Synthesis by extrusion: continuous, large-scale preparation of screw speeds of 55–95 rpm and feed

  • View
    0

  • Download
    0

Embed Size (px)

Text of Synthesis by extrusion: continuous, large-scale preparation of screw speeds of 55–95 rpm and...

  • Synthesis by extrusion: continuous, large-scale preparation of MOFs using little or no solvent

    Crawford, D., Casaban, J., Haydon, R., Giri, N., McNally, T., & James, S. L. (2015). Synthesis by extrusion: continuous, large-scale preparation of MOFs using little or no solvent. Chemical Science, 6(3), 1645-1649. https://doi.org/10.1039/c4sc03217a

    Published in: Chemical Science

    Document Version: Publisher's PDF, also known as Version of record

    Queen's University Belfast - Research Portal: Link to publication record in Queen's University Belfast Research Portal

    Publisher rights Copyright 2015 The Authors

    This is an open access article published under a Creative Commons Attribution License (https://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.

    General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights.

    Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact openaccess@qub.ac.uk.

    Download date:14. Apr. 2020

    https://doi.org/10.1039/c4sc03217a https://pure.qub.ac.uk/en/publications/synthesis-by-extrusion-continuous-largescale-preparation-of-mofs-using-little-or-no-solvent(76453b8b-8392-4d91-a486-97a9789f4ab4).html

  • Chemical Science www.rsc.org/chemicalscience

    ISSN 2041-6539

    EDGE ARTICLE Stuart L. James et al. Synthesis by extrusion: continuous, large-scale preparation of MOFs using little or no solvent

    Volume 6 Number 3 March 2015 Pages 1593–2124

  • Chemical Science

    EDGE ARTICLE

    O pe

    n A

    cc es

    s A

    rt ic

    le . P

    ub lis

    he d

    on 0

    8 Ja

    nu ar

    y 20

    15 . D

    ow nl

    oa de

    d on

    2 5/

    03 /2

    01 5

    15 :5

    6: 37

    . T

    hi s

    ar tic

    le is

    li ce

    ns ed

    u nd

    er a

    C re

    at iv

    e C

    om m

    on s

    A ttr

    ib ut

    io n

    3. 0

    U np

    or te

    d L

    ic en

    ce .

    View Article Online View Journal | View Issue

    Synthesis by extr

    aSchool of Chemistry and Chemical Engineer

    Building, Stranmillis Road, Belfast, BT9 5AG bMOF Technologies Ltd, 63 University Road

    moechnologies.com cIINM, WMG, University of Warwick, Cove

    warwick.ac.uk

    † Electronic supplementary informa 10.1039/c4sc03217a

    Cite this: Chem. Sci., 2015, 6, 1645

    Received 20th October 2014 Accepted 7th January 2015

    DOI: 10.1039/c4sc03217a

    www.rsc.org/chemicalscience

    This journal is © The Royal Society of C

    usion: continuous, large-scale preparation of MOFs using little or no solvent†

    Deborah Crawford,a José Casaban,b Robert Haydon,a Nicola Giri,a Tony McNallyc

    and Stuart L. James*ab

    Grinding solid reagents under solvent-free or low-solvent conditions (mechanochemistry) is emerging as a

    general synthetic technique which is an alternative to conventional solvent-intensive methods. However, it

    is essential to find ways to scale-up this type of synthesis if its promise of cleaner manufacturing is to be

    realised. Here, we demonstrate the use of twin screw and single screw extruders for the continuous

    synthesis of various metal complexes, including Ni(salen), Ni(NCS)2(PPh3)2 as well as the commercially

    important metal organic frameworks (MOFs) Cu3(BTC)2 (HKUST-1), Zn(2-methylimidazolate)2 (ZIF-8,

    MAF-4) and Al(fumarate)(OH). Notably, Al(fumarate)(OH) has not previously been synthesised

    mechanochemically. Quantitative conversions occur to give products at kg h�1 rates which, after

    activation, exhibit surface areas and pore volumes equivalent to those of materials produced by

    conventional solvent-based methods. Some reactions can be performed either under completely

    solvent-free conditions whereas others require the addition of small amounts of solvent (typically 3–4

    mol equivalents). Continuous neat melt phase synthesis is also successfully demonstrated by both twin

    screw and single screw extrusion for ZIF-8. The latter technique provided ZIF-8 at 4 kg h�1. The space

    time yields (STYs) for these methods of up to 144 � 103 kg per m3 per day are orders of magnitude greater than STYs for other methods of making MOFs. Extrusion methods clearly enable scaling of

    mechanochemical and melt phase synthesis under solvent-free or low-solvent conditions, and may also

    be applied in synthesis more generally.

    Demonstrating the scalability of solvent-free chemical synthesis is critical in moving towards more sustainable chemical processes. Mechanochemical synthesis, which typically involves solid reagents being ground together with either no solvent or only minimal solvent, and has long been used in the context of insoluble extended inorganic materials, is now emerging as a generally effective method for molecular synthesis.1 However, most reports of molecular mechanochemical synthesis nor- mally describe the use of ball mills for reactions at less than one gram scale.1b Recently, progress has been made in scaling up molecular mechanochemical synthesis by milling, typically to some tens or occasionally hundreds of grams, by using plane- tary ball mills, attrition mills or stirred media mills,2a–d and although 50 kg scale mechanochemical synthesis of drug carrier composites has been reported to be successful by ball milling,2e

    ing, Queen's University Belfast, David Keir

    , UK. E-mail: s.james@qub.ac.uk

    , Belfast BT7 1NF, UK. E-mail: contact@

    ntry, CV4 7AL, UK. E-mail: t.mcnally@

    tion (ESI) available. See DOI:

    hemistry 2015

    the generality of ball milling for mechanochemical synthesis at large (multi-kg) scale has yet to be demonstrated.

    The term extrusion refers to a family of continuous pro- cessing techniques in which materials are forced through con- strained spaces.3 An example is twin screw extrusion (TSE) in which two co- or counter-rotating screws transport material along a barrel (in an Archimedean fashion) and subject it to shearing and compression forces due to the presence of mixing/ kneading elements incorporated into the screw design. Extru- sion is widely done on industrial scales, such as in blending polymers.3 Reactive extrusion is also known in which polymer functional groups undergo a chemical reaction during the process.3b Recently, TSE has been demonstrated for the forma- tion of organic co-crystals,4 in particular for ibuprofen–nic- otinamide,4a caffeine–oxalic acid4b and AMG-517-sorbic acid4b,c

    co-crystals under melt4a or non-melt4b conditions. However, it is still questionable whether extrusion methods can be applied to covalent chemical synthesis. For example, the breaking and formation of covalent bonds involves much greater energy than do the supramolecular interactions involved in the formation of co-crystals, and the kinetics of such reactions are oen much slower (residence times in TSE are oen only a few minutes or even seconds depending on the processing parameters applied). Also, the considerable mixing, shearing and compression forces

    Chem. Sci., 2015, 6, 1645–1649 | 1645

    http://crossmark.crossref.org/dialog/?doi=10.1039/c4sc03217a&domain=pdf&date_stamp=2015-02-14 http://creativecommons.org/licenses/by/3.0/ http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1039/c4sc03217a http://pubs.rsc.org/en/journals/journal/SC http://pubs.rsc.org/en/journals/journal/SC?issueid=SC006003

  • Fig. 2 Reaction scheme for the formation of nickel(II) complexes by twin screw extrusion (TSE).

    Chemical Science Edge Article

    O pe

    n A

    cc es

    s A

    rt ic

    le . P

    ub lis

    he d

    on 0

    8 Ja

    nu ar

    y 20

    15 . D

    ow nl

    oa de

    d on

    2 5/

    03 /2

    01 5

    15 :5

    6: 37

    . T

    hi s

    ar tic

    le is

    li ce

    ns ed

    u nd

    er a

    C re

    at iv

    e C

    om m

    on s

    A ttr

    ib ut

    io n

    3. 0

    U np

    or te

    d L

    ic en

    ce .

    View Article Online

    which can occur in TSE could render any products amorphous, which may not be desirable. Further practical challenges include inducing equivalent transport rates of solid reactants with diverse particle sizes and shapes so that correct stoichi- ometry is maintained along the barrel, in addition to the changing rheological and mechanical properties of the reaction mixture as the reaction progresses.

    We report here that, surprisingly, TSE can indeed be remarkably effective for the synthesis of a range of covalently bonded metal–organic compounds, with either no added solvent or only minimal added solvent, at kg h�1 rates (and potentially much greater rates) to give pro