The catalytic dehydrogenation of alcohols to carbonyl products is a green sustainable oxidation with no production of waste except for hydrogen, which can be an energy source. Additionally, a reusable heterogeneous catalyst is valuable from the viewpoint of process chemistry and water is a green solvent. We have accomplished the palladium on carbon (Pd/C)‐catalyzed dehydrogenation of primary alcohols to carboxylic acids in water under a mildly reduced pressure (800 hPa). The reduced pressure can be easily controlled by the vacuum controller of the rotary evaporator to remove the excess of generated hydrogen, which causes the reduction (reverse reaction) of aldehydes to alcohols (starting materials) and other undesirable side reactions. The present method is applicable to the reaction of various aliphatic and benzylic alcohols to the corresponding carboxylic acids, and the Pd/C could be reused at least 5 times.magnified image

A practical microchemical reaction system for keeping process flow at defined conditions, which is one of the key issues of industrial production, was developed. Controlled/living anionic polymerization was chosen as a test reaction because the molecular weight and molecular weight distribution of polymer products are quite sensitive to the relative flow rate of an initiator solution and that of a monomer solution. The polymerization of styrene in THF/hexane was carried out using a flow microreactor system consisting of two T-shaped micromixers and two microtube reactors using Smoothflow pumps at 0°C. Poly(styrene) with higher molecular weight such as Mn > 10000 could be synthesized using sBuLi (Mn = 14 000, M w /M n = 1.11). n-BuLi could also be used as an initiator. The continuous operation was performed for 3 h without any problems to obtain ca. 1 kg of the polymer, indicating the feasibility of continuous flow processes for controlled/living anionic polymerization on a relatively large scale. F low microreactors 1−3 have received significant research interests both from academia and industry, because they are expected to make revolutionary changes in chemical synthesis and production. The flow microreactor technology improves not only selectivity, safety, and sustainability of reactions, but also speed and efficiency of discovery and optimization of new drugs and functional materials. Moreover, another attractive feature of flow microreactor technology is that the scale-up of a reaction from laboratory synthesis to industrial production can be performed with minimun reoptimiziation of the process. Because of these advantages, the flow microreactor technology is expected to serve as a key technology for chemical and pharmaceutical industries. To accelerate the progress of this field the Micro Chemical Production Study Consortium in Kyoto University (MCPSC-KU) 4 was founded in 2009. The consortium has promoted research and development relevant to the flow microreactor technology and has disseminated industry−academia collaboration facilitating the development of next-generation chemical plants based on the technology. The members of MCPSC-KU identified that keeping process flow at defined conditions during the operation is one of the key issues of the microchemical production in industry.We chose to study controlled/living anionic polymerization as a test reaction because the molecular weight and molecular weight distribution of polymer products are quite sensitive to the relative flow rate of an initiator solution and that of a monomer solution. Also, controlled/living anionic polymerization 5,6 using flow microreactors has received significant interest from industry because it enables the production of structurely well-defined polymers such as end-functionalized polymers, block polymers, gradient polymers, graft polymers, and star polymers under easily accessible conditions because of livingness and high reactivity of the anionic polymer chain ends. 7 In contrast, the batch controlled/living anionic polymeriz...

A method for safe and scalable aerobic alcohol oxidation using 2-azaadamantan-2-ol (AZADOL), an azaadamantane-type hydroxylamine catalyst, with a NO x cocatalyst in a conventional batch reactor has been developed. The use of 2 mol % AZADOL and 10 mol % NaNO2 was determined to promote aerobic alcohol oxidation quantitatively within a reasonable time (8 h). Safety is ensured by controlling the reaction temperature below the flash point of the acetic acid solvent. The robustness of the developed method is demonstrated by the 500 g scale oxidation of diacetone fructose into Shi’s catalyst for asymmetric epoxidation.

Pressure. -The clean and first dehydrogenation of primary alcohols to carboxylic acids in the presence of a heterogeneous catalyst is presented. The catalyst is reusable at least for five reaction cycles. -(SAWAMA, Y.; MORITA, K.; ASAI, S.; KOZAWA, M.; TADOKORO, S.; NAKAJIMA, J.; MONGUCHI, Y.; SAJIKI*, H.; Adv. Synth. Catal. 357 (2015) 6, 1205-1210, http://dx.