02093nas a2200229 4500008004100000022001400041245011100055210006900166260000800235300001400243490000700257520131100264653002001575653001701595653001701612653001801629653001701647100002701664700002101691700002101712856013001733 2020 eng d a2585-729000aSelective monoalkylation of hydroquinone in the presence of SO3H-functionalized ionic liquids as catalysts0 aSelective monoalkylation of hydroquinone in the presence of SO3H cDEC a4461-44710 v743 a

A process aiming atO-alkylation of hydroquinone (HQ), where ionic liquids (ILs) act as catalyst is objectively described. Five SO3H-functionalized ILs having different cations were prepared and characterized by NMR and FTIR techniques. The acidity and thermal stability of ILs were determined by Hammett function and thermogravimetric analysis (TGA), respectively. The catalytic activity of these ILs were tested forO-alkylation of HQ with methanol in 4-methoxyphenol (4MP) in the presence of small amount of benzoquinone (BQ). The effect of reaction parameters such as temperature, time, catalyst loading and substrate concentration on the conversion of HQ and product distribution was examined and optimized to maximize the yield of 4MP using 1,3-disulfonic acid imidazolium hydrogen sulfate (IL2) catalyst. Maximum yield of desired product 4MP 93.79% was obtained at 338 K temperature, 5.45 x 10(-2) mol HQ, 8.33 x 10(-3) mol BQ, and 10.37 mol% catalyst loading in 120 min reaction time. Single-product formation was observed up to 338 K temperature but higher temperature (above 338 K) and longer reaction time resulted in the formation of 2,4-dimethoxyphenol (24DMP) as a by-product. Catalyst recyclability was also established up to the fifth run which showed no declination in its activity.

10a4-Methoxyphenol10aBenzoquinone10aHydroquinone10aionic liquids10aO-alkylation1 aBhongale, Priyanka, V.1 aJoshi, Sunil, S.1 aMali, Nilesh, A. uhttps://library.ncl.res.in/content/selective-monoalkylation-hydroquinone-presence-so3h-functionalized-ionic-liquids-catalysts02248nas a2200241 4500008004100000022001400041245011700055210006900172260000800241300001400249490000800263520142700271653002001698653001701718653001801735653002101753653001701774100002301791700002301814700002101837700002101858856012701879 2022 eng d a0008-403400aKinetic study on alkylation of hydroquinone with methanol over SO3H functionalized Bronsted acidic ionic liquids0 aKinetic study on alkylation of hydroquinone with methanol over S cOCT a2986-29960 v1003 a

O-alkylation of a dihydric phenol (i.e., hydroquinone) with methanol in presence of benzoquinone catalyzed by double SO3H functionalized Bronsted acidic ionic liquids (i.e., 1,3-disulphonic acid imidazolium hydrogen sulphate, 1,3-disulphonic acid benzimidazolium hydrogen sulphate, and sulphuric acid) is studied in a batch reactor. The sensitivity of activity and selectivity with reaction time, temperature, speed of agitation, and catalyst loading was examined. The plausible reaction pathways proposed based on the experimental observations and detailed kinetic investigation are performed by assuming a homogeneous reaction phase. The kinetic parameters, such as pre-exponential factor and activation energy, are estimated for both ionic liquids and sulphuric acid by considering all competitive reactions, and comparative results were presented. An extended form of the Arrhenius equation is used to estimate the kinetic parameters for the reaction which showed curvature in lnk against a 1/T plot. The model prediction with the estimated kinetic parameters is in good agreement with the experimental data, which confirmed the model validity in the experimental operating range. It was found that ionic liquid has a potential application in the synthesis of a selective monoalkylated product of hydroquinone. The kinetic analysis performed is found to be useful in the understanding of process behaviour.

10a4-Methoxyphenol10aHydroquinone10aionic liquids10aKinetic analysis10aO-alkylation1 aBhongale, Priyanka1 aAmonkar, Amogh, A.1 aJoshi, Sunil, S.1 aMali, Nilesh, A. uhttps://library.ncl.res.in/content/kinetic-study-alkylation-hydroquinone-methanol-over-so3h-functionalized-bronsted-acidic02242nas a2200217 4500008004100000022001400041245012000055210006900175260000800244300001400252490000800266520146600274653002001740653001701760653001801777653004101795100002301836700002101859700002101880856012301901 2022 eng d a1011-372X00aReusable and efficient polystyrene immobilized ionic liquid catalyst for batch and flow methylation of hydroquinone0 aReusable and efficient polystyrene immobilized ionic liquid cata cNOV a3304-33160 v1523 a

An environmentally benign process for synthesizing 4-methoxyphenol through methylation of hydroquinone using polystyrene immobilized Bronsted acidic ionic liquid is presented. The catalyst has been characterized by several techniques, such as solid-state NMR, FTIR, and XRD. The morphological properties were analyzed through SEM and TEM analysis. The elemental analysis was performed using EDS and XPS techniques. The catalyst was thermally stable up to 603 K, which was confirmed by TGA. The chemical interaction between ionic liquid and polystyrene was confirmed by measuring the glass transition temperature of pure polystyrene and catalyst. The BET analysis was performed to estimate the catalyst's surface area, pore size, and pore volume. The recyclability of the proposed new catalyst was established up to five recycle runs in the batch mode. In addition, continuous flow experiments were conducted to test the catalytic activity in terms of catalyst life span and showed excellent stability up to 20 h. The rapid separation, long-term stability, and efficient recycling of synthesized polymeric catalysts make an excellent alternative to the commonly used homogeneous catalysts for selective O-methylation of hydroquinone reaction. The newly developed continuous process for synthesizing 4-methoxyphenol with 100% selectivity suggests good opportunities to reduce energy consumption, which designates a cost-effective process. [GRAPHICS] .

10a4-Methoxyphenol10aHydroquinone10aO-methylation10aPolystyrene immobilized ionic liquid1 aBhongale, Priyanka1 aJoshi, Sunil, S.1 aMali, Nilesh, A. uhttps://library.ncl.res.in/content/reusable-and-efficient-polystyrene-immobilized-ionic-liquid-catalyst-batch-and-flow02458nas a2200229 4500008004100000022001400041245007800055210006900133260000800202300001200210490000700222520175400229653002301983653001702006653001302023653001702036653001102053100002302064700001702087700001702104856010702121 2023 eng d a0161-494000aComprehensive review on catalytic O-alkylation of phenol and hydroquinone0 aComprehensive review on catalytic Oalkylation of phenol and hydr cAPR a455-5000 v653 a

The alkylation process involves two competitive paths of O- and C-alkylation and achieving better selectivity for desired products is a very challenging problem. The development of new process for synthesis of O-methylated products of phenol and dihydric phenols is a subject of high industrial and academic interest. Alkyl phenyl ethers, especially anisole and 4-methoxyphenol, have captivated significant interest due to their increasing applications in pharmaceutical industries. The main emphasis of the present review is to explore the recent development in two catalytic O-alkylation processes. The first process is O-methylation of phenol into anisole and another is selective mono O-methylation of hydroquinone into 4-methoxyphenol. The present article covers O-alkylation methods with methanol and dimethyl carbonate as alkylating agent over various acidic and basic catalytic systems. The catalyst systems analyzed involves Bronsted and Lewis acidic and basic ionic liquids, conventional acids, metal oxides, solid acid and basic catalysts, hydrotalcites, various zeolites and heteropolyacids. The mechanistic behavior of alkylation reactions in presence of different catalytic system is reviewed critically which is important to design new and/or modified catalyst in order to maximize the yield of desired product. Additionally, an influence of reaction parameters, role of catalyst and their active sites on product distribution is described. The review paper gives useful insight for researchers in the field of catalysis and reaction engineering of alkylation reactions. Understandings of the reaction pathways will help in developing reliable kinetic models necessary for process scale-up to industrial scale reactor system.

10aDimethyl carbonate10aHydroquinone10aMethanol10aO-alkylation10aphenol1 aBhongale, Priyanka1 aJoshi, Sunil1 aMali, Nilesh uhttps://library.ncl.res.in/content/comprehensive-review-catalytic-o-alkylation-phenol-and-hydroquinone02046nas a2200205 4500008004100000022001400041245017200055210006900227260000800296300000700304490000800311520125700319653001601576653003401592653001701626653001601643100002401659700002801683856012901711 2026 eng d a0974-362600apH-Controlled electrochemical hydroxylation of acetanilide into value-added active pharmaceutical ingredients: a dual pathway synthesis of paracetamol and hydroquinone0 apHControlled electrochemical hydroxylation of acetanilide into v cMAY a760 v1383 a

A novel pH-controlled electrochemical method has been developed for the selective conversion of acetanilide into two value-added products, i.e., paracetamol and hydroquinone, via dual and tunable reaction pathways. It is shown that by adjusting the pH, and varying the electrolyte and the reaction environment specific oxidative transformations could be favored, allowing fine control over product selectivity and yield. This entire process is carried out under mild ambient conditions, eliminating the need for hazardous oxidants, specialized catalysts, or high temperatures, thereby supporting green chemistry principles. The electrochemical process also demonstrated excellent functional group tolerance, high atom economy, and minimal waste generation, highlighting its environmental and economic benefits. Its operational simplicity and scalability make it an attractive alternative to traditional multi-step methods for producing key intermediates used in drug manufacturing, fine chemicals, active pharmaceutical ingredients, and the polymer industry. This work showcases the potential of strategic electrochemical pH modulation as a powerful tool for sustainable chemical synthesis utilizing electrochemical organic transformations.

10aacetanilide10aElectrochemical hydroxylation10aHydroquinone10aparacetamol1 aBaravkar, Mayur, D.1 aPrasad, Bhagavatula, L. uhttps://library.ncl.res.in/content/ph-controlled-electrochemical-hydroxylation-acetanilide-value-added-active-pharmaceutical