Atm Of Air Research Articles

A general-purpose colourimetric air pressure indicator

A general-purpose air pressure colourimetric indicator is described based on a sensitive CO2 indicator, which responds to the change in partial pressure of CO2 in air. The indicator uses the pH indicator dye thymol blue (TB) and is green in ambient air (at 1 atm), bright blue under high vacuum (<0.01 atm) and bright yellow at high air pressures (>10 atm). The TB indicator is cast from an ink and its change in colour monitored mainly using digital photography coupled with colour analysis and quantitatively related to air pressure. The response of the TB indicator is initially probed using different Ar/CO2 gas mixtures at 1 atm pressure and then used to monitor: (i) sub-ambient air pressures, P, over the range 0.1−1 atm and (ii) super ambient air pressures over the range 1−14 atm. Colour analysis of all the photographic images taken in the two studies reveals a consistent data set that is readily related quantitatively to P, with a typical 50 % colour change at 1.02 ± 0.03 atm of air, i.e. or (4.2 ± 0.1)×10−4 atm of CO2. The 90 % response and recovery times of the indicator to sudden changes in pressure are fast, <1.7 min. Two possible applications of the TB indicator, in vacuum packaging and as a pressure sensitive paint in aerodynamics are demonstrated. This is the first example of a general-purpose air pressure colorimetric indicator and in particular one that can be used to monitor super-ambient air pressures up to ca. 10 atm.

Catalytic Conversion of Atmospheric CO2 into Organic Carbonates by Nickel(II) Complexes of Diazepane-Based N4 Ligands.

Activation of CO2 and conversion into value-added products is an effective option to mitigate CO2 emission. The nickel(II) complexes [Ni(L1)](ClO4)2 1, [Ni(L2)](ClO4)2 2, and [Ni(L3)(CH3CN)2](Ph4B)2 3 of diazepane-based ligands [1,4-bis[(pyridin-2-yl-methyl)]-1,4-diazepane (L1), 1,4-bis[2-(pyridin-2-yl)ethyl]-1,4-diazepane (L2), and 4-bis[2-(quinoline-2-yl)-methyl]-1,4-diazepane (L3)] have been synthesized and structurally characterized. The complexes were employed as the catalysts for the conversion of atmospheric CO2 into organic carbonates in the absence of cocatalyst at 1 atm pressure. The single-crystal X-ray structures of 1 and 2 exhibit distorted square-planar geometry with almost identical Ni-N bond distances (1.891-1.946 Å). The geometry of the complexes rearranged into octahedral in acetonitrile, which was studied by paramagnetic 1H NMR and electronic spectra. The complexes selectively captured CO2 from the atmospheric air and readily converted epoxides into cyclic carbonates without any cocatalyst. They showed a maximum yield of 25% (TON, 500) using 1 atm air, which is drastically enhanced up to 89% (TON, 1780) using 1 atm pure CO2 gas. This is the highest catalytic efficiency reported for CO2 fixation using nickel-based catalysts to date. The CO2 fixation reaction without organic substrate showed the formation of carbonate-bridged dinuclear nickel(II) complexes. They showed characteristic absorption bands around 571-612 nm and were further confirmed by electrospray ionization mass spectrometry, IR, and single-crystal X-ray structures. The molecular structure of carbonate-bridged intermediates exhibited two Ni2+-centers with distorted square pyramidal geometries for 2a and 3a but distorted octahedral and square pyramidal geometries for 1a. The CO2 fixation reactions possibly proceeded via the formation of CO2-bound nickel species.

Methods for the Environmental Stability improvement of CoS2 as Thermal Battery Cathode

The paper presented illustrates the environmental stability of CoS2 under varied conditions, and physical or chemical methods for its improvement. The results confirm: the decomposition rate of CoS2 increases with decreasing temperature, increasing water or oxygen partial pressure. Mixing with molten salt LiCl-KCl was adopted as the physical method to improve the environmental stability of CoS2, and good result was achieved, which was ascribed to the stronger ability of absorbing H2O in LiCl-KCl, and blocking the reaction of H2O and CoS2. Chemical route was also adopted, by forming a protect layer on CoS2. The protect layer was formed by using cation exchange method, with FeCl2 solution under specifically situation, and obvious improvement was observed. Fig. 1 shows the variety of decomposition rate of CoS2 with temperature in humid (pH2O~3x10-2 atm) air. Figure 1

Compilation and evaluation of gas phase diffusion coefficients of halogenated organic compounds.

Organic halogens are of great environmental and climatic concern. In this work, we have compiled their gas phase diffusivities (pressure-normalized diffusion coefficients) in a variety of bath gases experimentally measured by previous studies. It is found that diffusivities estimated using Fuller's semi-empirical method agree very well with measured values for organic halogens. In addition, we find that at a given temperature and pressure, different molecules exhibit very similar mean free paths in the same bath gas, and then propose a method to estimate mean free paths in different bath gases. For example, the pressure-normalized mean free paths are estimated to be 90, 350, 90, 80, 120 nm atm in air (and N2/O2), He, argon, CO2 and CH4, respectively, with estimated errors of around ±25%. A generic method, which requires less input parameter than Fuller's method, is proposed to calculate gas phase diffusivities. We find that gas phase diffusivities in He (and air as well) calculated using our method show fairly good agreement with those measured experimentally and estimated using Fuller's method. Our method is particularly useful for the estimation of gas phase diffusivities when the trace gas contains atoms whose diffusion volumes are not known.

The influence of sample thickness on the combustion of Al:Zr and Al-8Mg:Zr nanolaminate foils

Al:Zr and Al-8Mg:Zr nanocomposite foils do not combust completely in air because the penetration of oxygen and nitrogen into the foils can become limited as the product phases grow. The heat produced during the combustion of these foils could feasibly depend upon the volume fraction of the surface oxide layer that forms and therefore the initial foil thickness as well. To test this, Al:Zr and Al-8Mg:Zr foils of various thicknesses (9–61 µm) were fabricated by Physical Vapor Deposition and their heats of combustion were measured using bomb calorimetry in 1 atm of air. We found that combustion efficiency decreased significantly for Al:Zr foils as thickness increased, but Al-8Mg:Zr foils had a nearly constant combustion efficiency for the range of thicknesses studied. SEM-EDS measurements across the foil cross-sections showed that for Al:Zr foils, a distinct oxide layer formed on the external surfaces and there were low levels of oxygen and nitrogen toward their centers. For Al-8Mg:Zr foils though, there was minimal dependence between heat output and foil thickness, the surface oxide layer was more diffuse, and the oxygen and nitrogen contents were higher throughout the foil. We propose that the addition of magnesium improves heat generation by increasing the rates of oxygen and nitrogen diffusion and thus enabling the formation of solid solutions that are richer in oxygen and nitrogen throughout the bulk of the foils.

Experimental Research Into the Effect of Hyperbaric Exposures

Abstract Numerous research works indicate that staying in a hyperbaric environment is a stressor. We have undertaken studies using an animal model to determine the effect of hyperbaria on adrenocortical secretion and the level of adrenal ascorbic acid (a.a.a.). The research was conducted on 70 male hooded rats, which were divided into groups and subjected to hyperbaric air and oxygen at an overpressure of 1 and 3 atn, with some of the animals being additionally burdened with physical effort (swimming). It was found that short-term exposures (30 minutes) of rats to hyperbaric conditions caused a decrease in the content of a.a.a. With a prolonged (3-hour) exposure to 3 atm air the a.a.a. content returns to a normal level. A reduction in the a.a.a. content indicates the presence of stress in hyperbaric conditions in the rat, however, it does not allow to determine its intensity with the method used in the study.

Water Catalysis of the Reaction between Methanol and OH at 294 K and the Atmospheric Implications

AbstractThe rate coefficient for the reaction CH3OH+OH was determined by means of a relative method in a simulation chamber under quasi‐real atmospheric conditions (294 K, 1 atm of air) and variable humidity or water concentration. Under these conditions, a quadratic dependence of the rate coefficient for the reaction CH3OH+OH on the water concentration was found. Thus the catalytic effect of water is not only important at low temperatures, but also at room temperature. The detailed mechanism responsible of the reaction acceleration is still unknown. However, this dependence should be included in the atmospheric global models since it is expected to be important in humid regions as in the tropics. Additionally, it could explain several differences regarding the global and local atmospheric concentration of methanol in tropical areas, for which many speculations about the sinks and sources of methanol have been reported.

Water Catalysis of the Reaction between Methanol and OH at 294 K and the Atmospheric Implications.

The rate coefficient for the reaction CH3 OH+OH was determined by means of a relative method in a simulation chamber under quasi-real atmospheric conditions (294 K, 1 atm of air) and variable humidity or water concentration. Under these conditions, a quadratic dependence of the rate coefficient for the reaction CH3 OH+OH on the water concentration was found. Thus the catalytic effect of water is not only important at low temperatures, but also at room temperature. The detailed mechanism responsible of the reaction acceleration is still unknown. However, this dependence should be included in the atmospheric global models since it is expected to be important in humid regions as in the tropics. Additionally, it could explain several differences regarding the global and local atmospheric concentration of methanol in tropical areas, for which many speculations about the sinks and sources of methanol have been reported.

Sample Preparation Methodologies for In Situ Liquid and Gaseous Cell Analytical Transmission Electron Microscopy of Electropolished Specimens.

In recent years, an increasing number of studies utilizing in situ liquid and/or gaseous cell scanning/transmission electron microscopy (S/TEM) have been reported. Because of the difficulty in the preparation of suitable specimens, these environmental S/TEM studies have been generally limited to studies of nanoscale structured materials such as nanoparticles, nanowires, or sputtered thin films. In this paper, we present two methodologies which have been developed to facilitate the preparation of electron-transparent samples from conventional bulk metals and alloys for in situ liquid/gaseous cell S/TEM experiments. These methods take advantage of combining sequential electrochemical jet polishing followed by focused ion beam extraction techniques to create large electron-transparent areas for site-specific observation. As an example, we illustrate the application of this methodology for the preparation of in situ specimens from a cold-rolled Type 304 austenitic stainless steel sample, which was subsequently examined in both 1 atm of air as well as fully immersed in a H2O environment in the S/TEM followed by hyperspectral imaging. These preparation techniques can be successfully applied as a general procedure for a wide range of metals and alloys, and are suitable for a variety of in situ analytical S/TEM studies in both aqueous and gaseous environments.

Aerobic Linear Allylic C-H Amination: Overcoming Benzoquinone Inhibition.

An efficient aerobic linear allylic C-H amination reaction is reported under palladium(II)/bis-sulfoxide/Brønsted base catalysis. The reaction operates under preparative, operationally simple conditions (1 equiv of olefin, 1 atm O2 or air) with reduced Pd(II)/bis-sulfoxide catalyst loadings while providing higher turnovers and product yields than systems employing stoichiometric benzoquinone (BQ) as the terminal oxidant. Pd(II)/BQ π-acidic interactions have been invoked in various catalytic processes and are often considered beneficial in promoting reductive functionalizations. When such electrophilic activation for functionalization is not needed, however, BQ at high concentrations may compete with crucial ligand (bis-sulfoxide) binding and inhibit catalysis. Kinetic studies reveal an inverse relationship between the reaction rate and the concentration of BQ, suggesting that BQ is acting as a ligand for Pd(II) which results in an inhibitory effect on catalysis.

Graphene Oxide: A Convenient Metal-Free Carbocatalyst for Facilitating Aerobic Oxidation of 5-Hydroxymethylfurfural into 2, 5-Diformylfuran

By thermal treatment in vacuum, graphite oxide prepared by Hummer’s method was exfoliated and partially reduced. This procedure imparts to the graphene oxide (GO) high reactivity with 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) as cocatalyst for selective oxidation of 5-hydroxymethylfrufural (HMF) to 2,5-diformylfuran (DFF) under certain conditions (100% HMF conversion with HMF selectivity 99.6% at 80 wt % GO loading, 1 atm air pressure). This study found that GO could function as an oxidant for anaerobic oxidation of HMF during which carboxyl groups in GO were reduced. Importantly, the partially reduced GO material could continue to activate molecular oxygen during aerobic oxidation. Further study showed that oxygen functionalities in the GO material had a crucial effect on the catalytic oxidation of HMF. By control experiments and molecular analogues tests, a plausible mechanism was proposed in which the high reactivity was attributed to the synergistic effect of the carboxylic acid groups and unpaired ...

Design and functionality of a high-sensitivity bomb calorimeter specialized for reactive metallic foils

We have designed and built a unique non-adiabatic bomb calorimeter to measure heat generated from intermetallic formation reactions and the subsequent partial combustion of nanocomposite metallic foils. Reactions are initiated with a low-energy electrical spark and can be performed in 1 atm of air, oxygen, nitrogen, or argon, in order to investigate reaction and burning characteristics in various environments. The bomb was designed to hold the foil samples with minimal thermal contact in order to mitigate heat losses and maximize surface area available for oxidation and nitridation. Samples are limited to the milligram range, and are much less energetic than an equivalent mass of organic material such as benzoic acid. Therefore, to maximize instrument sensitivity, heat capacity was minimized by designing the bomb to be as small as possible and by using low-viscosity silicone oil for the bath instead of water. The calorimeter has an energy equivalent of e (calor) = 279 ± 6 J K−1, allowing us to measure heat generation on the order of tens of Joules. Calibrations were performed in argon using Al:Ni nanocomposite foils with well-known heats of reaction, which were measured using differential scanning calorimetry.

Electrochemical Performance of Solid Oxide Cell Oxygen Electrodes Under Pressurization

The solid oxide cell (SOC) composite oxygen electrodes (La0.8Sr0.2)0.98MnO3-δ - Zr0.84Y0.16O2-γ (LSM-YSZ) and La0.6Sr0.4Fe0.8Co0.2O3-d (LSCF) - Ce0.8Gd0.2O1.95 (LSCF-GDC) were studied at oxygen partial pressure pO2 from 0.1 to 10 atm by impedance spectroscopy. Two primary responses were observed in the impedance spectra, which were fit using an equivalent circuit model with two RQ elements. A higher frequency response observed at ~ 103 Hz varied as pO2 -0.25. A lower frequency response observed at ~ 10 to 100 Hz varied as pO2 -0.15. Total electrode resistances decreased with increasing pO2 following a pO2 -0.17 dependence for LSM-YSZ and a pO2 -0.20 dependence for LSCF-GDC. Overall, the area-specific resistance of these SOC oxygen electrodes is reduced by a factor of ~2 by increasing oxygen pressure from a nominal 0.2 atm (air) to 10 atm, thereby improving pressurized SOC performance.

Selective liquid phase oxidation of cyclohexane over Pt/CeO2-ZrO2-SnO2/SiO2 catalysts with molecular oxygen

Partial oxidation of cyclohexane into cyclohexanone and cyclohexanol (KA-oil) is an industrially significant reaction for producing precursors for the synthesis of ɛ-caprolactam and adipic acid, which are the building blocks of nylon. However, to date, the cyclohexane conversion ratio has usually been limited to less than 6% to prevent further oxidation of the cyclohexanol and cyclohexanone targets. In this study, we report that Pt/CeO2-ZrO2-SnO2/SiO2, in which CeO2-ZrO2-SnO2 provide reactive oxygen molecules from inside the bulk, can act as efficient catalysts. Optimization of the catalyst composition and reaction conditions provided a cyclohexane conversion ratio of 24.1% and a total selectivity for cyclohexanol and cyclohexanone of 83.4% at 130 °C in 0.5 MPa (4.9 atm) air for 7 h over a 5wt%Pt/16wt%Ce0.68Zr0.17Sn0.15O2.0/SiO2 catalyst. This catalyst has significant advantages over conventional catalysts because the reaction proceeds at a lower pressure, and there is no need for toxic radical initiators or free-radical scavengers.

Aerobic oxidation of cyclohexene catalyzed by NiO/MCM-41 nanocomposites in the gas phase

The nanoparticles of NiO supported on mesoporous MCM-41 were synthesized and characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this study, catalytic activities of the supported NiO nanoparticles for oxidation of cyclohexene to 2-cyclohexene-1-ol and 2-cyclohexene-1-one with air in the gas phase were considered. These nanoparticles of NiO supported on mesoporous MCM-41 were effective catalysts in a temperature range of 220–310 °C at 1 atm of air. Under these reaction conditions, the activity of the catalysts decreases in the following order: 5 wt.% NiO/MCM-41 > 7.5 wt.% NiO/MCM-41 > 2.5 wt.% NiO/MCM-41. With 5 wt.% NiO supported on mesoporous MCM-41 and under our experimental conditions, the conversion percent of cyclohexene is 62.3% with 65.9% selectivity of 2-cyclohexene-1-ol + 2-cyclohexene-1-one and 12.2% cyclohexadiene at 280 °C. To achieve higher conversion of cyclohexene and better selectivity towards 2-cyclohexene-1-ol + 2-cyclohexene-1-one, factors such as reaction temperature, loading amount of nickel oxide and space velocity were studied, and optimized conditions were investigated. The nanoparticles of NiO supported on mesoporous MCM-41 were effective catalysts of cyclohexene oxidation in a temperature range of 220–310°C under atmospheric pressure of air and under these reaction conditions, the order of catalytic activities are as follows: 5 wt.% NiO/MCM-41 > 7.5 wt.% NiO/MCM-41 > 2.5 wt.% NiO/MCM-41.

공기 중에서 망간 다이옥사이드에 의한 아민에서 이민 또는 나이트릴로의 선택적 산화 반응

염기 처리에 의한 간단한 방법으로 합성된 <TEX>$MnO_2$</TEX> (B-<TEX>$MnO_2$</TEX>)는 불균일 촉매시스템으로 호기성 조건에서 효과적인 아민 산화반응을 보여주었다. 이 B-<TEX>$MnO_2$</TEX> 촉매는 다양한 종류의 방향족, 이원자 화합물, 비활성 지방족 등의 아민의 전환에 높은 활성과 선택성을 보여주었다. 이러한 산화반응은 온화한 온도(<TEX>$50^{\circ}C$</TEX>)와 대기압의 공기 조건하에서 아민을 중간체인 이민으로 전환하고 자가 축합(self-condensation) 또는 산화적 탈수소화(oxidative dehydrogenation)을 통해 다이이민(diimine) 또는 나이트릴(nitrile)을 생성하였다. 사용된 촉매는 여과로 쉽게 분리할 수 있었고 5번 이상의 재사용 실험에서도 일정이상의 높은 수율을 보여주었다. 따라서 B-<TEX>$MnO_2$</TEX>는 아민 산화반응을 통해 이민과 나이트릴을 얻음에 있어 경제적으로나 환경친환적으로 효과적인 면을 보여 줌으로써, 그린화학(green chemistry)의 목적에 적합하다. A simple heterogeneous system has been developed by using base treated manganese dioxide (B-<TEX>$MnO_2$</TEX>) for the aerobic oxidation of amines under mild reaction conditions of 1 atm of air and <TEX>$50^{\circ}C$</TEX> in hexane. This system was highly efficient to oxidize various kinds of primary or secondary amines including aliphatic, aromatic, and hetero-atomic ones under the applied reaction conditions. Amines were oxidized to nitriles or diimines by the self-condensation or oxidative dehydrogenation through imine intermediate. The B-<TEX>$MnO_2$</TEX> was reused for at least 5 times without any loss of its catalytic performance and showed its cost effectiveness, easy workup, and easy separation of the products for achieving the protocol of green chemistry.

Kinetic Study of the OH + Glyoxal Reaction: Experimental Evidence and Quantification of Direct OH Recycling

The kinetics of the OH + glyoxal, (HCO)2, reaction have been studied in N2 and N2/O2 bath gas from 5-80 Torr total pressure and 212-295 K, by monitoring the OH decay via laser induced fluorescence (LIF) in excess (HCO)2. The following rate coefficients, kOH+(HCO)2 = (9.7 ± 1.2), (12.2 ± 1.6), and (15.4 ± 2.0) × 10(-12) cm(3) molecule(-1) s(-1) (where errors represent a combination of statistical errors at the 2σ level and estimates of systematic errors) were measured in nitrogen at temperatures of 295, 250, and 212 K, respectively. Rate coefficient measurements were observed to be independent of total pressure but decreased following the addition of O2 to the reaction cell, consistent with direct OH recycling. OH yields, ΦOH, for this reaction were quantified experimentally for the first time as a function of total pressure, temperature, and O2 concentration. The experimental results have been parametrized using a chemical scheme where a fraction of the HC(O)CO population promptly dissociates to HCO + CO, the remaining HC(O)CO either dissociates thermally or reacts with O2 to give CO2, CO, and regenerate OH. A maximum ΦOH of (0.38 ± 0.02) was observed at 212 K, independent of total pressure, suggesting that ∼60% of the HC(O)CO population promptly dissociates upon formation. Qualitatively similar behavior is observed at 250 K, with a maximum ΦOH of (0.31 ± 0.03); at 295 K, the maximum ΦOH decreased further to (0.29 ± 0.03). From the parametrization, an OH yield of ΦOH = 0.19 is calculated for 295 K and 1 atm of air. It is shown that the proposed mechanism is consistent with previous chamber studies. While the fits are robust, experimental evidence suggests that the system is influenced by chemical activation and cannot be fully described by thermal rate coefficients. The atmospheric implications of the measurements are briefly discussed.

Adsorption of cationic and anionic surfactants on natural and synthetic carbonate materials

Adsorption of cationic and anionic surfactants on carbonate materials is investigated in this study. Cetylpyridinium chloride (CPC) and sodium dodecyl sulfate (SDS) are chosen as typical cationic and anionic surfactants, respectively. It is found that the cationic CPC exhibits negligible adsorption on synthetic calcite in deionized water compared with the adsorption of the anionic SDS. However, a substantial amount of adsorption of CPC is observed on natural carbonates, such as dolomite and limestone. X-ray photoelectron spectroscopy (XPS) reveals that that a substantial amount of silicon and aluminum exists in natural dolomite and limestone but not in synthetic calcite. The adsorption plateau of CPC on carbonates highly depends on the silicon composition in the carbonate samples due to the strong electrostatic interaction between CPC and negative binding sites in silica and/or clay. The adsorption of CPC on natural carbonates is reduced in the presence of 1atm CO2 compared with the case under 1atm air, while SDS precipitates out of the solution under 1atm CO2 due to its intolerance to divalent ions released from the carbonate surface as a result of CO2 acidification.

Thermal and photochemical reactions of NO2 on chromium(iii) oxide surfaces at atmospheric pressure

While many studies of heterogeneous chemistry on Cr(2)O(3) surfaces have focused on its catalytic activity, less is known about chemistry on this surface under atmospheric conditions. We report here studies of the thermal and photochemical reactions of NO(2) on Cr(2)O(3) at one atm in air. In order to follow surface species, the interaction of 16-120 ppm NO(2) with a 15 nm Cr(2)O(3) thin film deposited on a germanium crystal was monitored in a flow system using attenuated total reflectance (ATR) coupled to a Fourier transform infrared (FTIR) spectrometer. Gas phase products were monitored in the effluent of an ~285 ppm NO(2)-air mixture that had passed over Cr(2)O(3) powder in a flow system. A chemiluminescence NO(y) analyzer, a photometric O(3) analyzer and a long-path FTIR spectrometer were used to probe the gaseous products. In the absence of added water vapor, NO(2) formed nitrate (NO(3)(-)) ions coordinated to Cr(3+). These surface coordinated NO(3)(-) were reversibly solvated by water under humid conditions. In both dry and humid cases, nitrate ions decreased during irradiation of the surface at 302 nm, and NO and NO(2) were generated in the gas phase. Under dry conditions, NO was the major gaseous product while NO(2) was the dominant species in the presence of water vapor. Heating of the surface after exposure to NO(2) led to the generation of both NO(2) and NO under dry conditions, but only NO(2) in the presence of water vapor. Elemental chromium incorporated into metal alloys such as stainless steel is readily oxidized in contact with ambient air, forming a chromium-rich metal oxide surface layer. The results of these studies suggest that active photo- and thermal chemistry will occur when boundary layer materials containing chromium(III) or chromium oxide such as stainless steel, roofs, automobile bumpers etc. are exposed to NO(2) under tropospheric conditions.

Kinetics of the gas‐phase reactions of OH radicals with a series of trimethylphenols

AbstractThe kinetics of the reactions of hydroxyl (OH) radicals with 2,3,5‐trimethylphenol (235TMP), 2,3,6‐trimethylphenol (236TMP), 2,4,5‐trimethylphenol (245TMP), 2,4,6‐trimethylphenol (246TMP), and 3,4,5‐trimethylphenol (345TMP) have been investigated at 298 ± 2 K and atmospheric pressure of air using a relative rate method. The experiments were performed in a 1080 L volume photoreactor using in situ FTIR analysis to monitor the decay of the trimethylphenols and the reference compounds. The following rate coefficients (in cm3 molecule−1 s−1) were obtained at 298 ± 2 K and 1 atm of air: k(235TMP) = (1.48 ± 0.42) × 10−10; k(236TMP) = (1.35 ± 0.39) × 10−10; k(245TMP) = (1.23 ± 0.48) × 10−10; k(246TMP) = (1.67 ± 0.48) × 10−10; k(345TMP) = (1.55 ± 0.43) × 10−10. The present kinetic data are discussed in terms of OH addition reactivity trends, and comparisons are made with the reactivity trends observed for successive methylation of benzene and phenol and successive hydroxylation of benzene. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 44: 117–124, 2012