The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes

Chruściel, Arkadiusz; Hreczuch, W.; Czaja, Krystyna; Ławniczak-Jabłońska, K.; Janik, J. L.

doi:10.14314/polimery.2016.421

Cited by 5 publications

(3 citation statements)

References 4 publications

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“…Four obvious steps are visible in the TG curve. The first stage is the noticeable mass loss step (∼5.6 wt %) in the 25–168 °C range, which is attributed to the liberation of water and tert -butanol molecules. ,, The second stage exhibits a sharp mass decrease (7.5%) in the 280–316 °C range probably due to decomposition of the cyanide group. ,, The following stage (316–378 °C) is most probably due to the transformation of the double-metal cyanide complexes into metal nitrates and carbonates. ,, During the fourth stage (316–586 °C), only a 1.8% mass loss was detected. For DTA, there is a small endothermic minimum connected with the first step of TG at around 100 °C.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The first stage is the noticeable mass loss step (∼5.6 wt %) in the 25−168 °C range, which is attributed to the liberation of water and tert-butanol molecules. 23,37,38 The second stage exhibits a sharp mass decrease (7.5%) in the 280−316 °C range probably due to decomposition of the cyanide group. 21,23,38 The following stage (316−378 °C) is most probably due to the transformation of the double-metal cyanide complexes into metal nitrates and carbonates.…”

Section: ■ Introductionmentioning

confidence: 99%

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Transesterification of Propylene Carbonate with Methanol Using Fe–Mn Double Metal Cyanide Catalyst

Song

Subramaniam

Chaudhari

2019

ACS Sustainable Chem. Eng.

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A highly active and selective heterogeneous catalyst consisting of Fe–Mn double metal cyanide is reported for the transesterification of cyclic carbonates with methanol. Fe–Mn double metal cyanide complex with a Fe/Mn metal ratio of 8 was found to provide significantly higher TOF and stability for transesterification of propylene carbonate with methanol to dimethyl carbonate. The experimental results showed that Mn content has a significant influence on the catalytic activity. TEM and XRD analyses suggested that Fe–Mn complex represents a cubic crystalline structure. XPS analysis showed that all Fe exists in Fe2+ state. However, for the Mn element, 86.8% of Mn exists in Mn2+ state with only 13.2% in Mn4+ state. Furthermore, FTIR and DRIFT UV–vis results verified the formation of a new mixed-metal complex of ferrocyanide moiety and Mn ions via bridging cyanide ligands. NH3-TPD results showed that Fe–Mn double metal cyanide has a strong acidity, which correlates to the high activity of Fe–Mn double metal cyanide complex. The effects of catalyst loading, methanol/PC ratio, temperature, and different cyclic carbonate substrates (ethylene carbonate, propylene carbonate, and 1,2-butylene carbonate) on the initial reaction rate as well as concentration–time profiles are reported. Unique feature of this catalyst is also nonleaching characteristics during reaction and higher TOF unlike the conventional catalysts such as CaO. Compared with the results from Fe and Mn alone as catalysts, Mn in this complex was proposed to be acting as active species, while Fe acting as a metal-dispersing agent and a stabilizer of the cyano-bridged complex and ensures a truly heterogeneous catalyst. On the basis of this, a possible reaction mechanism was proposed. The results presented in this work provide useful insights on the reaction mechanism of transesterification using Fe–Mn double metal cyanide catalysts, which may also be useful to guide rational design of improved catalysts and process for transesterification of cyclic carbonates.

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Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Transesterification of Propylene Carbonate with Methanol Using Fe–Mn Double Metal Cyanide Catalyst

Song

Subramaniam

Chaudhari

2019

ACS Sustainable Chem. Eng.

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“…10–14, the ROP of PO catalyzed by DMC can be divided into two stages: slow propagation (induction period stage) and rapid propagation. As illustrated in Scheme 1 , there are vacancies around active center Zn atom 36,37. Since only initiator ( n PPG here) and catalyst exist in the reaction system at the beginning, most of vacancies are occupied by the initiator.…”

Section: Resultsmentioning

confidence: 99%

Ring‐Opening Polymerization of Propylene Oxide by Double Metal Complex in Micro‐Reactor

Zhao

et al. 2020

Macro Reaction Engineering

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The ring‐opening polymerization of propylene oxide catalyzed by double metal complex (DMC) is carried out in continuous micro‐reactor (C‐MR). It is found that the monomer conversion at the C‐MR outlet is usually 100% within 2 min of average residence time, which means that the polymerization rate in the C‐MR is faster than that in a traditional semi‐continuous tank reactor. However, the induction period still exists in the polymerization in C‐MR, but can be shortened by increasing the reaction temperature or the micro‐reactor length. The mechanism of monomer coordination and ring opening on DMC during the induction period is confirmed by the 1H NMR analysis of the samples obtained under very short average residence time. The molecular weight distribution (MWD) of product from C‐MR is generally narrow, which indicates that the process still maintain the characteristics of the “living” polymerization. That is, there is a very high rate ratio of chain transfer to chain propagation provided by the DMC catalyst. However, with the same average residence time, the MWD of product from the longer C‐MR is broader, which can be attributed to the increase of the chain propagation rate caused by rise of pressure.

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Double Metal Cyanide (DMC) Catalysts: Synthesis, Structure, and Action Mechanism (A Review)

Pyatakov,

Nifant’ev

2023

Pet. Chem.

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The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes

Cited by 5 publications

References 4 publications

Transesterification of Propylene Carbonate with Methanol Using Fe–Mn Double Metal Cyanide Catalyst

Transesterification of Propylene Carbonate with Methanol Using Fe–Mn Double Metal Cyanide Catalyst

Ring‐Opening Polymerization of Propylene Oxide by Double Metal Complex in Micro‐Reactor

Double Metal Cyanide (DMC) Catalysts: Synthesis, Structure, and Action Mechanism (A Review)

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