating the first steps for scale-up and further selectivity control. After a systematic study of the varying reaction conditions, a reaction network was proposed, and a kinetic model to estimate product distributions was developed. The validation of the model showed that the conversion prediction was mostly within a relative deviation of ±30%. The model exhibited good applicability to batch and fixed-bed reactors, making it a useful tool for process upscaling. A solvent-free and scalable production process for f-OMEs was developed, and the novel substances were characterized.

The heterogeneously catalyzed co-oligomerization of ethylene, propylene, and iso-butylene was studied focusing on the production of gasoline and kerosene. Silica-alumina catalysts were employed with and without nickel loading. Initially, the homo-oligomerization of iso-butylene was studied employing a series of catalysts and varying reaction conditions. Due to the high reactivity of iso-butylene, conversion was almost quantitative and selectivities to kerosene reached 96% while selectivities to gasoline reached 83%. Subsequently, co-oligomerization of iso-butylene with ethylene and propylene was investigated. Employing nickel-loaded silica-alumina catalysts, all olefin species can be converted, despite the very different reactivity. Selectivities to kerosene and gasoline were up to 92% and 83%, respectively. It is shown that iso-butylene can be easily separated from such olefin mixtures by oligomerization, due to its much higher reactivity compared to propylene and ethylene. A long-term run lasting for 196 h showed continuous deactivation of the catalyst regarding the conversion of ethylene and propylene, whereas conversion of iso-butylene remained close to 100%. As a result, conversion of iso-butylene dominates and molecular branching increases, as indicated by the isoindex. It is shown that the catalyst can be easily reactivated by heating and catalytic performance can be fully restored.

This work investigates the impact of higher olefins and typical impurities from a preceding Dimethyl ether-to-Olefins (DtO) process on olefin oligomerization for fuel production. Feed complexity was systematically increased to mimic a DtO product containing lower and higher olefins as well as paraffinic and aromatic components. Higher olefins incorporation enhanced the yield of C13+ hydrocarbons, while impurities reduced it. Kerosene was the dominant product fraction. Temperature was determined to be the governing parameter for promoting C13+ formation and increasing diesel fuel yields, surpassing feed composition effects. Several key properties of the kerosene fraction comply with the ASTM D7566 22a standard for sustainable aviation fuels, whereas some important properties of the diesel fraction meet the ISO 8217 DMB grade for marine diesel fuel.

In order to reduce greenhouse gas emissions in road traffic, different technologies can be considered. Besides electrification, alternative fuels offer the possibility to reduce the climate impact of vehicles using combustion engines. Thereby, they can be used to reduce greenhouse gas emissions in the existing car fleet. By using biomass as raw material, biofuels offer the possibility to create a closed carbon cycle as the plants used for their production absorb CO2 from the atmosphere. In this paper, the potential to produce sustainable, biogenic gasoline with second generation biomass in Europe is evaluated. The considered potentials are only based on second generation biomass that is currently not used for other purposes. The biomass potentials include residual and waste materials, as well as perennial crops cultivated on unused marginal lands. With the considered biomass amounts, the potential gasoline that could be produced is calculated. Therefore, different pathways using ethanol and methanol as an intermediate product are considered. Besides the estimation of the mass potentials, a cost estimation as well as an outlook on future potentials is included in this study.

Oxymethylene dimethyl ethers (OMDME) have attracted interest as renewably synthesized diesel substitutes with low soot formation and NOx emissions. In order to enable a high compatibility of this new type of fuel in the already existing infrastructure, a modified oxymethylene ether (OME) synthesis based on technical alcohol mixtures, i.e., C4-based alcohol mixtures of isomers, was evaluated and the new compounds were thoroughly characterized. The synthesized compounds can be used as neat fuel or as blending component for fossil or paraffinic diesel fuels. The modification of OME offers the possibility to adjust desired properties. This versatility could also be used to synthesize compounds for the chemical sector according to its respective requirements, such as applications as solvents, plasticizers, or additives.

Methanol serves as a starting material for the production of various fuels or fuel components such as methyl tert-butyl ether (MTBE) and biodiesel. In addition, hydrocarbon fuels can be obtained either directly via Methanol-to-Gasoline (MtG) processes or indirectly via Methanol-to-Olefins (MtO) processes followed by flexible conversion of olefins to gasoline, kerosene or diesel fuel. Another option is the synthesis of dimethyl ether (DME) or oxymethylene ethers (OMEs), which exhibit properties similar to conventional diesel fuel. Within this work, the different strategies are described and compared. Provided that methanol is produced from renewable resources, e.g. by hydrogenation of CO2 in a Power-to-X (PtX) process, sustainability of methanol-based process chains can be strongly enhanced. The strategies are, at least partially, on an advanced stage of development and could significantly contribute to future mobility concepts.

Oxymethylene ethers (OMEs) are currently being investigated as attractive substitutes for fossil diesel fuel. In particular, the properties of OMEs containing 3-5 formaldehyde units (CH3O(CH2O)nCH3 with n = 3-5) are similar and mostly compliant with current diesel specifications. With their production based on renewable methanol, OMEs can contribute significantly to a future sustainable mobility. This study elaborates an anhydrous, liquid phase OME synthesis based on dimethyl ether (DME). Using a newly designed continuous production plant, the performance of extruded zeolite catalysts based on a commercially available ZSM-5 material is evaluated. The characteristics of the produced catalysts are analyzed extensively and discussed. Comprehensive characterization of the spent catalyst as well as regeneration experiments were performed to investigate catalyst deactivation mechanisms. It was shown that deactivation mechanisms are similar to those observed in methanol-to-hydrocarbon processes. Thus, understanding of these aspects is improved and approaches for further optimization can be identified.

This work explores the one-step catalytic process of erythritol hydrodeoxygenation (HDO) to 1,3-butadiene over supported Re and mixed Mo-Re oxides on carbon black. Catalyst screening under reducing H2 atmosphere was performed in liquid phase under batch conditions. Mixed Mo-Re catalysts show the best HDO performance, as they are active towards C-O scission with mild hydrogenation activity, contributing to preservation of the C--C bond of 1,3-butadiene. The effect of reaction parameters was exploited over the promising 5Mo-10Re/CB catalyst. 3-butene-1,2-diol is the main intermediate to 1,3-butadiene formed at short reaction times while longer reaction times lead to butenes. Maximum 1,3-butadiene selectivity 93 % was achieved at 51 % erythritol conversion at 140 degrees C, 60 bar and 5 h reaction time. XPS measurements of fresh and used materials indicated that the upper surface layer consists of fully and partially reduced Mo and Re species, which according to CH3OHTPSR host both redox and acid sites.

This work presents a new nine-parameter kinetic model for the synthesis of oxymethylene ethers (OME) from dimethyl ether (DME) and trioxane (TRI) on the zeolite H-ZSM-5 (Si/Al = 40), which according to recent studies is an active and selective catalyst for this reaction. To establish a database for model parametrization, experiments covering a relevant operating window were performed in a batch reactor with periodic sampling (at 353-393 K and a TRI/DME molar ratio in feed of 0.25-0.70). In addition, the database was enlarged with experiments from a previous work. The model accurately reproduced the data, and the simulations suggest that the direct incorporation of TRI to form OME3 is the preferred reaction pathway for OME production. Furthermore, an optimal operating window was identified considering the trade-off between catalyst activity and OME selectivity. Finally, a conceptual process design for continuous OME production from DME and TRI is proposed.

Within this study, the (co-)oligomerization of methanol-based olefins in the C2-4 range was investigated. The main objective was to increase the yield of oligomers with carbon chain lengths in the range of kerosene (C9-16). Commercially available mesoporous amorphous mixed silicon-aluminum oxides, optionally modified with nickel species, were applied as catalysts. Initially, single olefin feeds were employed, i.e. homo-oligomerization reactions of pure propylene and pure 1-butylene were studied at 120 degrees C and 32 bar olefin partial pressure, respectively. The co-oligomerization of olefin mixtures (C3+4 and C2+3+4), which can be obtained in Methanol-toOlefins (MtO) processes, yields product mixtures with reduced selectivities to specific chain lengths. However, selectivities to kerosene-like olefins up to 85 % have been achieved and the main side product is gasoline. Investigations with varying reaction conditions reveal comparable effects as in the case of homo-oligomerization. The use of nickel-free catalysts resulted in the highest selectivities of kerosene-like olefins, but no ethylene was converted. The negative effects of nickel catalysts on fuel quality can be compensated by two consecutive catalyst beds, the first catalyst bed with a nickel-loaded silicon-aluminum oxide for ethylene conversion followed by a catalyst bed of neat silicon-aluminum oxide for the synthesis of highly branched, long chain oligomers. The reaction network for olefin oligomerization reactions is depicted, which can be simplified remarkably in the case of catalysts without nickel. A long-term experiment lasting for more than 200 h was conducted revealing a deactivation of the acid sites of the catalysts, but also the possibility of reactivation. Selectivity to kerosene-like olefins remained above 63 % and fuel characterization showed that the resulting kerosene fraction will be suitable for blending with conventional fuels.

The influence of Pd loading on the conversion of dimethyl ether (DME) to hydrocarbons (DTH) was investigated for *MRE-type zeolite catalysts. Catalysts with different Pd loadings were prepared by incipient wetness impregnation and characterized in terms of morphology, composition and acidity. Co-feeding of H2 during DME conversion increased the resistance of the Pd/*MRE catalysts to deactivation, which significantly increased their lifetimes and thus conversion capacities. The product spectra show high olefin contents, comprising light olefins and higher olefins in the C5-C11 range, while contents of aromatics are low. H2 co-feeding reduces the formation of cyclic hydrocarbons and increases the formation of n- and iso-alkanes as well as olefins. Higher Pd loadings slightly decrease olefin production but increase paraffin formation, indicating direct hydrogenation of olefins on Pd nanoparticles. The olefin-rich products offer several possibilities for further processing to fuels and chemicals.

Direct dehydrogenation of methanol to formaldehyde and hydrogen is a "dream reaction" requiring catalysts, which are not only active in this highly endothermic reaction but also stable under harsh reaction conditions. Previous reports showed that materials with Zn2SiO4 exhibit a relatively high activity along with considerable long-time stability. However, neither detailed information on the physicochemical properties of such zinc silicates nor information on deactivation mechanisms was provided and discussed. In this study, the Zn : Si ratio has been varied to obtain different phases of zinc silicate and to investigate their specific activities in the methanol dehydrogenation reaction. Amorphous ZnO and SiO2, as well as crystalline phases of zinc oxide and zinc silicate, viz. alpha-Zn2SiO4 and beta-Zn2SiO4, were present in almost all materials in different concentrations. The beta-Zn2SiO4 phase was found to be relatively unstable in methanol dehydrogenation similar to ZnO, which is readily reduced to metallic Zn. Since detailed material characterization was not reported in studies before, the catalytic role of different phases present in zinc silicate materials for the target reaction remained unclear. Some aspects of this role are addressed within this work with a focus on alpha-Zn2SiO4 and its potential as a catalyst for direct methanol dehydrogenation.

Accurate physical property prediction of newly developed compounds is vital across various industrial sectors, particularly for the customization of fuels and additives. Artificial intelligence (AI) has recently emerged as a best practice in numerous industrial fields because of its capacity for swift and precise calculations. While conventional methods such as group contribution models have been used to estimate physical properties from molecular structure, AI offers significant potential for improving the predictive accuracy. Thus, this work focuses on developing an AI model to predict key properties - boiling points, melting points, and flashpoints - of various hydrocarbons, to demonstrate the AI's superior predictive capabilities. A dataset consisting of 202 organic compounds was created and multilayer perceptron (MLP) neural networks were employed to estimate these properties using atomic numbers, functional groups, and molecular complexity as inputs. The model's performance was evaluated and compared against conventional group contribution methods on the same dataset. The AI model was further tested on new acetal compounds, revealing its broader applicability in both fuel and chemical sectors. Results show that the AI outperformed conventional methods, excelling in 5 out of 8 hydrocarbon types for boiling points, 7 for melting points, and all 8 for flashpoints.

Sustainable hydrogen generation is preferred over production from fossil sources in the context of a carbon-neutral economy. As a result, production costs for CO2-based products are estimated to be much higher than those of their fossil equivalents. Hence, it is essential to optimize process chains regarding their hydrogen efficiency. In this study, a concept for the directly coupled production of CO2-based methanol and formaldehyde in a modified silver catalyst process is evaluated regarding the utilization of H-2. Detailed simulations in Aspen Plus allow the comparison to the separately operated synthesis of green methanol and formaldehyde. By directly connecting both production steps, utilization ratios of introduced H-2 and CO2 could be improved, reaching values of 98 % and 99 %, respectively.

Abstract Cyclohexanol and 1-methyl-1,2-cyclohexanediol were produced via the hydrotreating of guaiacol, using new hydrotalcite-based nickel (HT-Ni-R) and cobalt (HT-Co-R) catalysts.. Guaiacol is the most representative model compound for lignin-derived bio-oils. Catalysts were prepared by co-precipitation of the metals (Mg-Al, Ni or Co) followed by direct reduction with H2 at high temperature (550°C). Active species are highly dispersed Ni0 and Co0 particles formed upon reduction of part of the Ni2+ and Co2+. The main effect of the new synthesis procedure is to remarkably increase the dispersion of these metal particles, compared to those on the supported catalysts. Cobalt catalyst is more efficient for oxygen removal than the nickel catalyst, but this latter is more efficient for aromatic´s hydrogenation. HT-Ni-R produced 1-methyl-1,2-cyclohexanediol as the main product (70%). The main reaction pathway with HT-Co-R was the formation of cyclohexanol (41%). The high metal dispersion induced by the proposed synthesis procedure is the most important advantage of the new catalysts allowing the obtention of products with added value from potential renewable resources as lignin.

The production of CO2-neutral fuels is a key technology to achieve the European Union’s targets of greenhouse gas reduction in the transport sector. For a straightforward application such as drop-in fuel, regenerative gasoline must meet emission requirements without causing significant changes in engine parameters. The objective of this work was to demonstrate the emission reduction potential of fuel from the bioliq® plant by reducing the content of heavy aromatics in the product refinement. For three blends with varying contents of bioliq® fuel, the spray behavior was studied in a pressurized chamber and the particulate and hydrocarbon emissions were investigated using a single-cylinder research engine. With increasing bioliq® fuel content, atomization was degraded by lower flash boiling at low pressure. This effect vanished at higher chamber pressures. Measurements of particulate and hydrocarbon emissions showed significant improvements of 50% to 100% and 10%, respectively, compared to previously investigated bioliq® fuel fractions from 2017. The formation of particulate emissions is virtually unaffected by the blending of bioliq® fuel, due to the absence of heavy aromatics in the refined bioliq® product. Hydrocarbon emissions increased by 20% with higher bioliq® fuel content and late injection timings due to inferior mixture formation as a result of slightly reduced atomization. However, near the optimum injection timing, the hydrocarbon emissions are independent of the bioliq® fuel admixture.

The influence of the zeolite framework type on the conversion of dimethyl ether (DME) to hydrocarbons (DTH) was investigated for *MRE, MFI and TON zeolite catalysts. Remarkable differences in the catalytic performance of the materials were observed. In particular, the *MRE zeolite showed an exceptionally high yield of olefins (90%) with a substantial ratio of products in the chain length range C5-C11. Additionally, the longevity of the *MRE zeolite clearly exceeded previously reported data. The comparison of mechanistic parameters (Hydrogen-Transfer-Index HTICi and C3/C2 ratio) demonstrated for this zeolite, that the formation of aromatics in the reaction network can be almost completely suppressed under suitable reaction conditions. By varying the reaction parameters temperature, DME partial pressure and weight hourly space velocity (WHSV), it was possible to identify the optimal combination of selectivity and deactivation resistance for each material. The olefin-rich DTH product of the *MRE zeolite offers manifold possibilities for further conversion to valuable renewably produced low-emission fuels like gasoline or jet fuel.

The co-oligomerization of methanol-based C2-4 olefins on a heterogeneous nickel silica-alumina catalyst enables the production of fuel-range hydrocarbons. The objective of this study was the production of gasoline and jet fuel, which was achieved with an overall selectivity of above 90 %. The influence of olefin feed composition and pressure was investigated at 120 degrees C. By employing olefin mixtures instead of one single olefin, selectivity to specific chain lengths decreases and quantities of the individual products converge. An increase of olefin pressure from 16 to 32 bar slightly shifts the liquid products to shorter oligomers and raises feed conversion.