Type Synthesis of Two-Degrees-of-Freedom Rotational Parallel Mechanism with Two Continuous Rotational Axes

The two-rotational-degrees-of-freedom（2R） parallel mechanism（PM） with two continuous rotational axes（CRAs） has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration,and motion control,which allows for a variety of application prospects.However,no systematic analysis on structural constraints of the 2R-PM with two CRAs has been performed,and there are only a few types of 2R-PM with two CRAs.Thus,a theory regarding the type synthesis of the 2R-PM with two CRAs is systematically established.First,combining the theories of reciprocal screw and space geometry,the spatial arrangement relationships of the constraint forces applied to the moving platform by the branches are explored,which give the 2R-PM two CRAs.The different distributions of the constraint forces in each branch are also studied.On the basis of the obtained structural constraints of branches,and considering the geometric relationships of constraint forces in each branch,the appropriate kinematic chains are constructed.Through the reasonable configuration of branch kinematic chains corresponding to every structural constraint,a series of new 2R-PMs with two CRAs are finally obtained.

Continuous, homogeneous and rapid synthesis of 4-bromo-3-methylanisole in a modular microreaction system

4-Bromo-3-methylanisole is mainly used to synthesize black fluorane dye(2-anilino-3-methyl-6-dibutylaminofluorane, ODB-2), which is one of the most important heat and pressure-sensitive dyes in the manufacture of thermal papers. Compared to the industrial heterogeneous batch process, a continuous homogeneous bromination technology in a modular microreaction system has been developed, and 4-bromo-3-methylanisole has been successfully prepared through high-selective mono-bromination of 3-methylanisole with Br2 solution in CHCl3. In optimal conditions, the content of bis-brominated byproducts can be controlled less than 0.5%,which is superior to the industrial standard with 99.5% 3-methylanisole conversion at very short residence time and mild reaction temperature.

A numerical study on heat transfer enhancement and design of a heat exchanger with porous media in continuous hydrothermal flow synthesis system

The aim of this study is to use a new configuration of porous media in a heat exchanger in continuous hydrothermal flow synthesis(CHFS)system to enhance the heat transfer and minimize the required length of the heat exchanger.For this purpose,numerous numerical simulations are performed to investigate performance of the system with porous media.First,the numerical simulation for the heat exchanger in CHFS system is validated by experimental data.Then,porous media is added to the system and six different thicknesses for the porous media are examined to obtain the optimum thickness,based on the minimum required length of the heat exchanger.Finally,by changing the flow rate and inlet temperature of the product as well as the cooling water flow rate,the minimum required length of the heat exchanger with porous media for various inlet conditions is assessed.The investigations indicate that using porous media with the proper thickness in the heat exchanger increases the cooling rate of the product by almost 40% and reduces the required length of the heat exchanger by approximately 35%.The results also illustrate that the most proper thickness of the porous media is approximately equal to 90% of the product tube's thickness.Results of this study lead to design a porous heat exchanger in CHFS system for various inlet conditions.

High-efficiency and safe synthesis of tonalid via two Friedel-Crafts reactions in continuous-flow microreactors

Tonalid,an important fragrance ingredient with widespread applicatio n,was synthesized via two FriedelCrafts reactions,which were catalyzed by AlCl_(3).The traditional tonalid production was conducted in batch stirring tank reactors,suffering from low production capacity and the safety hazard of temperature runaway.To solve these problems,the continuous-flow technologies were developed for the highefficiency and intrinsically safe synthesis of tonalid in microreactors.Catalyst AlCl_(3)was neatly homogenized in proper solvents by forming complex with reactant,which was a necessary step for the continuous synthesis in microreactors.Several reaction conditions,including reactant molar ratio,catalyst concentration,temperature,and microchannel hydrodynamic diameter,were investigated for the two Friedel-Crafts reactions in micro reactors.At optimized conditions,the yields of the two Friedel-Crafts reactions were 44.15%and 97.55%,respectively.In comparison with the batch reactors,the reaction times of these two reactions could both be reduced by nearly two thirds in microreactors at the similar yield.

Multistep continuous flow synthesis of Erlotinib

Erlotinib is an orally administered, highly effective, specific epidermal growth factor receptor tyrosine kinase inhibitor, used to treat non-small cell lung cancer and pancreatic cancer. The traditional synthetic methods for Erlotinib exhibit long reaction time and safety concern. Herein, we describe a novel five-step route for the synthesis of Erlotinib in flow. These five steps comprise etherification, nitration, reduction,addition and cyclization reactions. All steps were optimized and converted to continuous flow process,which drastically reduces the reaction time and considerably improves the process safety as well as the total yield. Enabled by five continuous flow units, Erlotinib is efficiently afforded with an E-factor of 38,an overall yield of 83%, and a total residence time of 25.1 min. Majority steps in this process have been optimized for quantitative conversion, which offers the possibility of telescoping the entire process.

A sequential continuous flow synthesis and purification process of calcium dibutyryladenosine cyclophosphate

Calcium dibutyryladenosine cyclophosphate is a widely used cardiovascular drug.The traditional batch synthesis process suffers from long reaction times,tedious operations,and unstable yields.Herein,a sequential continuous flow synthesis combined with a multistage in-line purification process of calcium dibutyryladenosine cyclophosphate was developed.The acylation reaction was completed in a continuous coil reactor at 160℃ in 20 min.And the high toxic solvent pyridine was replaced by acetonitrile.Furthermore,the multistage in-line purification process was integrated into the homemade 3D circular cyclone-type micromixer chip.Combining with the membrane phase separators,the residence time of the purification step was 30 s.The isolated yield of this sequential continuous process was 92%with 99%purity.

A safe and efficient process for the preparation of difluoromethane in continuous flow

Difluoromethane is typically produced vialiquid-phase fluorination as performed in a batch reactor.However,this process suffers from some problems,e.g.,severe corrosion of the reactor,high safety risk,and the regeneration of the catalyst.In this paper,a flow process as performed in the tubular reactor was designed.The optimum conditions for continuous synthesis of difluoromethane were obtained as follows:the reaction temperature was 100℃,the molar ratio of dichloromethane to hydrogen fluoride was 1.6:1 and the reaction time was 300 s.The operation of the cyclic process was stable for 24 h with the conversion per pass of hydrogen fluoride up to 16.2%.The unreacted raw materials were easily reused.The deactivation of the common catalyst,antimony pentachloride,was investigated by catalyst concentration curve and XPS analysis.The approach proposed in this work is proven to be safe,efficient and low amount of catalyst.

Continuous synthesis of ultra-fine fiber for wearable mechanoluminescent textile

Continuous mechanoluminescence(ML)fibers and fiber-woven textiles have the potential to serve as new wearable devices for sensors,healthcare,human-computer interfacing,and Internet of Things.Considering the demands on wearability and adaptability for the ML textiles,it is essential to realize the continuous synthesis of fiber,while maintaining a desired small diameter.Here,we develop a novel adhere-coating method to fabricate ML composite fiber,consisting of a thin polyurethane(PU)core and ZnS:Cu/polydimethylsiloxane(PDMS)shell,with the outer diameter of 120μm.By diluting PDMS to tune the thickness of liquid coating layer,droplets formation has been effectively prevented.The composite fiber exhibits a smooth surface structure and superior ML performances,including high brightness,excellent flexibility,and stability.In addition,a weft knitting textile fabricated by the continuous ML fiber can be easily delighted by manually stretching,and the ML fibers can emit visible signals upon human motion stimuli when woven into commercial cloth.Such continuous ultra-fine ML fibers are promising as wearable sensing devices for human motion detection and human-machine interactions.

Continuous-flow synthesis and crystal modification of Pigment Red 53

In this study,a continuous-flow procedure containing four steps has been developed to synthesize Pigment Red 53 and modify its crystal structure.This process avoided the problems of conveying highly insoluble reaction intermediates by removing intermediate operating steps.After optimization,the overall yield of Pigment Red 53:1 reached 97.1%in the total residence time of 80 s by this diazotizationcoupling-laking-crystal transition process.From batch to continuous flow,the purity of products increased from 97.1%to 98.2%and the median diameter of pigment particles decreased from 14μm to 1.9μm.This process achieved a similar crystal transition effect in 18 s as in batch,producingα,δandνcrystals of Pigment Red 53:2 as expected.In conclusion,this continuous-flow procedure displays advantages in both synthesis and crystal transition,indicating another potential use for industrial application.

Synthesis of Single-Walled Carbon Nanotubes by Induction Thermal Plasma

The production of high quality single-walled carbon nanotubes(SWCNTs)on a bulk scale has been an issue of considerable interest.Recently,it has been demonstrated that high quality SWCNTs can be continuously synthesized on large scale by using induction thermal plasma technology.In this process,the high energy density of the thermal plasma is employed to generate dense vapor-phase precursors for the synthesis of SWCNTs.With the current reactor system,a carbon soot product which contains approximately 40 wt%of SWCNTs can be continuously synthesized at the high production rate of~100 g/h.In this article,our recent research efforts to achieve major advances in this technology are presented.Firstly,the processing parameters involved are examined systematically in order to evaluate their individual inuences on the SWCNT synthesis.Based on these results,the appropriate operating conditions of the induction thermal plasma process for an effective synthesis of SWCNTs are discussed.A characterization study has also been performed on the SWCNTs produced under the optimum processing conditions.Finally,a mathematical model of the process currently under development is described.The model will help us to better understand the synthesis of SWCNTs in the induction plasma process.

Microreactor platform for continuous synthesis of electronic doped quantum dots

Electronic doped quantum dots(Ed-QDs),by heterovalent cations doping,have held promise for future device concepts in optoelectronic and spin-based technologies due to their broadband Stokes-shifted luminescence,enhanced electrical transport and tailored magnetic behavior.Considering their scale-up requirement and the low yielding of several current colloidal synthesis methods,a stable and efficient bulk synthesis strategy must be developed.Microreactors have long been recognized as an effective platform for producing nanomaterials and fabricating large-scale structures.Here,we chose microreactor platform for continuous synthesis of Ed-QDs in the air at low temperatures.By original reverse cation exchange reaction mechanism together with varying the kinetic conditions of microreactor platform,such as liquid flow rate,the Ag doped CdS(CdS:Ag)Ed-QDs with higher yield have been synthesized successfully due to the continuous synthesis advantages with a high degree of size selectivity.Enabled by microreactor engineering simulation,this research not only provides a new synthetic method towards scale-up production but also enables to improve chemical mass production of similar functional QDs for optical devices,bioimaging and innovative information processing applications.

Continuous synthesis for zirconium metal-organic frameworks with high quality and productivity via microdroplet flow reaction

Zirconium metal-organic frameworks（Zr-MOFs） represent the most promising candidates among MOFs for industrial utilizations owing to their high porosity and excellent stability. However, the efficient synthesis of Zr-MOFs combining with continuous production, high productivity and good product quality still remains a critical issue for practical applications. Herein, we report an efficient method of synthesizing a series of Zr-MOFs through a microdroplet flow reaction, which is more accommodate the requirements of industrial production. Four types of Zr-based MOFs with different ligands and topologies（MOF-801, MOF-804, DUT-67 and MOF-808） were produced as a pure phase of high quality crystalline with uniform morphologies. Furthermore, this series of Zr-MOFs were obtained in a continuous way and at a space-time yield（STY） highly up to 367.2 kg m-3 d-1. These MOFs exhibit the similar pore structure and thermal stability with that prepared from conventional solvothermal synthesis. CO2 sorption studies on these MOFs demonstrate that the hydroxyl groups on ligand can render MOFs with high CO2/N2 selectivity.

Combinatorial Performance Mapping of Near-NMC111 Li-ion Cathodes

A combinatorial library of twenty-three,phase pure,near-NMC111(LiNi_(0.33) Mn_(0.33)Co_(0,33)O_(2))composi-tions were synthesised and their electrochemical performance,was mapped(in lithium ion half-cells).Each of the 23 compositions was made in series,using a two-step process of 1)a rapid initial contin-uous hydrothermal precipitation,followed by 2)solid state lithiation.The 23 lithiated NMC samples were then subjected to analytical methods including electron microscopy(selected samples),Powder X-ray Diffraction and electrochemical tests in half cell Li-ion configurations versus Li metal.A sample with a Ni:Mn:Co(NMC)ratio of 39:28:33,revealed a specific capacity of 150 mA h g^(-1) at a C/20 rate,which was 63 and 43% greater capacity than NMC111 and NMC433 samples produced in this work,respectively.The sample with NMC ratio 47:25:28,showed the best capacity retention characteristics,retaining 70%of its C/20 capacity at 1C,after 40 cycles.Further analysis of all the samples by cyclic voltammetry and elec-trochemical impedance spectroscopy,allowed compositional mapping of diffusion coefficients.Overall,the mapping data revealed a gradual change of properties across compositional space,which has vali-dated our combinatorial approach and allowed identification of the optimum performing near-NMC111 cathode materials.