Thermal Rearrangement Research Articles

Analysis of Local Structure of Mechanical and Thermal Rearrangements in Glasses with the Atomic Cluster Expansion.

We explore the structural signatures of excitations in amorphous materials with the atomic cluster expansion (ACE), a universal and complete linear basis of descriptors of the atomic environment. Body-orderd linear classifiers are constructed that distinguish between active and inactive particles in three different model glass formers, in which structural relaxation occurs either through spontaneous thermal activation or by simple shear. We find that in binary mixtures, maximum prediction accuracy is already achieved with very few two-body correlations, while a polymer glass requires both two- and three-body correlations. Trends are robust across both activation mechanisms.

Mechanical, thermal and gas separation properties of copolyimides and their thermal rearrangement copolymer membranes with spirobisindane structures

In this work, two kinds of dimaine monomers with spirocyclic structures, including 3,3,3′,3′-tetramethyl-6,6′-bis[3-amino-4-hydroxyphenoxy]-1,1′-spirobisindane (TBAHS) and 3,3,3′,3′-tetramethyl-bis(5-amino-6-hydroxyphenyl)-1,1′-spirobisindane (TBHAS) are firstly synthesized. Then, the two diamines TBAHS and TBHAS are copolymerized in different molar ratios with equimolar 4,4′-(hexafluoroisopropenyl)diphthalic anhydride (6FDA) to synthesize poly(amic acid) (PAA) solution, followed by thermal imidization to obtain a series of copolyimide (coPI) membranes. Next, these coPI(TBAHS-TBHAS) specimens are subjected to thermal rearrangement (TR) treatment at 450°C to obtain the corresponding coTR(TBAHS-TBHAS) copolymer membranes. The influences of the molar ratio of TBAHS to TBHAS, thermal treatment temperature and time on the microstructures and properties of the PI and TR copolymers are investigated. With the increase of rigid TBHAS molar ratio, the glass transition temperature ( Tg) and d-spacing value of the coPI(TBAHS-TBHAS) samples are significantly enhanced. Furthermore, as the thermal treatment temperature increases, the mechanical properties of the copolymer membranes display a sharply decline trend, but the d-spacing values are obviously increased. When the molar ratio of TBAHS to TBHAS is 7:3, the gas permeabilities of the coTR membrane reach 1140.5, 1180.6, 306.6, and 44.9 Barrer for H2, CO2, O2, and N2, respectively. Meanwhile, the ideal selectivity of O2/ N2 is 6.82, suggesting a superior separation performance close to the 2015 upper limit. Furthermore, with the increase of thermal treatment temperature and time, the gas permeabilities are also improved.

Ring‐Opening Reactions of Donor‐Acceptor Cyclopropanes with Enolizable 5‐Mercapto‐1H‐tetrazoles

AbstractDiversely substituted dimethyl 2‐arylcyclopropane‐1,1‐dicarboxylates (DACD) react under mild conditions, at ambient temperature in the presence of catalytic scandium triflate, with enolizable 5‐meracaptotetrazoles. Most commonly, this yields the corresponding 1 : 1 adducts via insertion of the S‐atom into the strained C,C bond, leading to ring‐opening. Control experiments performed with dimethyl 2‐phenylcyclopropane‐1,1‐dicarboxylate and 1‐methyl‐5‐mercapto‐1H‐tetrazole demonstrated that the initial product of the reaction is the corresponding sulfane, formed via S‐insertion. However, thermal rearrangement performed at 60 °C led to the formation of the isomeric N‐insertion product. This rearrangement is accelerated by electron‐donating substituents present at the para–position of the arene. In contrast, electron‐withdrawing substituents prevent this rearrangement at room temperature, and in these examples the S‐insertion products were formed exclusively.

Voltage-induced rearrangement in silver nanoparticles spatial distribution produced by EAFD method and its LSPR optimization

Abstract This paper presents a voltage-induced and thermal annealing rearrangement (VITAR) method based on modified Electric Field Assisted Film Dissolution (EAFD) method as a flexible and powerful tool for manipulating nanoparticles spatial distribution based on drift and diffusion mechanisms that occur due to external DC voltage and thermal annealing processes. Different samples with various arrangements of external DC voltage and thermal annealing processes have been produced. The extinction and attenuated total reflection (ATR) spectra, as well as Atomic Force Microscope (AFM) images, have been employed to investigate their optical and morphological properties. Four cases with arrangements of DV-Anl, DV-Anl-DV, DV-Anl-IV, and DV-IV-Anl have been studied. The AFM images show that by applying secondary voltage (direct or inverse voltage), it is possible to drift nanoparticles and change its morphology (size and shape) as well as surface and volume distributions. As a result, by applying a secondary direct voltage (in the DV-Anl-DV case), the surface density of nanoparticles decreases due to direct drift force. It is notable that in this case, the extinction peak and ATR depth have not significantly changed. By applying a secondary inverse voltage (in the DV-Anl-IV, and DV-IV-Anl cases), an increase in the surface density of the nanoparticles has been observed. Also, the extinction peak has increased, and the ATR depth has decreased in the DV-Anl-IV case, but in the DV-IV-Anl case, due to the uniform size of surface nanoparticles, the resonance power has shown a significant increase in both extinction and ATR spectra compared to other cases. The resulting changes in extinction and ATR spectra show that by using the VITAR process, the surface structure, morphology and its optical properties can be optimized and this method provides a great opportunity to enhance Localized Surface Plasmon Resonance (LSPR) effects, which can be employed in nano-optical devices.

Synthetic Methods and Pharmacological Potentials of Isothiocyanate Derivatives

The present review deals with different synthetic methods of isothiocyanates, including alcohols, aryl chlorides, primary amines, carboxylic acid or carboxylic acid derivatives, cleavage of heterocyclic compounds, and alkene derivatives as a starting material. Furthermore, the thermal rearrangement of thiocyanate, decomposition of thiourea derivatives, and natural isothiocyanates are discussed. It also includes the chemical reaction of isothiocyanates derivatives, such as reaction with alkenes and aromatic compounds, addition of water and amine derivatives, reaction with amino alcohol derivatives, reaction with amino acids and their derivatives, reaction with hydrazine and acid hydrazide derivatives, and miscellaneous reactions. In addition, this review summarizes different pharmaceutical applications of isothiocyanate derivatives, such as anticancer, antimicrobial, antioxidant, and anti-inflammatory activities.

Boosted gas separation performances of polyimide and thermally rearranged membranes by Fe-doping

Herein, p-ferrocenylaniline (CPFEA) is first synthesized from p-nitroaniline and ferrocene as raw materials. Then, a series of Fe-doped rearrangeable polyimide (PI) membranes are prepared by polymerizing 4,4′-(hexafluoroisopropylidene)dithiocarboxylic anhydride (6FDA) and 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), with CPFEA as an end-capper, followed by thermal imidization and thermal rearrangement (TR) treatment. During the heating process, Fe2+ undergoes a valence state transition, ultimately leading to the coexistence of Fe2+ and Fe3+. The experimental results show that as the CPFEA content increases, the mechanical properties of the Fe-doped PI membranes gradually decrease, but the glass transition temperatures significantly increase due to the chelation of iron ions. In addition, owing to the synergistic effect of Fe2+/Fe3+ on thermal rearrangement reactions and intermolecular interactions, the gas permeabilities and selectivities of the TR composite membranes are greatly improved. Among them, the TR-1.0 %CPFEA sample exhibits the gas permeabilities of 2727, 2442, 407, 107, and 118 Barrer for CO2, H2, O2, N2, and CH4, and the separation performance of CO2/N2 is close to the 2008 Robeson upper limit, the CO2/CH4 exceeds the 2008 Robeson upper limit. When the thermal treatment temperature reaches 500 °C, the gas permeabilities to CO2, H2, O2, N2, and CH4 are respectively boosted to 30591, 13146, 5958, 1714, and 1882 Barrer, and the CO2/CH4 separation performance exceeds the 2019 upper limit. Therefore, this work proposes a feasible method to boost the gas separation performance by end-capping PI backbones with CPFEA, and the Fe-doped TR composite membranes are expected to play a certain role in the environmental and industrial fields.

High degree of regioselectivity during the synthesis of new allylcoumarins employing thermal Claisen rearrangement

Allyloxycoumarins (3,4) and ethyl 2-allyloxycinnamates (27, 28) were converted into 7-hydroxy-8- allylcoumarins (5,6), 2-hydroxy-3-allyl-4-methoxy-E-cinnamate ester (29), and 2-hydroxy-3-acetyl-4-methoxy-5-allyl cinnamate ester (30) by thermal Claisen rearrangement. The compounds 7-hydroxy-8-allylcoumarins (5,6) and 2-hydroxy-3- allyl cinnamate (30) on acylation or benzoylation, followed by Fries rearrangement gave 6-acetyl-7-hydroxy-8-allylcoumarins (15-20), 6-benzoyl-7-hydroxy-8-allylcoumarins (21,22), and 2-hydroxy-3-allyl-4-methoxy-5-acetylcoumarin (31). The compounds (33) and (30) underwent cyclization using boron tribromide in dichloromethane solvent at 0 degree C temperature to give 6-acetyl-7-hydroxy-8-allylcoumarin (15 or 34), that is, starting compound and 6-allyl-7-hydroxy-8-acetyl coumarin (32).. KEYWORDS :Allyl cinnamate, Coumarin, Claisen rearrangement, Regioselectivity.

Enhancing mechanical and thermal properties of blends with novel phenylethynyl-terminated siloxane-containing ortho-hydroxy polyimide

A novel phenylethynyl-terminated siloxane-containing ortho-hydroxy polyimide (O-SPI) was synthesized and physically blended with thermoplastic polyimide (PI) to enhance both the thermal and mechanical properties of polyimide, addressing the growing demand for high-performance materials in harsh environments. The blend underwent conversion to semi-Interpenetrating Polymer Networks ( semi-IPNs) and benzoxazole structures through thermal curing of reactive phenylethynyl groups and thermal rearrangement of ortho-hydroxy imide units. The trends in thermal and mechanical properties were investigated in relation to the chemical structures and varying mass fraction of O-SPI. The covalent incorporation of semi-IPNs and rigid benzoxazole structures restrict segmental motion while the backbone linkage confers the toughness of the blends. These synergistic effects insure the cured blends with high glass transition temperatures (472.51°C) and tensile strength (117.81 MPa) simultaneously, demonstrating their potential for applications in challenging conditions.

(Invited) Thermally Selective Skeletal Rearrangements at Interfaces

Thermal rearrangements, in which an atom, ion or chemical unit of a molecule is rearranged to obtain a structural isomer of the original molecule under a thermal stimulus, represents an excellent alternative to induce the formation of novel antiaromatic PCHs and conjugated polymers not accessible otherwise. Only recently, a few strain-induced rearrangement reactions of precursors that are composed of rigid and strained three dimensional (3D) structures have shown skeletal rearrangements in their backbone after planarization on metal surfaces. In this respect, the selectivity of on-surface chemical reaction pathways is a promising approach to increase synthetic versatility, though remains largely underexplored. In this talk I will review our recent discoveries regarding the exploitation of thermal rearrangements to form 0D, 1D and 2D unique molecular nanocarbons.

Thermally Rearranged (TR) Polybenzoxazoles from o-Substituted Precursor Polyimides with Phenyl Pendant Groups: Synthesis, Properties, and Thermal Rearrangement Conditions.

A series of polyimides (PIs) was synthesized from 6FDA and two o-OH substituted diamines having bulky pendant phenyl, Ph, and trifluoromethyl, CF3, groups as precursors for thermally rearranged polybenzoxazole, TR-PBO, membranes. One diamine had two pendant Ph substituents; in the other, the substituents were Ph and CF3. Applying azeotropic and chemical cyclizations allowed the obtention of four o-hydroxy (o-OH) or/and o-acetoxy (o-OAc) substituted PIs depending on the imidization method. The PIs were labeled as 3Ph-OH, 4Ph-OH, or 3Ph-OAc and 4PH-OAc, respectively. Thermal rearrangements of all four precursors were investigated in the interval from 350 to 450 °C. The conversions to TR-PBO increased with temperature, and almost quantitative conversions were obtained at temperatures close to 450 °C, although o-OH substituted PIs reached conversions slightly higher than those of o-OAc PIs at a given temperature. The TR-polymers' fractional free volume (FFV) also increased with conversion but was higher for the o-OAc substituted precursors. Despite the high TR-PBO conversions, self-supported uniform TR membranes with reasonable mechanical properties were obtained, except for 4Ph-OH. Gas separation behavior of the membranes significantly improved after the thermal treatment, and the final CO2/CH4 permselectivities lay between the 1991 and 2008 Robeson upper bounds. Particularly, TR-membranes derived from o-OAc precursors and with pendant CF3 group demonstrated better gas transport properties with values of P (CO2) = 1121 barrer and αCO2/CH4 = 29 for 3Ph-OAc derived membrane, which positioned it beyond the 2008 upper limit.

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles.

In this work, we report an efficient approach to 2-oxoazetidine-3-carboxylic acid derivatives based on a thermally promoted Wolff rearrangement of diazotetramic acids in the presence of nucleophiles. The method allows easy variation of the substituent in the exocyclic acyl group by introducing different N-, O-, and S-nucleophilic reagents into the reaction. The reaction of chiral diazotetramic acids leads exclusively to trans-diastereomeric β-lactams. The use of variously substituted diazotetramic acids, including spirocyclic derivatives, as well as a wide range of nucleophiles provides access to a structural diversity of medically relevant 2-oxoazetidine-3-carboxylic acid amides and esters.

Silylene-Stabilized Neutral Dibora-Aromatics with a B═B Bond.

The unprecedented silylene-supported dibenzodiboraoxepin 2 and 9,10-diboraphenanthrene complexes 6 and 8 were synthesized. The (NHSi)2B2(xanthene) [NHSi = PhC(NtBu)2(Me2N)Si:] 2 results from debromination of the bis(NHSi)-stabilized bis(dibromoboryl)xanthene 1 with potassium graphite (KC8); 2 is capable of activating white phosphorus and ammonia to form the B2P4 cage compound 3 and H2N-B-B-H diborane species 4, respectively. The thermal rearrangement of 2 affords the 9,10-dihydro-9,10-diboraphenanthrene 5 through a bis(NHSi)-assisted intramolecular reductive C-O-C deoxygenation process. Notably, the 9,10-diboraphenanthrene derivatives 6 and 8 could be generated by deoxygenation of 2 with KC8 and 1,3,4,5-tetramethylimidazol-2-ylidene, respectively. The aromaticity of 6 and 8 was confirmed by computational studies. Strikingly, the NHSi ligand in 8 engenders the monodeoxygenation of carbon dioxide in toluene at room temperature to form the CO-stabilized 9,10-diboraphenanthrene derivative 9 via the silaoxadiborinanone intermediate 10.

Tunable Synthesis of Pyrazolo Oxepines, Pyrazolo Thiophenes and 1H‐Indazoles Using Alkylation, Aldol Condensation and Thermal Rearrangement

AbstractBase‐mediated alkylation of 1‐alkyl/aryl‐5‐hydroxy/mercapto‐1H‐pyrazole‐4‐carbaldehydes with functionalized 3‐bromo‐prop‐1‐enes and 3‐bromo‐1‐(arylsulfonyl)propenes followed by intra‐molecular cyclization afforded regioselective pyrazolo oxepines, pyrazolo thiophenes, and 1H indazoles respectively, with good to excellent yields. This protocol paves the way for the development of syntheses of interesting biologically active scaffolds.

Microscopic Chemical Reaction Mechanism and Kinetic Model of Al/PTFE.

In order to study the microscopic reaction mechanism and kinetic model of Al/PTFE, a reactive force field (ReaxFF) was used to simulate the interface model of the Al/PTFE system with different oxide layer thicknesses (0 Å, 5 Å, 10 Å), and the thermochemical behavior of Al/PTFE at different heating rates was analyzed by simultaneous thermal analysis (TG-DSC). The results show that the thickness of the oxide layer has a significant effect on the reaction process of Al/PTFE. In the system with an oxide layer thickness of 5 Å, the compactness of the oxide layer changes due to thermal rearrangement, resulting in the diffusion of reactants (fluorine-containing substances) through the oxide layer into the Al core. The reaction mainly occurs between the oxide layer and the Al core. For the 10 Å oxide layer, the reaction only exists outside the interface of the oxide layer. With the movement of the oxygen ions in the oxide layer and the Al atoms in the Al core, the oxide layer moves to the Al core, which makes the reaction continue. By analyzing the reaction process of Al/PTFE, the mechanism function of Al/PTFE was obtained by combining the shrinkage volume model (R3 model) and the three-dimensional diffusion (D3 model). In addition, the activation energy of Al/PTFE was 258.8 kJ/mol and the pre-exponential factor was 2.495 × 1015 min-1. The research results have important theoretical significance and reference value for the in-depth understanding of the microscopic chemical reaction mechanism and the quantitative study of macroscopic energy release of Al/PTFE reactive materials.

Morphological Study before and after Thermal Treatment of Polymer-Polymer Mixed-Matrix Membranes for Gas Separations.

A good integration of the polymer materials that form a mixed-matrix membrane (MMM) for gas separation is essential to reaching interesting permselective properties. In this work, a porous polymer network (PPN), obtained by combining triptycene and trifluoroacetophenone, has been used as a filler, which was blended with two o-hydroxypolyamides (HPAs) that act as polymer matrices. These polymer matrices have been thermally treated to induce a thermal rearrangement (TR) of the HPAs to polybenzoxazoles (β-TR-PBOs) through a solid-state reaction. For its structural study, various techniques have been proposed that allow us to undertake a morphological investigation into the integration of these materials. To access the internal structure of the MMMs, three different methods were used: a polishing process for the material surface, the partial dissolution of the polymer matrix, or argon plasma etching. The argon plasma technique has not only revealed its potential to visualize the internal structure of these materials; it has also been proven to allow for the transformation of their permselective properties. Force modulation and phase contrast in lift-mode techniques, along with the topographic images obtained via the tapping mode using a scanning probe microscope (SPM), have allowed us to study the distribution of the filler particles and the interaction of the polymer and the filler. The morphological information obtained via SPM, along with that of other more commonly used techniques (SEM, TGA, DSC, FTIR, WASX, gas adsorption, and permeability measurements), has allowed us to postulate the most probable structural configuration in this type of system.

Molecular design of free volume structure in thermally rearranged polybenzoxazole membranes for gas separation studied by positron annihilation

AbstractIn this work, 2,2‐bis(3‐amino‐4‐hydroxyphenyl) hexafluoropropane (APAF) was used as the fixed diamine monomer, and 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 4,4′‐oxydiphthalic anhydride (ODPA), 3,3′,4,4′‐biphenyltetracarboxylic diandhydride (BPDA) and pyromellitic dianhydride (PMDA) were selected as four different dianhydride monomers, respectively, to prepare the thermally rearranged polybenzoxazole (TR‐PBO) gas separation membranes with different structures via a thermal rearrangement reaction at 450°C. The microstructure of TR‐PBO membranes was investigated using X‐ray diffraction and positron annihilation spectroscopy. All the TR‐PBO membranes exhibit bimodal free volume structure, containing ultramicropores (<0.7 nm) and micropores (<2 nm) with size of 3.6–4.6 and 7.6–8.4 Å, respectively. As the steric hindrance of the bridging groups in the dianhydride monomers increases, the radius and number of pores in the membranes increases, leading to an increase in fractional free volume (FFV). The pure gas permeation test shows a positive correlation between gas permeability and FFV in the TR‐PBO membranes, indicating that an increase in FFV is favorable for the diffusion of gas molecules. Particularly, the ultramicropores play a decisive role on the gas selectivity. All the TR‐PBO membranes exhibit excellent gas permeaselectivity. Among them, the H2/CH4 separation performance of APAF‐6FDA and APAF‐ODPA membranes approaches the 2008 Robeson upper bound, which is due to the high number of both micropores and ultramicropores. Our results demonstrate that the free volume structure of polymer membranes can be designed by selecting monomers with different structures and utilizing thermal rearrangement reactions, allowing for the preparation of gas separation membranes with high permeability and selectivity.

High-capacity dilithium hydroquinone cathode material for lithium-ion batteries.

Lithiated organic cathode materials show great promise for practical applications in lithium-ion batteries owing to their Li-reservoir characteristics. However, the reported lithiated organic cathode materials still suffer from strict synthesis conditions and low capacity. Here we report a thermal intermolecular rearrangement method without organic solvents to prepare dilithium hydroquinone (Li2Q), which delivers a high capacity of 323 mAh g-1 with an average discharge voltage of 2.8V. The reversible conversion between orthorhombic Li2Q and monoclinic benzoquinone during charge/discharge processes is revealed by in situ X-ray diffraction. Theoretical calculations show that the unique Li-O channels in Li2Q are beneficial for Li+ ion diffusion. In situ ultraviolet-visible spectra demonstrate that the dissolution issue of Li2Q electrodes during charge/discharge processes can be handled by separator modification, resulting in enhanced cycling stability. This work sheds light on the synthesis and battery application of high-capacity lithiated organic cathode materials.

Computer vision-based measurement of pure- and mixed-gas swelling in polymer membranes: Individual and synergistic effects of configurational free volume and thermal rearrangement

Although polymer swelling (i.e., dilation) data are crucial to assess the long-term stability of polymer membranes and correct sorption isotherms for highly sorbing penetrants, the swelling propensity of new generation membranes exhibiting configurational free volume (i.e, triptycene units) has never been investigated. To fill this gap, in this paper we study pure and mixed-gas swelling of a series of thermally rearranged polybenzoxazoles (TPBOs) and their poly(o-hydroxyimide) precursors exhibiting systematically varied amount of configurational free volume. The individual and synergistic effects of configurational free volume and thermal rearrangement on the polymer swelling propensity are presented and discussed. To do so, we use a newly developed experimental approach based on computer vision, which is capable of correcting most of the limitations of traditional methods used to measure swelling and achieve superior accuracy. We show that thermally rearranged glassy polymers exhibiting configurational free volume exhibit better swelling resistance relative to conventional polymers. The fundamental origin of this behavior resides, as explained by the dual mode theory, on the fact that the Langmuir's mode swelling propensity in thermally rearranged triptycene-based polymers is much lower than in glassy polymers exhibiting only conformational free volume. Differences between pure-gas and mixed-gas induced swelling are also highlighted and discussed. Finally, a thorough investigation of the swelling measurement uncertainty and precision is provided and discussed, including an analysis of the major factors affecting experimental uncertainty.

Rearrangement of Arylsulfamates and Sulfates to Para-Sulfonyl Anilines and Phenols.

The C(sp2)-aryl sulfonate functional group is found in bioactive molecules, but their synthesis can involve extreme temperatures (>190 °C or flash vacuum pyrolysis) and strongly acidic reaction conditions. Inspired by the 1917 Tyrer industrial process for a sulfa dye that involved an aniline N(sp2)-SO3 intermediate en route to a C(sp2)-SO3 rearranged product, we investigated tributylsulfoammonium betaine (TBSAB) as a milder N-sulfamation to C-sulfonate relay reagent. Initial investigations of a stepwise route involving TBSAB on selected anilines at room temperature enabled the isolation of N(sp2)-sulfamate. Subsequent thermal rearrangement demonstrated the intermediary of a sulfamate en route to the sulfonate; however, it was low-yielding. Investigation of the N-sulfamate to C--sulfonate mechanism through control experiments with variation at the heteroatom positions and kinetic isotope experiments (KIEH/D) confirmed the formation of a key N(sp2)-SO3 intermediate and further confirmed an intermolecular mechanism. Furthermore, compounds without an accessible nitrogen (or oxygen) lone pair did not undergo sulfamation- (or sulfation) -to-sulfonation under these conditions. A one-pot sulfamation and thermal sulfonation reaction was ultimately developed and explored on a range of aniline and heterocyclic scaffolds with high conversions, including N(sp2)-sulfamates (O(sp2)-sulfates) and C(sp2)-sulfonates, in up to 99 and 80% (and 88% for a phenolic example) isolated yield, respectively. Encouragingly, the ability to modulate the ortho-para selectivity of the products obtained was observed under thermal control. A sulfonated analog of the intravenous anesthetic propofol was isolated (88% yield), demonstrating a proof-of-concept modification of a licensed drug alongside a range of nitrogen- and sulfur-containing heterocyclic fragments used in drug discovery.

Significantly enhanced gas separation properties of membranes by debromination and thermal rearrangement simultaneously

One important challenge in advanced gas separation membranes is breaking the trade-off effect between gas permeability and selectivity. Here, we developed a method by combining the debromination and thermal rearrangement (TR) techniques together to significantly enhance the gas separation properties of the resulting membrane for the first time. First, we designed a co-polyimide (DBOH) containing both hydroxyl and bromine (50/50) groups in the ortho position of the imide group. After thermal treatment at 450 °C, the TR and debromination happened simultaneously as proved by TG-MS, FT-IR and XPS results, the resulting DBPO showed a larger d-spacing (7.03–9.71 Å), a 18-fold enhanced BET surface area, and 2-fold improved in ultra-microporosity (<7 Å) than its DBOH precursor. Hence, DBPO demonstrated not only an over 100 times improved CO2 permeability (7933 vs 76 Barrer) but also keep a high CO2/CH4 selectivity of 31, and the overall performance surpassed the latest 2019 trade-off curve. Besides, wonderful anti-plasticization and mixed-gas separation properties were also observed for DBPO, which showed a CO2 permeability of 3324 Barrer and CO2/CH4 selectivity of 14.7 even under the upstream CO2/CH4 mixed-gas pressure of 435 psi (1 psi = 6894.8 Pa), outperforming the latest 2018 CO2/CH4 mixed-gas upper limit. It showed 100 times improved CO2 permeability while maintain selectivity of DBPO is attributed to the significantly enhanced ultra-microporosity that increases the diffusion and solubility coefficient, whereas maintain their diffusion and solubility selectivity. Conclusively, the debromination coupled with TR provides a novel direction for designing advanced TR membranes.