Microwave assisted organic synthesis—a review (2023)

Table of Contents
Tetrahedron Introduction Section snippets Background and theory Domestic household ovens—‘solvent-free’ open vessel reactions Conclusions Acknowledgements First page preview References (603) Tetrahedron Lett. Tetrahedron Tetrahedron Lett. Tetrahedron Tetrahedron Lett. Tetrahedron Tetrahedron Lett. Tetrahedron Lett. Tetrahedron Tetrahedron Lett. Tetrahedron Lett. Bioorg. Med. Chem. Lett. Bioorg. Chem. Tetrahedron Lett. Tetrahedron Lett. Tetrahedron Lett. Mendeleev Commun. Tetrahedron Lett. Tetrahedron Lett. Tetrahedron Lett. Tetrahedron Tetrahedron Lett. Tetrahedron Tetrahedron Lett. Tetrahedron Lett. Tetrahedron Microwave Cooking and Processing Chem. Soc. Rev. Can. J. Chem. Contemp. Org. Synth. Synthesis Aust. J. Chem. Chem. Soc. Rev. J. Chem. Soc., Chem. Commun. Aust. J. Chem. Kinet. Katal. Chem. Rev. AMPERE Newslett. J. Phys. Org. Chem. J. Mater. Sci. Laboratory microwave safety Aust. J. Chem. J. Org. Chem. J. Chem. Res. J. Chem. Res. J. Chem. Res. Gazz. Chim. Ital. Synth. Commun. J. Chem. Res. Synth. Commun. Cited by (3077) Solvothermal synthesis of lanthanide-functionalized graphene oxide nanocomposites Fast microwave-assisted synthesis of iron–palladium catalysts supported on graphite for the direct synthesis of H<inf>2</inf>O<inf>2</inf> Application of imidazolium based ionic liquids grafted on microcrystalline cellulose as demulsifiers for water in crude oil (W/O) emulsions Optimized preparation, thermal characterization and microwave absorption properties of deep eutectic solvents made by choline chloride and hydrated salts of alkali earth metals Synthetic approaches to production of rhamnolipid and related glycolipids Microwave-assisted synthesis, antioxidant activity, docking simulation, and DFT analysis of different heterocyclic compounds Recommended articles (6) Correlation of hydrogen-bonding propensity and anticancer profile of tetrazole-tethered combretastatin analogues An active specification switching strategy that aids in solving nonlinear sets and improves a VNS/TA hybrid optimization methodology Microwave-assisted flow systems in the green production of fine chemicals Preface Microwave synthesis, biological screening and computational studies of pyrimidine based novel coumarin scaffolds Predicting microwave-induced relative volatility changes in binary mixtures using a novel dimensionless number FAQs Videos

Tetrahedron

Volume 57, Issue 45,

5 November 2001

, Pages 9225-9283

Author links open overlay panel, , ,

Introduction

In the electromagnetic spectrum, the microwave radiation region is located between infrared radiation and radio waves. Microwaves have wavelengths of 1mm–1m, corresponding to frequencies between 0.3 and 300GHz. Telecommunication and microwave radar equipment occupy many of the band frequencies in this region. In general, in order to avoid interference, the wavelength at which industrial and domestic microwave apparatus intended for heating operates is regulated to 12.2cm, corresponding to a frequency of 2.450 (±0.050)GHz, but other frequency allocations do exist. It has been known for a long time that microwaves can be used to heat materials. In fact, the development of microwave ovens for the heating of food has more than a 50-year history.2 In the 1970s, the construction of the microwave generator, the magnetron, was both improved and simplified. Consequently, the prices of domestic microwave ovens fell considerably, leading to them becoming a mass product. The design of the oven chamber or cavity, however, which is crucial for the heating characteristics, was not significantly improved until the end of the 1980s.

In inorganic chemistry, microwave technology has been used since the late 1970s, while it has only been implemented in organic chemistry since the mid-1980s. The development of the technology for organic chemistry has been rather slow compared, to for example, combinatorial chemistry and computational chemistry. This slow uptake of the technology has been principally attributed to its lack of controllability and reproducibility, safety aspects and a generally low degree of understanding of the basics of microwave dielectric heating. Since the mid-1990s, however, the number of publications has increased significantly (Fig. 1). The main reasons for this increase include the availability of commercial microwave equipment intended for organic chemistry and the development of the solvent-free technique, which has improved the safety aspects, but are mostly due to an increased interest in shorter reaction times.

The short reaction times and expanded reaction range that is offered by microwave assisted organic synthesis are suited to the increased demands in industry. In particular, there is a requirement in the pharmaceutical industry for a higher number of novel chemical entities to be produced, which requires chemists to employ a number of resources to reduce the time for the production of compounds. Chemistry databases, software for diversity selection, on-line chemical ordering systems, open-access and high throughput systems for analysis and high-speed, parallel and combinatorial synthesis equipment have all contributed in increasing the throughput. The common factors for these technical resources are automation and computer-aided control. They do not, however, speed up the chemistry itself. Developments in the chemistry have generally been concerned with novel highly reactive reagents in solution or on solid supports.

In general, most organic reactions have been heated using traditional heat transfer equipment such as oil baths, sand baths and heating jackets. These heating techniques are, however, rather slow and a temperature gradient can develop within the sample. In addition, local overheating can lead to product, substrate and reagent decomposition.

In contrast, in microwave dielectric heating, the microwave energy is introduced into the chemical reactor remotely and direct access by the energy source to the reaction vessel is obtained. The microwave radiation passes through the walls of the vessel and heats only the reactants and solvent, not the reaction vessel itself. If the apparatus is properly designed, the temperature increase will be uniform throughout the sample, which can lead to less by-products and/or decomposition products. In pressurized systems, it is possible to rapidly increase the temperature far above the conventional boiling point of the solvent used.

Even though the total number of publications in this area is limited, the percentage of reviews is quite high and several articles are well worth reading. Mingos et al. have given a thorough explanation of the underlying theory of microwave dielectric heating.3 Gedye4 and Langa5 have discussed the suggested ‘specific microwave effect’, Loupy et al.6 have published a number of reviews on solvent-free reactions and Strauss has reported on organic synthesis in high temperature aqueous systems.7 The last microwave organic chemistry review was published by Caddick8 in 1995. Considering the developments in the field during previous years, we believe an update is now appropriate.

Apart from compiling an update on the chemistry performed, we hope to provide the chemist who is inexperienced in the field, a basic understanding of the theory behind microwave dielectric heating. An overview of the existing synthetic methodologies, as well as an outline of the benefits and limitations connected with microwave assisted organic synthesis, are additionally presented.

Section snippets

Background and theory

If two samples containing water and dioxane, respectively, are heated in a single-mode microwave cavity at a fixed radiation power and for a fixed time the final temperature will be higher in the water sample (Fig. 2).

In order to understand why this phenomenon occurs, it is necessary to comprehend the underlying mechanisms of microwave dielectric heating. As with all electromagnetic radiation, microwave radiation can be divided into an electric field component and a magnetic field component.

Domestic household ovens—‘solvent-free’ open vessel reactions

Most of the published chemistry has been performed using domestic microwave ovens. The key reasons for using a device intended for heating food items to perform syntheses are that they are readily available and inexpensive. The use of domestic ovens might be one of the main reasons why microwave assisted organic synthesis has not increased greatly in popularity, due to factors outlined earlier (Section 2.6), and conducting syntheses in domestic microwave ovens is clearly not the intended

Conclusions

Microwave heating is very convenient to use in organic synthesis. The heating is instantaneous, very specific and there is no contact required between the energy source and the reaction vessel.

Microwave assisted organic synthesis is a technique which can be used to rapidly explore ‘chemistry space’ and increase the diversity of the compounds produced. Nowadays, it could be considered that all of the previously conventionally heated reactions could be performed using this technique. The examples

Acknowledgements

We would like to thank Professor Oliver Kappe and Dr Timothy Danks for their help with the compilation of the comprehensive reference list.

Pelle Lidström, received his PhD in radiopharmaceutical organic chemistry from Uppsala University in 1997 where he worked with the synthesis of positron emitting radiotracers for applications in positron emission tomography together with Professor Bengt Långström. He then joined Pharmacia and Upjohn where he worked both with radiopharmaceutical and medicinal chemistry. Since 1999 he has been working at Personal Chemistry as a research scientist.

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References (603)

  • R.S. Varma et al.

    Tetrahedron Lett.

    (1999)

  • B. Dayal et al.

    Bioorg. Med. Chem. Lett.

    (1995)

  • M. Kidwai et al.

    Bioorg. Chem.

    (1998)

  • A. Soriente et al.

    Tetrahedron Lett.

    (1997)

  • B. Baruah et al.

    Tetrahedron Lett.

    (1997)

  • D. Michaud et al.

    Tetrahedron Lett.

    (1997)

  • N.N. Romanova et al.

    Mendeleev Commun.

    (1998)

  • U.M. Lindström et al.

    Tetrahedron Lett.

    (1999)

  • H. Glas et al.

    Tetrahedron Lett.

    (1998)

  • S. Chatti et al.

    Tetrahedron Lett.

    (2000)

  • M. Majdoub et al.

    Tetrahedron

    (1996)

  • G.V. Salmoria et al.

    Tetrahedron Lett.

    (1998)

    (Video) Lec-08|Microwave Assisted Reaction |Green Technology and Sustainable Development |Chemical

  • A.R. Hajipour et al.

    Tetrahedron

    (1999)

  • P. de la Cruz et al.

    Tetrahedron Lett.

    (1998)

  • M. Adamczyk et al.

    Tetrahedron Lett.

    (1998)

  • J.A. Vega et al.

    Tetrahedron

    (1999)

  • C.R. Buffler

    Microwave Cooking and Processing

    (1993)

  • C. Gabriel et al.

    Chem. Soc. Rev.

    (1998)

  • R.N. Gedye et al.

    Can. J. Chem.

    (1998)

  • F. Langa et al.

    Contemp. Org. Synth.

    (1997)

  • A. Loupy et al.

    Synthesis

    (1998)

  • C.R. Strauss

    Aust. J. Chem.

    (1999)

  • S.A. Galema

    Chem. Soc. Rev.

    (1997)

  • D.R. Baghurst et al.

    J. Chem. Soc., Chem. Commun.

    (1992)

  • C.R. Strauss et al.

    Aust. J. Chem.

    (1995)

  • K.R. Seddon

    Kinet. Katal.

    (1996)

  • T. Welton

    Chem. Rev.

    (1999)

  • P. Risman

    AMPERE Newslett.

    (1992)

  • M. Pagnotta et al.

    J. Phys. Org. Chem.

    (1993)

  • J.G.P. Binner et al.

    J. Mater. Sci.

    (1995)

  • H.M. Kingston et al.

    Laboratory microwave safety

  • C.R. Strauss et al.

    Aust. J. Chem.

    (1998)

  • T. Cablewski et al.

    J. Org. Chem.

    (1994)

  • H.N. Borah et al.

    J. Chem. Res.

    (1998)

  • J.A. Seijas et al.

    J. Chem. Res.

    (1999)

  • M.S. Khajavi et al.

    J. Chem. Res.

    (1996)

  • M. Kidwai et al.

    (Video) Teaching Microwave Chemistry.

    Gazz. Chim. Ital.

    (1997)

  • A.M. Yu et al.

    Synth. Commun.

    (1999)

  • M.M. Mojtahedi et al.

    J. Chem. Res.

    (1999)

  • H. Márquez et al.

    Synth. Commun.

    (2000)

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    FAQs

    What are two advantages of microwave assisted organic synthesis? ›

    In summary, the different reports available in the scientific literature discussed in this section, showed that the main advantages of the use of microwave-assisted synthesis are the shortening of the reaction time, the improvement of the purity of the product and a better control of particle size.

    What do you mean by microwave assisted organic synthesis? ›

    Microwave-assisted organic synthesis (MAOS) is based on the efficient heat transfer achieved by dielectric heating, which, in turn, is mainly dependent on the ability of the solvent or reagent to absorb microwave energy.

    What is the microwave assisted method for synthesis? ›

    Microwave synthesis has been employed in the synthesis of nanoparticles as it combines the advantage of speed and homogeneous heating of the precursor materials. Microwave irradiation has a penetration characteristic, which makes it possible to homogeneously heat up the reaction solution.

    What is the disadvantage of microwave assisted reaction? ›

    One of the limitations of microwave scale-up technology is the restricted penetration depth of microwave irradiation into absorbing materials. This means that solvent or reagents in the centre of large reaction vessel are heated by convection and not by direct 'in core' microwave dielectric heating.

    Why is microwave-assisted extraction better? ›

    Microwave-assisted extraction (MAE) is a process of using microwave energy to heat solvents in contact with a sample in order to partition analytes from the sample matrix into the solvent. The ability to rapidly heat the sample solvent mixture is inherent to MAE and the main advantage of this technique.

    What is the impact of microwave-assisted organic chemistry on drug discovery? ›

    Microwave-assisted organic synthesis has revolutionized organic synthesis. Small molecules can be built in a fraction of the time required by classical thermal methods. As a result, this technique has rapidly gained acceptance as a valuable tool for accelerating drug discovery and development processes.

    How is microwave assisted synthesis different from conventional? ›

    The microwave-assisted synthesis methods have certain benefits, including rapid and uniform heating, no selective heating of the surface, energy savings process, higher yield and shorter preparation time, lower processing cost, small narrow particle size distribution, and high purity over other conventional approaches.

    What is an example of a microwave assisted reaction? ›

    For example, the reaction of arylboronic acid with aryl aldehydes in the presence of diethylzinc and aziridine based ligand L5 gives arylated product with up to 98% ee. The reaction time can be decreased from 1 h to 15 min by changing conventional heating to microwave irradiation.

    What is the significance of microwave synthesis? ›

    Microwave-enhanced synthesis results in faster reactions, higher yields, and increased product purity. In addition, due to the availability of high-capacity microwave apparatus, the yields of the experiments have now easily scaled up from milligrams to kilograms, without the need to alter reaction parameters.

    What is the importance of microwave heating in organic synthesis? ›

    Microwave is a convenient source of heating for organic synthesis. The heating is instantaneous and very specific. Nowadays Microwave assisted organic synthesis may consider all the previously heated reaction by this technique.

    What is the working principle of microwave synthesis? ›

    Microwave synthesizers work by exposing chemical reactions to electric fields under high pressure; this rapidly heats the molecules through motion generated either through dipolar polarization or ionic conduction. Because of the high pressure, solvents can be heated beyond their standard boiling points.

    What solvents are used in microwave assisted synthesis? ›

    Polar solvents (e.g. DMF, NMP, DMSO, methanol, ethanol, and acetic acid) work well with microwaves due to their polarity, you can be sure that the temperature will rise substantially with these solvents.

    What are the side effects of microwave radiation? ›

    Microwaves are non-ionizing radiation, so they do not have the same risks as x-rays or other types of ionizing radiation. But, microwave radiation can heat body tissues the same way it heats food. Exposure to high levels of microwaves can cause skin burns or cataracts.

    What are 3 disadvantages of using a microwave? ›

    Following are the disadvantages:

    It is not advisable to stand in front of the microwave as it is harmful while cooking. Radiation it emits is dangerous. Even plastic used in microwave cooking is dangerous as it emits Bisphenol which is also again very harmful. It is more dangerous for cooking baby food.

    What are some major advantages and disadvantages of microwave transmission? ›

    What are the advantages and disadvantages of Microwave Transmission
    AdvantagesDisadvantages
    SpeedWeather interference
    DistanceLine-of-sight requirement
    ReliabilityLimited bandwidth
    Cost-effectivenessHealth concerns
    1 more row

    How long does microwave assisted extraction take? ›

    5.1. 4 Microwave-assisted extraction and digestion (MAE)
    TechniqueAdvantages
    Microwave assisted extraction (MAE)Fast extraction (20–30 min) High sample throughput Small amount of solvent or acids (5–30 mL) Moderate amount of sample (0.5–20 g)
    3 more rows

    Which extraction method is most effective? ›

    Solvent extraction is the most widely used method. The extraction of natural products progresses through the following stages: (1) the solvent penetrates into the solid matrix; (2) the solute dissolves in the solvents; (3) the solute is diffused out of the solid matrix; (4) the extracted solutes are collected.

    What is the cost of microwave assisted extraction? ›

    Microwave- Assisted Synthesis & Extraction : Monowave 450 at Rs 2250000/piece | Sector 19 | Gurgaon | ID: 13477676330.

    What is the effect of solvent in microwave assisted synthesis? ›

    The more efficient a solvent is in coupling with the microwave energy, the faster the temperature of the reaction mixture increases. Solvents play a very important role in organic synthesis. Most reactions take place in solution, and therefore, choice of solvent can be a crucial factor in the outcome of a reaction.

    What is the importance of organic synthesis in drug discovery? ›

    Organic synthesis can contribute to the discovery of biologically active small molecules in several ways. By yielding structurally diverse small molecules having features well suited for binding macromolecules, it delivers starting points for probes or drugs.

    What is the benefits of using microwave energy source in green chemistry? ›

    The use of microwave irradiation technique is regarded as a crucial element of green chemistry because it produces clean compounds without any residual toxins. The compounds produced are very efficient as they have higher yields and better reactivity and selectivity.

    What advantages do you find for the microwave technique over conventional methods? ›

    Microwave-assisted synthesis has several advantages over conventional reactions in that the microwave allows for an increase in reaction rate, rapid reaction optimization, and rapid analogue synthesis. It also uses both less energy and solvent, and it enables difficult compound synthesis.

    What is the temperature of microwave assisted synthesis? ›

    This type of continuous flow reactor is capable of operating in a genuine high-temperature/high presssure process window (310 °C/60 bar) under MW irradiation conditions. The system can be operated in an extremely energy efficient manner, utilizing 0.6–6 kW microwave power (2.45 GHz).

    Is a home microwave suitable for organic synthesis? ›

    Unmodified home microwave units are suitable in some cases. However, simple modifications (for example, a reflux condenser) can heighten the safety factor. High-pressure chemistry should only be carried out in special reactors with a microwave oven specifically designed for this purpose.

    What are some examples of microwave radiation in everyday life? ›

    The uses of the microwave are similar to that of radio waves. They are used in communications, radio astronomy, remote sensing, radar, and of course, owing to their heating application, they are used in cooking as well.

    What are 3 uses of microwave processing in histopathology? ›

    Microwave-stimulated diffusion for fast processing of tissue: Reduced dehydrating, clearing, and impregnating times.

    Why are synthesis reactions important? ›

    Synthesis reactions involve the formation of bonds between two substances. So, you might want to think of synthesis reactions as reactions that build things in your body. Because of this fact, we see synthesis reactions are important for body growth and when we need to repair damaged tissues.

    What are the benefits of microwave reactors? ›

    Microwave reactors can be beneficial to accelerate reactions at temperatures as low as -80° C with CEM's Discover CoolMate. The CoolMate utilizes the fact that microwave energy is transferred directly to molecules in solution rather than through a vessel wall.

    What are the disadvantages of microwave heating in food processing? ›

    The major disadvantage of microwave heating is nonuniform temperature distribution resulting in hot and cold spots in foods.

    What is an example of a microwave assisted reaction in water? ›

    Following are the example of microwave assisted reaction using solvents. Hydrolysis of benzyl chloride with water in microwave oven gives 97 % yield of benzyl alcohol in 3 min. The usual hydrolysis in normal way takes about 35 min.

    Why are microwave systems preferred? ›

    The signal undergoes less attenuation and is transmitted with considerably less interference (by noise signals). Besides, microwave communication is limited as it is a line of sight communication, no transmission can occur across obstacles like mountains, etc.

    What are the basic microwave principles? ›

    The principle of microwave cooking is conversion of electromagnetic energy into thermal energy within meat. During cooking, microwave energy is absorbed by rotation of water molecules and translation of ionic components in meat; the water content and the dissolved ion content are, therefore, important factors.

    What type of reaction vessels are used in microwave reaction? ›

    Microwave reactions can be carried out in an open vessel (i.e., beaker and Erlenmeyer flask as being used in the conventional microwave) or in a closed vessel.

    What is the theory of microwave heating? ›

    Different from the conventional heating, microwave heating involves an energy conversion from the electromagnetic energy to thermal energy rather than the heat transfer. Microwave energy is delivered directly to the material through molecular interaction with the electromagnetic field.

    Does microwaves break hydrogen bonds? ›

    Microwaves are a form of low energy electromagnetic radiation. Unlike x-rays or ultraviolet light, they don't have enough energy to break chemical bonds.

    What is microwave assisted extraction of essential oils? ›

    Microwave-assisted Hydro-distillation (MAHD) combines rapid heating in the microwave field with the traditional solvent extraction. This significantly enables saving of time, so the extraction can be completed in meter of minutes 14,15 .

    Is it safe to eat microwaved food everyday? ›

    The World Health Organization (WHO) agrees, stating that despite misconceptions, microwaving food doesn't make it radioactive. And, when used correctly, the organization deems the level of radiation from microwaves far below any amount that could cause harm.

    Does your body emit electromagnetic radiation? ›

    Yes, all objects, including human bodies, emit electromagnetic radiation. The wavelength of radiation emitted depends on the temperature of the objects. Such radiation is sometimes called thermal radiation. Most of the radiation emitted by human body is in the infrared region, mainly at the wavelength of 12 micron.

    How do I know if my microwave is leaking radiation? ›

    Call the phone inside the microwave.

    If you hear no ring, your microwave is not leaking radiation. If you hear a ring, your microwave is leaking radiation, assuming the settings on your phone are correct. It's highly unlikely that your leaking microwave is a danger to your health.

    What are the most problem with microwave? ›

    Microwave does not heat

    Microwave not heating is one of the most common problems with microwave. Most popular reason behind this issue is magnetron failure. A magnetron uses high voltage to produce microwave frequency to cook food. If the microwave is turned on when it is empty, this cause the magnetron to burn out.

    Why is it not microwave safe? ›

    Anything made of or containing steel, iron, copper or other hard metals should never go in your microwave. Metal surfaces reflect microwaves, which increases the heat inside the appliance and could lead to a fire.

    Why people don't use microwave? ›

    The taste and texture of the food becomes different.

    Unlike conventional ovens or stove tops, microwave ovens do not heat your food evenly. Oftentimes, your meals becomes rubbery or sticky in texture once you heat them up. There are also instances where your food has not heated evenly, and it has hot and cold spots.

    What are 2 disadvantages of microwave? ›

    Microwaves do have some downsides. For example, they may not be as effective as other cooking methods at killing bacteria and other pathogens that may lead to food poisoning. That's because the heat tends to be lower and the cooking time much shorter. Sometimes, food heats unevenly.

    What are the advantages of microwave spectroscopy? ›

    Microwave spectroscopy is suitable for studying chemically and physically very interesting molecular systems, including weakly bound complexes, radicals, ions, and other transient species. Information on molecular structure, internal motions and intermolecular interactions are easily obtained.

    What are the advantages of microwave tissue processing? ›

    It eliminates the use of xylene from the processing and also formalin as determined by the laboratory. Microwave processing substantially shortens the time from specimen reception to diagnosis without compromising the overall quality of the histologic section.

    What is one advantage of microwave assisted dehydration? ›

    In addition to providing energy, the microwave-assisted dehydration is time-saving. This technique is quick because of penetrating electromagnetic fields within the material. It leads to volumetrically heating rather than heating from the surface of the material in standard ways.

    What is the advantages and disadvantages of microwave? ›

    There are certain advantages and disadvantages of microwave cooking. Microwaves are convenient to use, they do not burn food, they are highly economical and they heat food faster and healthier than other methods. On the flip side, you'll need to use microwave-safe vessels for cooking.

    What are 3 uses of microwave processing? ›

    This process is utilized for several purposes, such as blanching, baking and (pre)cooking, thawing and tempering, pasteurization and sterilization, rapid extraction, and drying (microwave freeze drying and microwave vacuum drying).

    What is the most important advantage of using the microwave? ›

    The greatest advantage of the microwave oven is; it is time-saving, it is convenient as we can cook food in no time and maintain the nutrient and water content of the food. Microwave oven helps in heating food without burning, as there is touch button to set the time.

    What is the main benefit of microwave heating over conventional heating in organic synthesis? ›

    Microwave-assisted synthesis has several advantages over conventional reactions in that the microwave allows for an increase in reaction rate, rapid reaction optimization, and rapid analogue synthesis. It also uses both less energy and solvent, and it enables difficult compound synthesis.

    Why is it better to sip water when dehydrated? ›

    Sipping water (or any other beverage) a little bit at a time prevents the kidneys from being “overloaded,” and so helps the body retain more H2O, Nieman says. Drinking water before or during a meal or snack is another good way to hydrate.

    Are newspapers microwave safe? ›

    Paper towels, wax paper, parchment paper, paper plates and bowls are fine in the microwave. Newspaper is not sanitary and it leaches ink into whatever you're cooking, so don't use it. Brown paper bags are never safe in the microwave because they can't withstand a lot of heat and can catch fire.

    How do you dry vegetables in the microwave? ›

    Separate the leaves from the stems and sprinkle on the paper-towel-lined tray of your microwave. Microwave on HIGH for about 1 minute.

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