Paired Electrolysis of Acrylonitrile and 5-Hydroxymethylfurfural for Simultaneous Generation of Adiponitrile and 2,5-Furandicarboxylic Acid

Round 1

Reviewer 1 Report

The reviewed manuscript entitled: “Paired electrolysis of acrylonitrile and 5-hydroxymethylfurfural for simultaneous generation of adiponitrile and 2,5-furandi-3 carboxylic acid” could be regarded as field-contributive research in terms of achieved electrochemical conversion efficiency of the well-chosen reagent pair – acrylonitrile and 5-hydroxymethylfurfural. However, I have a few critical and text improvement remarks as following:

The Introduction part could be further fortified by explaining that AN (electro)hydrodimerization reaction and the electrooxidized 5-hydroxymethylfurfural leading to valuable intermediate products e.g. adiponitrile and furfural dicarboxilic acid. The adiponitrile could be further hydrogenated to valuable monomer – hexamethylenediamine which could further be polymerized with the dicarboxylic acid monomer to some potentially valuable polyamide resin.. In this regard, is it possible the adiponitrile to be electrochemically hydrogenated to hexamethylenediamine in the HER?

The sentence: “The catalytic efficiency of the anode and  cathode were improved by the above two methods, respectively. In the paired electrolysis  system, when 1440 C passes through the system under constant current condition, the  anode and cathode achieved 83.7% FDCA yield and 62.3% ADN yield, respectively, while  the Faraday efficiency of the whole cell reached 107.1%.” is unclear – what is 1440C for? At first glance the overall 107.1% Faraday efficiency sounds counterintuitive though almost sure no mistake done by the authors but may be some more detailed explanation of this achieved result in particular.

Results and discussion part:

Here, the electrochemical performance of the newly synthesized multimetalic Ni catalyst is evaluated in alkaline media (dilute KOH solution). This is good but in a next real cell electrochemical transformation the authors use proton-conductive Nafion membrane and also the reaction Schemes showed H+ evaluation on the anode occur and passes true the PEM. So, probably these are acidic conditions – how this influence the Ni catalyst performance/durability? Is it possible the same to be performed in alkaline or anion-exchange or anion-conductive membrane (AEM) cell configuration? The Ni3+ ions if released in the aqueous media then is it possible a side reaction with the furfural dicarboxylic acid (corresponding salt/complex formation)? This seems undesirable process in terms of utilization/purification and so on.

The addition of water-soluble polar organic co-solvent like DMF acting as phase compatibilizer is a good approach for improving the AN water miscibility and also the DMF electrooxidation stability. But my question is what about the next step adiponitrile isolation/recovery from the water/DMF mixture as I understand by DMC extraction process – how about possible DMF contamination co-extraction occur? Have you compared with pure water mixture?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The work submitted by Qi et al has shown the heterogeneous electrolysis of acrylonitrile and 5-hydroxymethylfurfural and characterized electrode, electrochemical reaction with proper care and prepared manuscript with utmost care. However, I think, the following points should be addressed before final acceptance.    

1. In line 81, NiMoP film is reported as amorphous without referring to XRPD, provided at SI S5. It should be mentioned in the text.  

2. After electrolysis the SEM of electrode should be done, as on coated surface, cracks were there. Besides On the cathode electrode, the Ni, Mo, P elemental mapping is necessary and at the anode, Pd elemental mapping is also necessary, just to ensure that no cation is moving to the opposite electrode.

3. The products were not characterized by IR, NMR to confirm the structure.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf