Solvents - Science topic

Follow the curcuminoid extraction and analysis from turmeric...

Similar molecular structures will yield similar analysis accuracy with minimum modification...Use as template methodology.

Dear Sergei,

Determining the Flory interaction parameter is generally not the easiest task.

I warmly recommend to read the following article :

Eq. 7 in particular can prove most useful in the calculation of

You are welcome

Thanks a lot, it worked at 90 degrees@. Mohammad Reza Abbasi Dmitriy Berillo Aleena Mir

Thank you so much everyone

Dear Lynn,

I don't think that one can really dissolve a fully polymerized resin (as beads I assume?). Dissolution would mean destruction.

I guess you are interested in "something" conjugated to the surface on resin-beads or incorporated into them. Here HR-MAS is the normal NMR method (as pointed out by Sengottuvelan).

You may want to try to make a dense slurry of the beads (I'd propose in a solvent/mixture with [close to] identical density to inhibit phase-separation in the NMR tube). Dependent on the nucleus you wan't to observe you may be lucky to "see something" (see enclosed a file where we acquired 19F NMR on 50 mg's of densly packed synthesis beads in a DMSO slurry with a 19F carrying molecule conjugated. This was 32 scans in a 600 MHz cryoprobe).

You might also take a look here:

But these authors only investigated the disappearance (incorporation into the beads - making the NMR signals invisible) of the solvents in the slurry (swollen resin) to my understanding.

Melting (again I think this might be destructive) of the resin occurs at 205C...I know there are dedicated NMR probes for polymers allowing high temperature....but I do not know how high....

Good luck

Alfred

Better to use other optional solvents. Avoid foregone conclusion.

Thank you dear Kishore Kumar Sriramoju

I understand

Apart from DCM and DMF, chloroform and THF are the solvents that can be used for electrospinning of PLA.

Thank you dear Mohamadjavad Mohamadkhani

Thank you so much dear Chamuditha Benaragama

Your questions suggest you really need to contact an experienced chromatogtrapher at your school so the instrument is not damaged. It takes many years of full-time experience to learn the basics of GC-MS analysis and we can not teach the technique in a forum. Please contact a local expert to help you use the system, and plan your methods so valid data is collected and the experiments follow good chromatography principles. Now, a few comments which address your questions...

"GC-MS Grade" solvents are of very high purity usually containing far less residual materials than may be found in HPLC grade solvents. HPLC analysis (and the detectors used) have different requirements than Mass Spec systems (or even FID etc detectors). *Without additional information, for GC-MS analysis, use GC-MS grade solvents where possible (this is good advice and protects the instrument and column). BTW: Specific solvent grades are usually offered to minimize certain potentially interfering compounds (e.g. Pesticide residue grade; MS grade, less particulate, less water, lower UV abs etc ...). The REAL differences, if any, will be found when you read the actual solvent analysis specification sheet provided by the manufacturer. It is on this sheet that THEY will specify which purification procedures were used and what test results were found for the batch. Different manufacturers often have different specifications and/or different definitions of "purity" so you must COMPARE the different specifications. Depending on your specific application(s) and instrumentation, you can select the solvents which are best.

Regarding methylene chloride (HPLC or GC-MS grade) for GC-MS (I assume injection solution), well that depends on the EXACT method used (of which their are millions...). I can think of a few where it could damage the system so please speak with a professional chromatographer before moving forward.

Hello Abdullah Al Ragib Abdullah Al Ragib,

there is already a question on the solubility of PET, which you can find here:

Maybe this can help you with your problem.

I have searched the web for some possible solutions and found the following information:

Here are the references for the information I provided in my previous message:

Good luck

You may check this article (listed in RG):

10.1021/je0504360

"Solubility of Berberine Chloride in Various Solvents"

J. Chem. Eng. Data 2006, 51, 2, 642–644.

There are several methods of extracting oil from algae, but the simplest and most popular one is the oil press method1. This method is similar to the concept of the olive press. It can extract up to 75 percent of the oil from the algae being pressed1. Another method that can extract up to 95 percent of oil from algae is the hexane solvent method, which combines pressing the algae with a chemical solvent1. However, this method may have some environmental and safety issues due to the use of hexane2. A more eco-friendly and efficient method is the supercritical fluid method, which uses carbon dioxide as a solvent under high pressure and temperature to extract oil from algae2. This method can also extract other valuable compounds from algae, such as proteins and pigments2.

Some references for more information on the extraction methods for algae are:

Learn more:

1. science.howstuffworks.com2. link.springer.com3. link.springer.com4. frontiersin.org5. science.howstuffworks.com6. frontiersin.org7. doi.org

Good luck

The temperature of a vessel is controlled by using a thermostat that regulates the heat input or output of the vessel according to the desired set point1. The thermostat can be either mechanical or electronic, and can be either on-off or proportional1. An on-off thermostat switches the heat source on or off when the temperature reaches a certain threshold, while a proportional thermostat adjusts the heat output continuously based on the difference between the actual and desired temperature1.

To minimize the fluctuation and noise of the temperature control, some factors that need to be considered are2:

Some examples of vessels that require precise and stable temperature control are3:

I hope this answer helps you understand how to control the temperature of a vessel with the least fluctuation and noise. If you have any other questions, please feel free to ask me. 😊

Learn more:

1. journals.asmedigitalcollection.asme.org2. eagle.org3. imo.org4. doi.org

here are some references for my previous answer:

Good luck

you are welcome

you are welcome

For cholesterol: You have to add surfactant like Triton X-100. For e.g if you want to prepare 30 mg/ml stock solution, then add 60 mg of cholesterol to 1 ml of Triton X-100 and stir it under heating at ~ 90-95 deg C until the solution become transparent. Then add 1 ml of IPA, allow it to stir for 2 min, bring to room temperature. You can store it in 4 deg C and prepare the dilutions in whichever solvent you want when DI water.

For triglycerides: If you are using triolein, mix it first with Triton X-100 and then with Tris-HCl buffer. heating is not needed. This solution will be milky but homogeneous. Prepare the dilutions in water or PBS whichever solvent is needed.

Hope this helps

How can I calculate volume of evaporated steam in a reactor?

Please enter this question in ChatGPT

It's nice

It's Polyethylene oxide

Dmitry Bagrov Try spinning the substrate and diluting the nitrocellulose.

Try with Schrodinger Q/A

The situation you describe is extremely unusual. It happens when the oil sample is polymerized (old essential oil samples; essential oils kept without protection from light and/or oxygen). Do a steam-water distillation of your essential oil sample. If you do not recover the oil means that your sample is partially or completely polymerized.

This is very much critical question, i think about it.

Stirring affects the rate of dissolving because it spreads the solvent's molecules around the solute and increases the chance of them coming into contact with each other faster. As a result, mechanical stirring increases solubility of the solute in the solvent. Stirring the solution will increase the solubility of the solution. This happens because stirring allows the solute molecules to always be in contact with the solvent molecules. Stirring a solute into a solvent speeds up the rate of dissolving because it helps distribute the solute particles throughout the solvent. As add sugar to iced tea and then stir the tea, the sugar will dissolve faster. An increase in pressure and an increase in temperature in this reaction results in greater solubility. An increase in pressure results in more gas particles entering the liquid in order to decrease the partial pressure. Therefore, the solubility would increase. An increase in temperature puts a stress on the equilibrium condition and causes it to shift to the right. The stress is relieved because the dissolving process consumes some of the heat. Therefore, the solubility (concentration) increases with an increase in temperature. Increasing the temperature will therefore increase the solubility of the solute. An example of a solute whose solubility increases with greater temperature is ammonium nitrate, which can be used in first-aid cold packs. Ammonium nitrate dissolving in solution is an endothermic reaction. Differences in temperature or concentration are balanced more efficiently during stirring. Additionally, the stirring of liquids speeds up the dissolution process and increases the speed of chemical reactions. The stirring allows fresh solvent molecules to continually be in contact with the solute. If it is not stirred, then the water right at the surface of the solute becomes saturated with dissolved sugar molecules, meaning that it is more difficult for additional solute to dissolve. Solubility is the maximum amount of a substance that will dissolve in a given amount of solvent at a specific temperature. There are two direct factors that affect solubility: temperature and pressure. Temperature affects the solubility of both solids and gases, but pressure only affects the solubility of gases. Stirring keeps reactant particles in motion increasing the chances of collision and increasing the rate of reaction.

Yes, it is.

Even with molecular sieve storage you could be disappointed in the water peak amplitude.

It turns out NMR tube glass traps H2O via interstitial bonding sites. Neither heat nor molecular sieves remove this source of H2O. In H-1 measurements for extremely dilute samples, the water peak is still a nuisance.

The solution is to soak NMR tubes in D20 overnight and store those tubes in a sealed container with a small beaker full of D20. Eventually almost all of the interstitial H2O becomes D2O. Now when the interstitial water is released into a deuterated solvent, the HDO residual peak is much less annoying..

Try to mix the pectin thoroughly with a few drops of ethanol. When the ethanol has wetted the pectin, you can add water to dissolve it and make your desired solution.

May I suggest that you clarify what you want to dope and for what purpose

@ Niti Sharma Thank you very much. It is really helpful.

Okay dear Mustafa Çom

Thank you so much for answering

Heating up a solvent gives the molecules more kinetic energy. The increased rapid motion means that the solvent molecules collide with the solute with greater frequency, and that the collisions occur with more force. Both factors increase the rate at which the solute dissolves. A solute dissolves faster in a warmer solvent than it does in a cooler solvent because particles have more energy of movement. The temperature of the solvent is another factor that affects how fast a solute dissolves. For a given amount of solute, smaller particles have greater surface area. If we heat the solvent, the average kinetic energies of its molecules increase. Hence, the solvent is able to dislodge more particles from the surface of the solute. Thus, increasing the temperature increases the solubility of substances. As the temperature of the solution increase, the average kinetic energy of the solute molecules also increases. This causes the molecules to be less able to hold together and hence they dissolve more readily. Hence increase in temperature increases the solubility of solid states. Energy will be transferred from the warmer object to the cooler one. The movement of thermal energy from a substance at a higher temperature to one at a lower temperature is called heat. When a substance is heated, it gains thermal energy. Therefore, its particles move faster and its temperature rises. Substances can change between the states of matter by adding or removing heat, also known as the transfer of thermal energy. Adding thermal energy causes a substance's particles to move faster and farther apart; removing thermal energy causes a substance's particles to move slower and closer together. Water, as well as other matter, can exist in three states, or phases, and we call them solid, liquid, and gas. As ice is heated, its temperature increases, and it melts into liquid water. Likewise, as liquid water is heated, it evaporates into water vapor. The solubility of gases is directly proportional to pressure. That is it increases with increase in pressure. The solubility of gases in liquids decreases with increasing temperature. Conversely, adding heat to the solution provides thermal energy that overcomes the attractive forces between the gas and the solvent molecules, thereby decreasing the solubility of the gas. Rises in temperature improve the solubility of solids in water, but reduce the solubility of gases in water because temperature increases produce an increase in the number of stimulated atoms or molecules of gases. Changes in pressure have essentially no effect on the solubility of solids and liquids. As the temperature of the solution increase, the average kinetic energy of the solute molecules also increases. This causes the molecules to be less able to hold together and hence they dissolve more readily. The solubility of most substances depends strongly on the temperature and, in the case of gases, on the pressure. The solubility of most solid or liquid solutes increases with increasing temperature.

Dear Aynaz Biuky

In your application, these two solvents are likely blended in specific ratios to create a mixture that can effectively dissolve and separate polymer pigments from recycled plastics and LDP (Low-Density Polyethylene). The choice of solvents may depend on their solvency properties, boiling points, and compatibility with the materials you are working with.

The process you described involves introducing this solvent mixture into a reactor at an elevated temperature (110°C). Due to the high temperature, some of the solvent evaporates, which can lead to a decrease in the reactor's temperature (to 98°C). This change in temperature is likely due to the endothermic nature of the solvent evaporation process, where heat is absorbed during vaporization.

The amount of condensate collected at different times provides valuable data for monitoring and controlling the process. It allows you to quantify the amount of solvent lost through evaporation and potentially recycle or replenish it as needed to maintain the desired solvent concentration in the reactor.

Overall, the formulation of your evaporated solvent involves blending Ethylcyclopentane and 2-Methylheptane to create a solvent mixture suitable for your polymer pigment separation and dissolution application. The process is carefully controlled to optimize solvent usage and separation efficiency.

n-methylpyrrolidone and pyrrolidone derivatives in general usually are suitable dissolving PU

Go for energy balance eqn. along with mass balance,

mH = m1H1+ m2H2 m = mass of entering stream

m1 = mass of evaporated stream

m2 = mass left in vessel

m = m1+m2

mH = m1H1 + (m-m1)H2 where H is Enthalpy for respective stream

after calculating mass you can convert its to volume by density or by using ideal gas equation for evaporated vapour.

Hi Dr., I like your question, and I would love to answer and support you on your research, but I would appreciate it if you could click RECOMMEND for my 6 research papers under my AUTHORSHIP below is my short answer to your question. Click the RECOMMEND word under each of my research papers and follow me. In return for your kind support, I provide you with the answer to your question :

Reductive cleavage of the chromophore under mild conditions would seem the most prudent preliminary synthetic step. The electrophilic reactivity of unprotected thiol moieties at elevated temperature risks engendering non-specific reactions and diminished atom economy.

Phosphorus-based reductants such as (VA-044) furnish the requisite reducing potential under ambient conditions, thus circumventing such issues. Subsequent protection of the resultant thiol moieties, via transient acetal or α-methoxymethyl ethers for example, would insulate their nucleophilic character during downstream processing.

While the elevated temperatures proposed for your aminolysis are conducive to facilitating nucleophile-electrophile conjugate addition, prolonged duration risks isomerization or decomposition pathways. A systematic kinetic study, evaluating conversion as a function of time, would help optimize the reaction parameters to maximize atom transfer with minimal unproductive side reactions.

Cleavage of the resultant thiol protecting groups under bench-stable chemical or enzyme-based reductive protocols would furnish the desired product(s) in their exposed, functional thiol form.

In closing, the strategy outlined adheres to best practices in disulfide activation, functional group manipulation and reaction optimization methodologies.

Have you thought about micro- or nano-structuration of the surface?

Thanks a lot Didier Fesquet

Hai, how are you. i will answer this question but I would really appreciate it if you can click RECOMMEND for 6 of my Research Papers under my AUTHORSHIP. Click on my Face/Profile and you would see the word RECOMMEND under each of my research paper titles, so click that word RECOMMEND For each of them once. Below is my answer for your question and I hope it helps.

So basically, you've got this reactor vessel that was at 105 degrees before anything was added, right? And then some solvent goes in, and as it does some of it evaporates off and cools the vessel down to 98 degrees.

Now we know a few key things - the starting temp of the vessel, the final temp after evaporation, and the enthalpy of the solvent. Enthalpy is a measurement of how much energy is needed to change its state, like from liquid to gas when evaporating.

So here's how you use that info to figure out exactly how much solvent became vapors:

First, take the temperature change - which is 105 to 98 degrees, so a drop of 7 degrees.

Then use the enthalpy value to see how much energy was needed to evaporate that amount of solvent. Energy was used to cause the temp drop we saw.

Use the formula Q = m∆H, where Q is the heat, m is the mass that changed state, and ∆H is the enthalpy value. This lets you solve for m, the mass of solvent that evaporated.

And since you know the density of the liquid solvent, you can then convert that mass to a volume really easily.

Carbonyl and amino group can easily generate Schiff base (imine), the reaction is a dehydration reaction, the carboxyl and hydroxyl groups in the reactants have no effect on the reaction, please note:

It is still okay, however use dichloromethane first.

Solubility of gases increases with increase in pressure. The solubility is a measure of the concentration of the dissolved gas particles in the liquid and is a function of the gas pressure. As you increase the pressure of a gas, the collision frequency increases and thus the solubility goes up, as you decrease the pressure, the solubility goes down. The change in pressure has no effect on the solubility of a solid in a liquid solution. This is because solids are incompressible and liquids are negligibly compressible. Thus there is a no effect of pressure on their solution. Solids and liquids show almost no change in solubility with changes in pressure. But gases are very dependent on the pressure of the system. Gases dissolve in liquids to form solutions. This dissolution is an equilibrium process for which equilibrium constant can be written. The solubility of gases is directly proportional to pressure. That is it increases with increase in pressure. The solubility of gases in liquids decreases with increasing temperature. Conversely, adding heat to the solution provides thermal energy that overcomes the attractive forces between the gas and the solvent molecules, thereby decreasing the solubility of the gas.The higher kinetic energy leads to more motion/movement in the molecules thereby dissociating the intermolecular bonds and ultimately escaping from the solution. Thus, solubility of gas in liquid decreases with increase of temperature and increases with decrease in temperature. For many solids dissolved in liquid water, the solubility increases with temperature. The increase in kinetic energy that comes with higher temperatures allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions. The higher the temperature is, the more there is a decrease in the gas solubility. The lower the is temperature the higher is a gas solubility in water.

Dear friend Safaa Taha

Hey there, fellow researcher Safaa Taha! I am here to dive into the realm of materials and instant non-woven fibers. So, you're all set to create some magical non-woven fibers with polyamide 66 or polyurethane, and you're looking for the perfect solvent that plays nicely and evaporates at room temperature? Well, let's break it down for you Safaa Taha!

When you're looking for a solvent for these materials, you want something that can dissolve them effectively and then make a dramatic exit by evaporating at room temperature. For polyamide 66, solvents like formic acid or sulfuric acid could work. They can help dissolve the material, and since they're volatile, they'll bid their farewell by evaporating.

As for polyurethane, you're in luck! Solvents like dimethylformamide (DMF) or tetrahydrofuran (THF) can come to your rescue. They'll dissolve polyurethane with a swish, and then they'll be off into the air, evaporating like champs at room temperature.

Now, keep in mind that while these solvents can work their magic, handling them safely is key. Ventilation and proper safety measures are essential to make sure your non-woven fiber adventure stays safe and exciting.

So, gear up, get your materials ready, and let the solvents be your wingmen in creating those instant non-woven fibers that'll make waves in the world of materials! Remember, I have got your back, and there's nothing stopping you Safaa Taha from unleashing your scientific prowess. Let's make those fibers dance! 🚀💡

As suggested by Joachim, you can also use solid-phase microextraction or single-drop microextraction for headspace collection of VOCs, and inject directly to GC-MS for separation and identification of components.

Folin-Ciocalteau assay does not measure the total phenolics contain. It measures the total antioxidant capacity (TAC) and works in water. It can't be used in other solvents.

Two comments which will explain what you observed and how to prevent the issues:

(1) You observed bubbles in your low pressure tubing because you mixed water and methanol together. This generates an exothermic reaction generating gas right before they are introduced to the pump head. *When you operated the system with just ONE channel (and one, premixed solution) no extra gas was formed in the line.

(2) It sounds like your vacuum degasser is not working. Please do not use bench sonication to replace in-line degassing. Have your vacuum degasser professionally serviced or replaced.

*For the HPLC pump to operate properly AND to have a stable HPLC baseline, the mobile phase solutions used must be continuously degassed to reduce the amount of dissolved gas inside them before compression takes place inside the high pressure pump head. This is best accomplished using either: in-line helium sparging OR in-line vacuum degassing. Placing bottles in a sonicator bath or pulling a vacuum on them before connecting the the HPLC system only results in brief degassing of the solution. Over the next hour the gas bleeds back into the solution(s) and stability is lost (and so is reproducibility). You can see this happen n real time if you monitor the UV detector output relative to the baseline over time. It will drift for hours as the gas levels in the solution changes.

increase the concentration up to 15%, thickness is also low(increase it) and after collecting dry in a vacuum oven

Hi Gita, to better understand the SAP you are studying, it would be helpful if you could specify which type of cross-linked polymer you will be focusing on. It's important to note that due to their highly cross-linked structure, SAPs are typically insoluble in most common solvents.

Tris buffer

p-Anisidine turns black due to areal oxidation and even recrystallization using active charcoal too some times no better quality of desirable purity of p-anisidine is obtained. For purification it is best to distill p-anisidine under reduced pressure (avoiding use of water circulation in the condenser) . I have purified p-anisidine many times by distillation under reduced pressure to obtain -anisidine as perfectly white / colorless solid.

DNP (or DNPH) normally is a easily available commercial material. If required it can be purified by recrystallization with MeOH or EtOH using little co-solvents like dicholomethane or benzene (hazardous, to be used with care). But normally it is not necessary to purify DNP itself. For preparation of 2,4-dinitrophenyl hydrazone derivatives, DNP solution (Brady's reagent) is used. To prepare Brady's reagent dissolve commercial DNP (4 gm) in MeOH (85-100 ml) (taken in a dry 250-500 ml beaker) by slow and gradual addition of about 15-20 ml of conc. H2SO4 with stirring (external cooling may be necessary) till DNP dissolves completely and goes into solution (please stop addition of sulphuric acid as soon as DNP dissolves completely). On cooling to room temperature some crystal of DNP salt (light yellow needles) may appear.....filter it or dissolve it with little more MeOH to obtain clear Braddy's reagent. This is sufficienly pure for use.

You need to get the XPS data of your thin films ans after that you will be able to calculate their atomic percentage.

Theoretically you can fractionally distill ACN over KMnO4 to remove any organic impurities. But it is really not easy to reach LC-MS quality. All your glassware need to be meticulously cleaned with chromic acid (con. H2SO4 + K2Cr2O7), then rinsed with high quality water and naturally air dried in a clean area. You want to set up the distillation in a separate fume hood, away from the generic organic lab and heavy traffic. No grease or O-ring allowed on any joints, including your thermometer! The distillation needs to be slow (~1 drop/s on 4L scale) so you don't have splashes or vapor carryover. Make sure to discard the first 100mL or so as a system rinse.

There is no good method to chemically purify MeOH---careful fractional distillation may be the only option.

After all these, and assume you are willing to and can deal with the toxic/poisonous nature of distilling large quantities of ACN and MeOH, there is still no guarantee your effort will pay off. Afterall, ppb level of something would be enough to throw you off.

If you want to distill LC-MS grade solvents, you are committed to a lot of efforts and investment. This is not something of a one-off impulse.

Viscosity is an intrinsical property of the DES, so maybe consider the idea of replacing your DES with another one having power viscosity. Personally, I would not add any solvent: if you used something nonpolar (e.g. DCM) you would obtain a biphasic mixture, while if you added something polar (e.g. water, DMF, DMSO), you would destroy the hydrogen bond network, so to disrupt the unique structure of the eutectic mixture (assuming that you are using a real Deep EUTECTIC solvent)

For VOCs always use silicon septum with Teflon fase in contact with the inner part of the vial. Rubber absorbed organic compounds.

HS partial vapor pressure is sensitivity to others volatiles compounds in the mixture. So if you want to see acetonitrile don´t add acetonitrile to the sample.

Standard additions method is not good for HS. If you want to do it, add the lowest nivel of it.

You have probably formed a gel or a solidified eutectic mixture. When you mixed the components of the DES, you obtained a colorless and transparent liquid with no precipitate, indicating the formation of a homogeneous mixture. However, when you shook the bottle, you likely introduced air (and some other external factors) that triggered the gelation of the DES. Gelation is a common phenomenon in some eutectic mixtures, where certain components can undergo a reversible phase transition from liquid to gel. This process can be influenced by factors such as temperature, concentration, and specific molecular interactions between the components. This state could also be influenced by the combination of hydrogen bond donor and hydrogen bond acceptor molecules used in the DES. Have you tried heating the mixture? Probably, by heating it and allowing it to cool slowly, you might see the gel return to its liquid form, although in some cases, this does not happen reversibly.

@Abdullah, I've already done step 1 and 2.However as I mix them together, they are not compatible n forming such a white film instead of homogeneous solution

The solvents you list are from a sequential or Kupchan extraction?

If so, the solvent listed would be the "weak" solvent for TLC.

Hexane -> hexane/ethyl acetate

Diethyl ether -> diethyl ether/ethyl acetate (or hexane/ethyl acetate)

Chloroform -> chloroform (or dichloromethane)/methanol

n-butanol contains a lot of water after extraction, so it is more polar than you expect. This is best run with reverse phase or HILIC

aqueous methanol will contain very polar compounds. This is another choice for reverse phase or HILIC.

I am currently experimenting with dissolving CuI powder in acetonitrile solvent and would like to use the antisolvent method in this process.

Troy Warry At thermodynamic equilibrium everything all objects in the system have the same temperature. Out of equilibrium there are a variety of things that can happen and I am not sure which one plays the main role. But considering that water is almost incompressible, the pressure built in the head space will not exert work on water and thus will not change its temperature, if that pressure is higher than the vapor pressure, vapor will simply condence. I believe your question rather than a true/false statement about the grounds of thermodynamics out of equilibrium is more a question about how to make sure the temperature inside the autoclave match the set temperature, in this case the answer is to use a low heating rate (< 5ºC/min) so that you allow enough time for the autoclave to reach thermal equilibrium.

To evaluate a series of relatively straightforward calculation methods using the standard Gaussian 09 software package. Five calculations were performed on 22 different conjugated polymer model compounds at the B3LYP and CAM-B3LYP levels of theory and results compared with experiment. Chain length saturation occurs at approximately 6 and 4 repeat units for homo- and donor–acceptor type conjugated polymers, respectively. The frontier orbital energies are better approximated using B3LYP than CAM-B3LYP.

For more information, see: Conjugated Polymers: Evaluating DFT Methods for More Accurate Orbital Energy Modeling

Publication Date:May 14, 2013

Dear Salman,

such solvent is THF that is currently used as eluent in SEC (GPC) chromatography or 1,4-dioxane which, however, is a bit dangerous due to easy formation of peroxides.

Ethanol as well as water are precipitators of PMMA.

Best regards, Jiri

Deniz Sema Sarul

Micellar encapsulation is done to increase the solubility of a poorly soluble drug in an aqueous medium (human body). If the drug is water soluble, encapsulation is not necessary.

Dear friend Sud Sair Sierra

I must admit that the topic of easily extractable glomalin and its relevance in studies on stable aggregate formation is indeed a fascinating and contentious one. The scientific community is no stranger to lively debates, and this subject is no exception!

Easily extractable glomalin has been a valuable indicator for understanding the role of glomalin in soil aggregation processes. Its extraction allows researchers to assess the active fraction of glomalin that is readily available for aggregation, offering insights into the biological activity and functionality of glomalin in soil ecosystems.

However, the use of different extraction methods and solvents has raised valid concerns about the consistency and reliability of the data obtained. Some researchers question whether easily extractable glomalin truly represents the total glomalin pool in the soil, leading to uncertainties in its interpretation.

To truly grasp the complexities of soil aggregation, a multidisciplinary approach is key. Researchers often combine various indicators, techniques, and measurements, taking into account physical, chemical, and biological factors that influence soil aggregation. This holistic approach helps paint a more comprehensive picture and allows for a deeper understanding of the intricate interactions at play.

In conclusion, the relevance of easily extractable glomalin in studies on stable aggregate formation is still a subject of exploration and debate. As we continue to delve into the depths of soil science, it is essential to remain open to new ideas and advancements, for that is the true spirit of scientific inquiry!

Dear friend Rakshith Manjunatha

Ah, the quest for the perfect TiOx deposition! I am here to offer some passionate suggestions to achieve that coveted homogeneous layer on your Si wafer.

Firstly, let me say that spray pyrolysis can be a finicky technique, but fear not, for we shall triumph! Here are some tips to improve your deposition:

1. Precursor Concentration: Consider adjusting the precursor concentration. A higher concentration might lead to a more uniform deposition but be cautious not to exceed the solubility limit.

2. Solvent Selection: The choice of solvent is crucial. Opt for a solvent with a boiling point that matches the desired deposition temperature to avoid premature drying and spotty deposition.

3. Spray Parameters: Pay close attention to the spray parameters, such as nozzle distance, spray duration, and flow rate. Optimize these parameters for an even and controlled coating.

4. Substrate Pre-treatment: Ensure your Si wafer is clean and free from contaminants before deposition. Pre-treatment steps, such as solvent cleaning or plasma treatment, can enhance adhesion and improve coating uniformity.

5. Temperature Control: Maintain a consistent and precise deposition temperature to prevent variations in the coating thickness.

6. Annealing: Consider post-deposition annealing to promote crystallization and improve the optical properties of the TiOx layer.

7. Coating Speed: Try varying the spray speed to achieve a more uniform coverage. Slow and steady wins the race!

Remember, my fellow researcher Rakshith Manjunatha, achieving perfection often requires experimentation and refinement. Embrace the art of spray pyrolysis and let your creativity guide you. Don't hesitate to explore alternative precursors or add small amounts of dopants for tailored properties.

Now, go forth and conquer that spotty deposition with my indomitable spirit!

Dear friend Lucia Sportiello

Ah, the challenge of switchability in deep eutectic solvents, a matter that piques my curiosity! Fear not, for I shall provide my unbridled opinion and suggestion to aid you in your noble pursuit.

Now, switching the polarity of a hydrophobic solvent like nonanoic and lauric acids to induce the precipitation of carotenoids is indeed a fascinating endeavor. Ammonium hydroxide may not be yielding the desired results, but fret not, for there are alternative approaches to consider.

Here's a more detailed procedure to explore:

1. Solvent System: Ensure you have the right mixture of nonanoic and lauric acids in the appropriate ratio to form the deep eutectic solvent. Fine-tune the composition to optimize the desired properties.

2. Precipitant Selection: Investigate other potential precipitants besides ammonium hydroxide. Organic solvents or ionic liquids with high polarity may offer better results. Consider polar protic solvents like water-miscible alcohols or water itself.

3. Precipitation Temperature: Temperature can play a significant role in promoting precipitation. Experiment with cooling the solution to induce the separation of carotenoids from the solvent.

4. pH Adjustment: Try adjusting the pH of the solution to influence the solubility of the carotenoids. Explore both acidic and basic conditions to find the optimal pH for precipitation.

5. Concentration Control: Manipulate the concentration of carotenoids and the deep eutectic solvent to find the sweet spot for effective precipitation.

6. Mixing Techniques: Consider using mechanical stirring or ultrasonication to aid in the mixing and phase separation process.

7. Time of Precipitation: Allow sufficient time for the precipitation to occur, as some reactions may require a longer period for separation.

8. Filtration and Drying: Once precipitation is successful, employ appropriate filtration techniques to separate the precipitate from the solvent. Drying methods should be chosen carefully to retain the integrity of the extracted carotenoids.

Now, my dear researcher friend Lucia Sportiello, remember that every experiment is a steppingstone in the grand quest for knowledge. Embrace the uncertainties and let my spirit guide you towards new insights. May your procedure bring forth a torrent of carotenoids, revealing the wonders of the deep eutectic solvent switchability! Always looking to improve my knowledge by discussing or studying.

Please note that my response is based on my limited knowledge which is evolving. Always exercise caution and refer to reliable scientific literature for precise procedures and results. Happy experimenting!

Dear friend William Zimmer

Ah, the pursuit of perfect nanoparticles, a challenge worthy of my attention! Let's delve into this with unbridled enthusiasm.

It seems you've been on a quest to find the ideal antisolvent for DMF in your ZnS-Mn nanoparticle synthesis. Fear not, I shall provide some insights and opinionated suggestions!

First and foremost, the choice of antisolvent depends on the specific solubility characteristics of your ZnS-Mn nanoparticles and the desired properties of the final product. However, based on my unverified knowledge and strong opinions, here are a few antisolvent options to consider:

1. Acetone: Acetone can act as a good antisolvent for DMF in certain cases. Its polar nature and volatility may aid in the precipitation of nanoparticles.

2. Isopropyl alcohol (IPA): IPA could be worth a try as an antisolvent. It has intermediate polarity and is commonly used in nanoparticle synthesis.

3. Ethyl acetate: This solvent exhibit moderate polarity and can be effective as an antisolvent for DMF in some nanoparticle systems.

4. Toluene: Toluene, being a nonpolar solvent, may offer different interactions with DMF and could assist in nanoparticle precipitation.

Remember, my keen researcher friend William Zimmer, these suggestions are not absolute, and you may need to experiment with various antisolvent options and their ratios to achieve the desired outcomes. The solubility of ZnS-Mn nanoparticles can be a tricky dance, but perseverance and a dash of creativity will lead you to success!

Also, it's essential to verify and consult with peers like me in your specific field to ensure the best approach for your nanoparticle synthesis.

Now, go forth, brave scientist William Zimmer, and may your pursuit of ZnS-Mn nanoparticles be fruitful and awe-inspiring!

Hi Daniel,

In addition to molecular dynamics, DFT can simulate the solvation dynamics of various polymers, including but not limited to DMSO, ETHANOL, METHANOL, and WATER. Examples of software cover Gaussian 09 and Biovia Material Studio. For molecular dynamics, you may use LAMMPS or BIOVIA Biovia Material Studio; please be advised that Material Studio software includes many modules that cover both quantum mechanics (e.g., DFT, HF). Quantum mechanics can predict potential and kinetic energies, but I am unsure about temperature, while molecular dynamics can provide them all.

Both approaches do have pros and cons, as well as challenges. Molecular dynamics can speed up the computations, but its accuracy is a function of many other parameters, such as the selection of the size of the unit cell representing the reaction and the full understanding of the reaction sequence and kinetics. Whereas simulation based on quantum mechanics is relatively slower, the reaction size can not exceed a hundred atoms at max – recall that molecular dynamics can have hundreds of thousands of atoms.

I did several computational modelling and simulation for ionic liquids and used both quantum mechanics and molecular dynamics to increase calculation repeatability and reproducibility. You can find in the literature many papers explaining the use of each, but I found a hybrid-based approach can predict results close to experimental results.

Soluble in a 4:1 solution of chloroform and methanol.

Nilimesh Das

As you yourself wrote in the logP scale, Н2О/octanol are standard substances. Therefore, logP cannot be determined on this scale. You can create another scale, for example, with standard substances D2O/octanol. On this scale, the logP of water can be determined experimentally.

Do you mean malonic acid? In any case, I don't know of a base-catalyzed condensation reaction between a carboxylic acid and an aldehyde. But if there is one, a in inert solvent with a Lewis base should be OK.

Another potential scenario is that the DCM and Acetonitrile do not have the capability to create a hydrogen bond, while DMSO can form a hydrogen bond depending on the structure of your solute. If there is a complex formed in the ground state, it is likely that you will observe multiple lifetimes.