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The chemical industry has witnessed many important developments during past decades largely enabled by process intensification techniques. Some of them are already proven at commercial scale (e.g. reactive distillation) while others (e.g. ultrasound‐assisted extraction/crystallization/reaction) are on their way to becoming the next‐generation technologies. This article focuses on the advances of ultrasound (US)‐assisted technologies that could lead in the near future to significant improvements in commercial activities. The aim is to provide an authoritative discussion on US‐assisted technologies that are currently emerging from the research environment into the chemical industry, as well as give an overview of the current state‐of‐the‐art applications of US in chemical processing (e.g. enzymatic reactive distillation, crystallization of API). Sufficient information is included to allow the assessment of US‐assisted technologies and the challenges for implementation, as well as their potential for commercial applications. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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The surface-induced melting of the close-packed (100) face of the anisotropic molecular crystal caprolactam has been studied using x-ray reflectivity. A thin-to-thick film prewetting transition is observed at about 13 K below the bulk melting point. Only above this transition does the thickness of the quasiliquid layer increase continuously with temperature. We speculate that initially the surface melting proceeds via layering transitions. PACS numbers: 64.70.Dv, 68.35.Rh, 68.45.GdThe experimental observation of a quasiliquid film wetting the solid-vapor interface below the melting temperature TM [1-5] has confirmed the old idea that the surface initiates the melting of a solid. Theoretically surface melting can be regarded as the wetting of the solid by the melt [5,6] and can result in either the quasiliquid film thickness remaining finite (incomplete wetting) or diverging (complete wetting) as the temperature approaches TM-In the latter case the divergence is governed by the range of the dominant interactions in the system. While long-range van der Waals interactions result in the thickness increasing as {TM ~ T)