Science topics: Chemistry
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Chemistry - Science topic

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds.
Questions related to Chemistry
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According to "Handbook of Chemistry and Physics 86TH Edition 2005-2006", it says : 0.134 g/100 g water at 25 deg C; soluble in acid. Based on Wikipedia, it is much less soluble in water and soluble in HF. Some chemical websites show that it's soluble in H2SO4, HNO3, however, insoluble in HCl. I was confused. From my practice, it works, but i wanna know the correct chemical equation. More valid information, details will be better, thanks a lot!
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The conversion of F- to HF drives the apparent solubility.
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I am going to perform a membrane autopsy of a reverse osmosis membrane to investigate fouling. I know how to do it based on research papers that i have read but I need a standard procedure describing the steps to be followed.
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I recently computed an Absorption and Emission Spectra of AlexaFluor fluorescent Dyes (AF-488 & 594) using TD-DFT/B3LYP/6-31+g(d,p)/DMSO/IEFPCM-Solvent Model. I also tried with CAM-B3LYP but the results are same.
What I've got is that my computed spectra are much broader over a long range of wavelength in comparison to the experimental spectra. Can someone please give a explanation for this? Although I've reached a comparable lambda max, yet my spectra are much broader.
I've attached the Experimental and Theoretical Spectra of AF-488, Yellow line: Theoretical || Blue-Line: Experimental
Thank You :-)
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You can try one more thing. TD-DFT calculates transition, not spectra, and latter on an appropriate FWHM is added around that transition (0.4 eV in GaussView). You can play with the width and see and what value your theoretical and experimental matches closely. In Chemissian software you easily vary this FWHM.
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I'm wondering if you could suggest highly viscous solvent which is non-polar or slightly polar and can't form H-bond interactions.
Most preferrably: a glass forming solvent at low temperatures to be used in UV-Vis measuremens.
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Hi Sk Imadul, Thanks but i need more viscous solvents at least > 30 cP
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Generally, most of the research papers talk about the performances of a Li-ion half cell, coin cell or pouch cell. Do those performances are comparable with other shapes (cylindrical, prismatic) of lithium ion cell of same chemistry?
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Nilanjan this simple graphic might be useful in general terms. Polymer, Poly and Pouch are interchangeable.
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Hello,
I need to prepare a polyethylene glycol hydrogel, but have only limited supply to chemicals, so is there any crosslinking agent (except citric acid) that I may have access to and is able to crosslink PEG, preferably at room temperature.
Physical crosslinking like freezing and thawing (does probably not work) is also a possibility and would be preferred by me, because else I have to exchange the crosslinker-hydrogel polymer with my battery electrolyte, which takes a lot of time.
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You can use PEG di-acrylate (commercially available) with V70 (radical initiator) at 40°C or 50°C, leading to the formation of a PEG hydrogel.
If you want to fasten the crosslinking reaction, you can maybe use another radical initiator, which is more reactive than V70. You can also play on the Mn of the PEG, to tune the mechanical properties of your hydrogel.
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"At the moment only about 300 ionic liquids are commercialized" This information I have get from one Chemistry thesis of 2017. In the case of Ionic liquid based surfactant what should be number? How to get this information?
Thanks in well advance
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All liquid detergents worldwide are based more or less on sodium lauryl sulphate, which is an anionic surfactant. Shampoos, hand washes etc also contain anionic surfactants. Check out the link below.
Cationic surfactants are widely used in disinfectants and antiseptics again worldwide. Cetyl trimethyl ammonium bromide is one of the most commonly used ones. IF you broadly search for quaternary ammonium compounds you will find so many commercialized.
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I have tried Felder, Smith & Vaness, Perry, Dean, among other chemistry books and I still can´t find the heat capacity constants for Diethylene glicol and ethylene glicol, does anyone know another source? Thanks!
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Dear Barbara Frias Camarena
The following book could help you
Regards
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Hello,
for already determined distribution coefficients in different systems aqueous solution/resin, via gamma spectroscopy, Is there a way to determine a stability constant in order to strengthen the description and discussion of the data?
The only available data is the gamma measurements.
Redoing the experiment via the pH determination will be an entirely different endeavor.
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Actually the ligand coated on the resin is 40% (w/w) so I have it. But I do not know the formula by which I can calculate the constant.
All of the samples I used were measured with radiotracers so their quantity is low enough and can be calculated in moles easily.
On the other hand I can not measure pH first because the samples are long gone and new ones will take to much resources.
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hi...everyone i want to communicate someone who working/ worked in water analysis
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Hi,
You can find teachers or students work or studying in analytical chemistry in campus or college. Most of them would know how to do water analysis.
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Is it possible to create some nanostructure so as to absorb the entire solar spectrum. If not then What are the major challenges in this field...?
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Black colored metal oxides have the capability to absorb the complete visible and near infra-red light that leads to its efficient application in photocatalysis. Frequently used methods to prepare black TiO2 involve oxidation of low valence Ti compounds, low/high pressure reduction of TiO2 and many more. Black colored metal oxide by hydrogenation offers a cost effective method to improve the visible light activity.
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I have a multilayer film (A/B/C/PET/PE). PET and PE are the last layers. I want to laminate this multilayer film to another PE film in a PE to PE manner (A/B/C/PET/PE-to-PE). The lamination is not working properly. What could be the cause? Can PET affect the chemistry of PE
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Well, the answer to your question (problem) is stated; low energy surface of PET substrate.
Now, if you want to make the adhesion then you need to modify (denaturalize) the surface substrate as using laser beam, electrical discharge (corona), or making holes in the substrate.
Please, let us to know your thoughts please.
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Hi all
I have an equation of the form CxHyOz---->(decomposition) aCO + bCO2 + cCH4 +d H2
how can i get the values of a, b, c and d from elemental and proximate analysis of biomass?
x,y,z are unknowns
Thanks
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You can use BS EN 15104:2011 Standard by CHN instrument.
Also, refer to scientific articles about biomass analysis.
Best Regards
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I want to do a chemistry between two compounds. Only the amine groups of both these compounds are free for conjugation with each other. What linker is best suggested for the process?
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There's many ways to do this. This is a classic problem in bioconjugation chemistry. I highly recommend to look at the following link or Hermanson's textbook on Bioconjugation.
I agree glutaraldehyde is easiest way but often leads to polymerization, which can be controlled by reducing the glutaraldehyde concentration and also carrying it out in a cyanoborohydride coupling buffer. All reactions have side reactions but there are conditions that you have to identify that increase the selectivity of a desired reaction.
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I researched two highly cited journals publications (2017-2018) and observed that more than 55% papers on very specific research topics are published by 13 research groups from 5 countries. Is really only 13 research groups are capable for the highly cited research load of the world?
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This is a very good question.
In my opinion, the whole process "of conducting research, publishing it, and citing" is moving towards being more politicized. They may call it globalization but, apparently, this is a sort of colonization in which research endeavor in certain areas cannot progress unless it follows the lead of specific groups in other "far" countries. This way, the "masters" can be sure that they stay at the top while the others lag behind.
The story is much longer with many details... a good follow-up is required for writing a "review" or a "book" on this subject & the researcher can support it with statistics & figures.
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what exactly the NaCl does to the surfactant means what is the chemistry involved ? Does it have any relation with the CMC ?
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Ionic surfactants:
Electrolyte (e.g. NaCl) decreases the cmc. Theoretical treatments have related this to the thickness of the electrical double layer surrounding the micelle. This reduces the repulsion between the head groups.
An empirical relationship for the electrolyte effect was given many years ago by Corrin and Harkins: log(cmc) = -a.logC + b,
where C is the total counterion concentration. The constants a and b depend on the ionic head and the temperature. [Original paper: J. Amer. Chem Soc. 69, 683 (1947)]
An example of the magnitude of the effect is our data for a commercial alkane sulfonate: cmc about 0.4 g/L without added electrolyte cmc about 0.02 g/L in 0.1 M KCl [Tenside Surf. Det. 47, 28-33 (2010)]
Nonionic surfactants:
The changes in the cmc are generally smaller than with ionics and are thought to be due to the effect of the electrolyte on the hydrophobic groups (salting out or salting in). However, there will presumably also be some interaction with the hydrophilic group.
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Hi all,
I have some confusions regarding ultimate (elemental) and proximate analysis
1) Should the sum of all percentages be always 100 (for both analyses)?
(Figure 1 attached, doesn't make sense to me)
for balsa wood, C+H+N+S=100
for Eucalyptus, Ash+C+H+N+S+O=100
for rice husk, Ash+C+H+O=100
2) Is ash included in elemental analysis?
3) Is elemental analysis always based on dry/wet basis. what should we consider (dry or wet) if not mentioned?
4) If in elemental analysis, sum of all elements percentages equals 100, and humidity is also given (additional to 100%), then what is it, dry or wet basis elemental analysis? (figure 2)
Thanks
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Dear Sir. Concerning your issue about the elemental and proximate analysis, wet and dry basis . In the proximate analysis, moisture, ash and volatile matter are determined. There are standard tests to determine proximate analysis. Moisture is determined by drying 1gm of sample at 105o C for 1hr. Weight loss is expressed in % of initial weight of sample. The main chemical elements in coal (apart from associated mineral matter) are C, O, H, N and S. The chemical analysis is very important to calculate material balance accurately and calorific value of coal. I think the following below links may help you in your analysis:
Thanks
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Evaluating academic faculty for promotions often include assessing their teaching abilities. Is it sensible to base these on Student Course Evaluations?
Geoffrey Alderman wrote in the Gaurdian that a reason for the decline in academic standards has been the 'increasing and increasingly stupid use of students' course evaluations as pivotal factors in the academic promotion process.'
Does anyone have a deeper insight on how the use of such student evaluations have impacted faculty at their own institutes? Have they led to dumbing down?
How much confidence would you have in the teaching ability of the applicant if the evidence was exclusively based on Student Course Evaluations?
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I agree with so many of the comments, if they are to be used, they must be just one element in the evaluation process. If they are administered and collected, they must have a purpose. They should be a resource to potentially identify problems within the instructional setting, but not as confirmation of a problem. Validation only after a deeper examination into a possible issue.
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I'm not an expert in chemistry but I hope it to be a straight forward question.
The situation is, as shown in the figure below, I'm trying to etch a semiconductor in KOH solution (4M concentration) at room temperature. There is a negative sheet charge with a density of P (C/cm2) located at the bottom surface which repels the OH- from accessing the semiconductor. However, the etching can progress along the sidewall until the distance (d) is too close and the diffusion force and electric field reach an equilibrium. I'd like to know how to calculate this distance d. Thanks in advance.
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You have OH ions, then quantified via pOH.
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I am interested in new Sn(IV) based products, without a direct bond to a C-atom , what makes these products not toxic.
Is your work going into this direction , or is it more for anti-fouling applications?
Thanks for your information.
Best regards,
Dr.Joop Koster
JBK Research & Consulting
CH-1260 Nyon
Switzerland .
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I am looking for a procedure of determining nitrates and phosphates in water samples using UV-Vis.
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Lokesh Kumar has said it all. I cannot add to that.
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By best, I mean which could easily extract out soil organic matter such as amino acids plus which could easily be available or synthesised using basic chemicals.
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A new soil extractant (H3A) with the ability to extract NH4, NO3, and P from soil developed and tested against 32 soils, which varied greatly in clay content, organic carbon (C), and soil pH. The extractant (H3A) eliminates the need for separate phosphorus (P) extractants for acid and calcareous soils and maintains the extract pH, on average, within one unit of the soil pH. The extractant is composed of organic root exudates, lithium citrate, and two synthetic chelators (DTPA, EDTA). The new soil extractant was tested against Mehlich 3, Olsen, and water for extractable P, and 1 M KCl and water‐extractable NH4 and NO2/NO3. The pH of the extractant after adding soil, shaking, and filtration measures for each soil sample.
1. Morgan Extraction Reagent which was introduced in 1941
2. Mehlich introduced an universal extractant, frequently referred to as the Double Acid extractant, for assaying acid sandy textured soils.
3. The ammonium bicarbonate‐DTPA extraction reagent for use on alkaline soils was introduced.
4. Wolf modified the Morgan extraction reagent by adding DTPA to it. In 1984, Mehlich described his Mehlich No. 3 extraction reagent for use on a wide range of acid soil types.
All above extraction reagents can be assayed using a multielement analyzer such as the inductively coupled plasma emission specterometer for both the major elements and micronutrients in the obtained extractant.
The soil extract can be prepared by mixing 5g of soil in 1L H2O mix well, filter and then autoclave.You don't have to use soil extract to isolate Actinomycetes you can use any other medium that contained two different antibiotics for inhibition of fungi such as nystatin and streptomycin for inhibition of bacteria.
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I was wondering if anybody has worked with chemistry of these two cross-linkers and have characterised by FTIR or MS whether they are cis/trans or S/R isomers?
Apologies: I am not a synthetic chemist by training.
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does the diminution of cis and trans in elastomer indicate scission ? (abstraction of hydrogen)
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Hi,
I am trying to modify sulfonic acid group to conjugate with carboxylic group or amine group in protein.
I have hard time finding chemistry to modify sulfonic acid for the conjugation.
Can anybody let me know if there are options?
Thanks
best,
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The conditions of reaction depend on the structure of your compound containing -SO3H group. I think that you should check methods using SOCl2 or PCl5. The disadvantage is that these reagents can also react with hydroxyl and carboxyl groups.
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I am wondering if one could ideally create a formula inputting the stokes/hydration radius of the ions involved and the charge of the ions to estimate the change in melting/boiling point of water per gram of salt used?
I am not sure if a direct correlation can be made using the hydration radius, but my intuition tells me that an ion which strengthens the hydrogen bonds between the water molecules (like e.g. Lithium which has a large stokes radius) should be able to increase the boiling point of water by a few degrees, whereas an ion which destabilises the hydrogen bond cluster (and therefore has a small stokes radius) like Rubidium should decrease the melting point of water.
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The presently available theories of aqueous ionic solutions are too crude to deal with problems of the sort you address and limited to very dilute solutions.Ionic size definitely affects colliigative properties and phase equilibria at higher concentrations since it is a first order measure of the specific local interactions of an ion with hydration waters in addition to the ubiquitous screened Coulomb interactions crudely treated via Debye
Hueckel like theories and the ionic strength concept.Unfortunately computer simulations of dilute to moderate molality salt solutions are also
not feasible due to the long range Coulomb interaction and the complex nature of water and ion water interactions.For the time being one has to resort on fits of experimental data etc.
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There are many predatory journals online available and also growing day by day. How to detect that the journal is predatory, As I found there is site where there is list of predatory journals but how we will come to know these sites information is correct or not?
Any other way to find out?
As there is continuous threat that somebody may waste their data in publishing in these journals.
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The best, I found with all the information, that we check with thompson reuter.
Please follow the link below for the all journal list, which are peer reviewed and indexed with Thompson reuters
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I am preparing an optical system in infrared, however I will need to stick two optical components. They are made from CaF2.
Can you recommend index matching-liquid? I am interested in the range 1um-15um. I see that other researchers use paraffin oil, but still i would like to make sure of all possibilities.
Or maybe there are few liquids, that would work eg. in 1um-5um, 5um-10um and so on?
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A few came to mind, but none is perfect. You will need to choose based on your application. Each of these below has certain low absorption window in the MIR and FIR, and the optical dispersion (or refractive indices) for some may need to be further characterized.
(1) Acetonitrile
See "Schafer SA et al., Mechanism of Biliary Stone Fragmentation Using the Ho:YAG Laser, IEEE Trans Biomed Eng, vol 41, no 3, 1994."
(2) Glycerol, 1,3-Butylene glycol, trimethylolpropane, Topicare(TM)
See "Viator JA, et al., Spectra from 2.5-15 um of tissue phantom materials, optical clearing agents and ex vivo human skin: implications for depth profiling of human skin, Phys Med Biol, 48 (2003) N15-N24."
Best of luck,
Kin
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I have two questions.
1) I have a molecule H2N-R-NH2, and I want to react one end using amine coupling reaction to attach SH as the terminal group. That is to day, the final structure is H2N-R-(linker, preferably alkyl chains)-SH. Does anyone know what is the selectivity (one-end functionalization or two-end functionalization) for amine coupling reaction? And is it to purify?
2) I have NC-R-CN, and I want to attach one end to get SH as the terminal group, i.e. NC-R-(linker)-SH. What chemistry is feasible?
Any recommendation on the literature is more than welcome.
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Hello Juan,
is it important for you that specific NH2 reacts? or any of two? is your molecule symmetrical? If you work with 1 equiv. of diamine, there is a good chance to get mono-fictionalized product, which would also be possible to purify. For example, in the paper below:
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I want to know how I can find a specific structure of metal organic frameworks?
I need a molecular structure of Ag-BTC MOF.
How can I get it?
Can anyone help me on this?
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A MOF is not a molecule, so you can't get a "molecular structure", but I understand you meant the crystal structure of that MOF. Of course single crystal (but also powder) diffraction may return you the structure.
A AgBTC MOF does not exist (apparently), whereas its Cu analogous is very well known (HKUST-1). Thus, Ag may be isomorphous with Cu (in this case a powder XRD would b enough) or not. If by chance someone has already prepared and measured it, then it would be listed in databases like Cambridge or others (and the cif file would be freely available).
Anyway, XRD is not the only technique to determine crystal structures. Other diffraction techniques are neutrons or electrons (here stability may be an issue). Or otherwise solid state NMR (here complicated by the magnetism).
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Hello Respected Seniors!
I want to collect samples from the Acid Mine drainage environment to determines the microbial community in that sample. So how we can collect the sample that the chemistry and biology of the sample are not disturb and we can get a significant result.
Hope that i will get a positive response.
Thank you so much.
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Whether you are a student or a researcher, this might be of some interest to you. Not as an answer to your question, but as a source of ideas to consider.
Good luck.
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Hi everyone,
I'd like to verify if my solid phase extraction cartridge is saturated after i tried to purify a serum sample potentially containing drugs?
Thank you
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Prepare a test sample by spiking a similar sample matrix (serum or plasma). Apply the sample to the SPE and fraction collect the flow-through. Continue past your usual sample volume X10. Treat the fractions as samples and reanalyze. I usually did a Protein Crash by adding 3X volume of acidified acetonitrile. Allow the protein crash samples to sit in ice and then centrifuge. Decant the supernatant and analyze for your molecule of interest. The result should identify the breakthrough fraction. You can also elute the SPE to see the maximum drug captured.
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hi Experts
I want to estimate and differentiate the different forms of potassium such as potassium chloride, potassium sulfate and potassium carbonate in the plant ash samples. Please suggest me the best methods and how could i achieve my goal.
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Please have a look at enclosed PDF...
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Dear Friends,
I am working on a R&D project about increasing alkaloid content of Papaver sp. in in vitro conditions. My project manager asks me to isolate codeine from total alkaloids extracts from Papaver culture. Since I have no opinion about the procedure I checked online procedures and only find out cold water extraction way which is not suitable. I have to isolate the final product as pure as possible. Do you have any suggestions about it?
Thanks for your kindly and helpful replies.
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Hello Deniz,
I am working on alkaloids, but haven't worked on codeine specifically, I'm not familiar with it. However, I can give you afew suggestions.
- Cold extraction may work and still give you alkaloids
-Since alkaloids are non-polar, use non-polar solvents to extract. May consider 100% or gradients of the following, n-Hexane and DCM, or gradients of the two with ethyl acetate.
-Purify your fractions and isolate on HPLC
-Next step has two options depending on the availability of your resources:
- Either use a pure codeine if you have it as standard on HPLC or TLC and check which of your purified isolates match with the curve areas or RF of the standard codeine,
- Or, you can check these (Area under curve or RFs) online for pure codeine and compare with your fractions'.
- The one that matches is it. The tricky part is on the isolation, be very patient and sure on this stage.
All the best
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Hello,
I am trying to make a pH controller with Arduino using a solenoid valve. I want to be able to open my valve for a certain amount of time and lower the pH by X amount in a bucket. I am using phosphoric acid. My first question:
Let's say the pH is 8 and I want to reduce it to 7:
0) If the pH is 8 in the bucket this means a concentration of 10-8M?
1) How do I know which acid dissociation constant pKa to use 2.16 or 7.2 or 12.32 (7.2 because it's closest to my target pH?)
2) Next how to I use the HH equation pH = pKa + log ([H2PO4-]/[H3PO4]) ?
3) Lastly how to I account for volume in the bucket I'm trying to change the pH of ?
EXTRA:
4) Any idea how to account for flow rate out of the valve?
Thank you so much!!
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0) The [H3O+] is 10^-8 M
1) + 2) This is not a buffer solution. The equilibrium pH is driven by the dissociation of the acid. Chapters on acid/base dissociation reactions from an undergraduate general chemistry textbook have details of how to handle this type of problem.
3) + 4) Do a mass balance on the system to obtain \rho (dm/dt) = dV/dt = \rho mf_in = Vf_in where mass change or volume change is density times mass flow rate in or just volume flow rate in.
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I want to know if there is a time or duration that is expected for AOC to change and cause bio-film development on membranes. This question is also applicable to pipelines for water distribution. Although the conditions for these two scenarios may differ due to several factors like material properties (membrane and pipes) and surrounding chemistry
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AOC means Assimilable Organic Carbon
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Does anybody know about a free electronic laboratory notebook suitable for synthetic organic chemistry experiments? It should be preferable in a software version, not online. Thanks for your help.
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Hi Dr. Kaufman,
Please check the article attached and the following links:
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When you create pectin from orange peels, lemon juice is added to neutralize the pH and also to neutralize the negative charges in the pectin. How come strands of Pectin contains negative charges? Will adding lemon juice to the orange peels neutralize the negative charges? Also, they use lemon juice in jams, when creating pectin.
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Hello Luke,
Pectin is heteropolysaccharide, which contain charged sugar units, so-called uronic acids, usually galacturonic acid (GalA). Uronic acids have carboxylic group at C6 and thus negatively charged (anionic units). Native GalA is methylesterified in high degree (up to 80% depend on pectin source, i.e. apple, orange peels etc). During alkaline or acid hydrolysis of methyl ester groups in uronic acids we can create even more charged groups from native pectin!
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After synthesizing polymer-drug conjugate via a carbodiimide chemistry, is there any other way to confirm the conjugation between the polymer and the drug apart from NMR, FTIR and UV-vis? Can LC-QTOF plays a part in the conjugation confirmation?
Thank you very much.
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You can try, but to get it standardized with your complex would be cumbersome.
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Dear All,
I have a pH electrode of BNC probe type ,which will give the output as mV .Can any one help me to convert sensor mV values into respective pH values .
Any suggestions /help is highly appreciated .
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1. Choose two buffers, let say pH1 = 7.00 and pH2 = 4.00 and measure the corresponding E1 and E2 (in mV).
2. For a sample with pHx, you measure Ex.
3. Calculate pHx = pH1 + (Ex – E1)(pH2 – pH1)/(E2-E1)
Important notes:
- all buffers and samples must be measured at the same temperature
- use a stabilisation time of about 1 minute for the electrode response
- the instrument must have a very high impedance (500 Gohm, not used in common voltmeters; use a pH/mV-meter in "mV" mode to test the equation)
- use a 3rd known buffer as sample (e.g., pH= 9.00 or 10.00) to very if the sensor response is linear).
- at pH=7.00 , the common measured E is not zero; in the given equation, (Ex – E1) is the correction for this asymmetry
- in the equation, (pH2 – pH1)/(E2-E1) is the electrode slope.
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Hello,
I am trying to use microwave irradiation to synthesis a schiff base using salicyladehyde and phenylamine. Do i need to use a metal like CuCl2 to coordinate the reaction?
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The method can be used without this material
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I developed a device for cutting the TLC plates. This is my new invention and this design is registered. I wish to commercialize this product.
Please let me know if it is useful for daily chemistry purpose.
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Actual Background of invention:
We use scale and paper cutter to cut TLC Plates . Many people cut their hands while doing it,  moreover TLCs are not smooth and it is a time talking process (marking, tracing and cutting etc). 
To overcome these problems, I invented a TLC cutting device which has following features... 
1. It is very easy to use and almost safe to use. 
2. It is very cheap. 
3.  It can be used by any person without any training. Very user friendly. 
4. One can cut various sizes of TLC plates according to the needs. 
5. Ideal for normal chemistry reaction monitoring but can also be used for cutting HPTLC plates. 
6. Can be used for cutting glass TLC plates with suitable glass cutter. 
7. No marking is needed to cut the TLC plates as it is pre-calibrated. 
8. Occupy  same space as that of TLC Plate. 
9. One can see the TLC plate while cutting with transparent version. 
10. Made up of hard and transparent sturdy material so ling lasting . 
11. Comes with variety of materials and can be drafted according to the needs of clients. Some of the versions can be. colour printed.
12. Already tested with my colleagues and it is working fine.
Hope you find it interesting, please let me know if you are interested.
Warm Regards 
Dr Omprakash
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How does this reaction happen that makes the mustard move around in certain path, is there a pattern for this?
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Thank you sir! Sounds right to me.
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I want to ask if determining the seed oil content using gravimetric means such as done in the paper below is appropriate.
There were no chemicals used.
I could not find any other literature supporting this method.
If there are, can you share this with me? please.
Thank you very much.
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Dear Renerio
Please see the following paper.
Hughes, M. (1969), Determination of moisture and oil in the seed of winter rape (Brassica napus) II.-Comparison of extraction methods for the estimation of oil. J. Sci. Food Agric., 20: 745–747. doi:10.1002/jsfa.2740201211
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Some special drugs might be deformed and deactived next to high temperature so it cause many damages for their Productive factory
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It is best to follow the manufacturers' instructions concerning temperature controls for certain drugs. In addition some drugs require a cold chain to keep them safe, therefore using thermo-flasks is acceptable. The below links gives some information on encapsulation and hydrogels
ttps://www.tandfonline.com/doi/abs/10.1080/096374899101256
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What are important topics for research in the field of organic chemistry?
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Continuous flow reaction systems.
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Its just clearly mentioned on the article below:
"The chemistry of minerals obtained from the combustion
of Jordanian oil shale" written by: A.Y. Al-Otoom et al.
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The structure and the strength of organic compound adsorption on mineral surfaces are of interest for a number of industrial and environmental applications, oil recovery, CO2 storage and contamination remediation. Biomineralised calcite plays an essential role in the function of many organisms that control crystal growth with organic macromolecules.
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For example, total number of molecules of Mn, S and O in MnSO4. I only know the molar mass and the total mass I have to prepare. I do not know the number of moles or molarity.
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Calculate he number of moles you have by taking the Mass / molar mass. if you have 1000 grams ; then 1,000 g / 151.001 g/mol = X g moles. Then multiply by Avogadros # = 6.022140857 × 10^23 molecules per g mole. The result is the # of molecules of MnSO4. And there is one molecule of Mn per each molecule of MnSO4, but only two O2 molecules per molecule of MnSO4.
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I have my ZnO nanoparticles and I have to check the zeta potential at various different pH range from 2-12. But usual chemistry of ZnONP tells that they might start dissolving below 5.5 pH or so. In such case how do I go about?
How to prepare sample for just normal zeta measurement and for various pH? Which solvent (I use deionized water as of now)? Concentration?
If i choose phosphate buffer at various pH does that help?
I am very new to this method I have never done this before so I have no clues. If someone can guide me through how to go about from sample preparation to interpretation.
Can DLS be measured with same sample preparation?
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You cannot measure the zeta potential of a system (particles + environment) without taking into account the chemistry. As you indicate ZnO dissolves in acidic environments. Thus there is no concept of zeta potential in such situations. Take a look at: Guidance to improve the scientific value of zeta-potential measurements in nanoEHS Gregory V. Lowry et al Environ. Sci.: Nano, 2016, 3, 953 - 965
DOI: 10.1039/C6EN00136J
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Ifosfamide is one of the most famous and useful drugs for cancer but its very important that you know this pharmaceutical compound has many harmful effects on sick people , one of which is bleeding that is very danger for them and it might be so unbearable .
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For ifosfamide, the dose-limiting toxicity is cystitis, if mesna is not co-admministered. If mesna is co-administered, the dose-limiting toxicity is myelosuppression. When compared with a similar drug cyclophosphamide, ifosfamide tends to induce cystitis and neurotoxicity more often. To suppress these side effects, modification of ifosfamide molecular structure would need to alter its metabolism, so that active metabolite iphosphoramide mustard is produced without urotoxic acrolein and neurotoxic chloroacetaldehyde. That would be quite a challenge.
And concerning increased risk of bleeding, this is a consequence of chemotherapy-induced thrombocytopenia, and this side effect is associated with many anticancer drugs, so it is not limited specifically to ifosfamide. It was reported as most commonly associated with platinum and gemcitabine-based regimens.
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What is spiral modulated spin structure in ABO3 Perovskite (ferromagnetic material) ?
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Please have a look of the attached files.
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I recently conducted a coffee-cup calorimetry experiment in which we attempted to measure if the dissolution of inorganic crystals such as LiCl, NaCl, and SrCl were endothermic or exothermic based on a change in temperature over time plot, including measure the enthapy of solutions, but I'm not sure how to do that.
Methods:
We measured 7.9204 grams of SrCl2, 4.2143 grams of LiCl, and 2.9290 grams of NaCl and decanted these into separate coffee cups filled with 50 mL of deionized of water. (These were about 1 - 2 mole/liter solutions.). A temperature probe measured the temperature change over 600 seconds, recording a measurement twice a second. I've only displayed about 140 seconds of the measurement, because the temperature was just continually oscillating 0.1 degree Celsius after that point as it reached equilibrium.
We made plots for each of the chemicals, where an increasing curve shows an exothermic reaction, and an endothermic reaction displays a decreasing curve. Over time, these solutions (Temperature ~ Time) curves should equalize to equilibrium.
Theoretically, we predicted we could determine if the enthalpy of solution like so ...
Enthalpy of solution = Lattice Enthalpy + (Hydration Enthalpy of cation + Hydration Enthalpy of Anion),
where the Lattice Enthalpy is a measure of the stability of the compound crystal which is at least a function of the charges of the cation and anion, as well as their size, and the structure of the crystal body centered cubic vs face centered cubic, and the hydration enthalpy is the energy it takes to dissolve the gaseous ions after breaking the crystal lattice.
Schematically, the Lattice Enthalpies ( Δ H):
LiCl(s) ----> Li+ (g) + Cl- (g); ΔH = 852 kJ / mole
NaCl(s) ----> Na+ (g) + Cl- (g); Δ H = 787 kJ / mole
SrCl2(s) ---> Sr2+ (g) + 2 Cl- (g); ΔH = 2153
Source:
These Lattice Enthalpies were obtained from Table 18B.4 of my textbook:
Physical Chemistry Thermodynamics, Structure and Change, 10th Edition, VOlume 1, by Peter Atkins & Julio de Paula
Then the Enthalpies of Hydration are these:
Li^(+) (g) ---> Li^(+) (aq); ΔH = -519 kJ / mole
Cl^(-1) (g) ----> Cl^(-1) (aq) ; ΔH = -381 kJ / mole
Na^(+) (g) -------> Na^(+) (aq); ΔH = -409 kJ / mole
Sr^(2+) (g) -------> Sr^(2+) (aq); ΔH = -1443 kJ / mole
Source of Enthalpies of Hydration (Tables 1 - 2):
The Enthalpies of Hydration that I've used are experimental.
Smith, Derek W. "Ionic hydration enthalpies." Journal of Chemical Education 54.9 (1977): 540.
Therefore, the enthalpy of solution for LiCl, NaCl, SrCl2 is this:
For LiCl,
ΔHsolution, LiCl = (852 kJ / mole) + [(-519 kJ / mole) + (-381 kJ / mole)] = -48 kJ / mole < 0, so this reaction should be exothermic and it is as predicted.
For NaCl,
ΔHsolution, NaCl = (787 kJ / mole) + [(-409 kJ / mole) + (-381 kJ / mole)] = -3 kJ / mole < 0, so this reaction should be exothermic.
I've been searching the web about this reaction and most sources say it's endothermic which I my graph shows, but my calculations do not show that. What?
Doing the same kind of mathematics, the Enthalpy of solution for SrCl2 is this:
ΔHsolution, SrCl2 = [2153 + (-1443 - 2 * 381)](kJ / mole)
= -52 kJ / mole < 0, so this reaction should be exothermic.
BUT MY PLOT SHOWS that It's significantly endothermic!
What's going on? Is my mathematics faulty. Am I using too concentrated solutions? Is the SrCl2 that we are using impure or not really SrCl2? I suppose that's possible, but we didn't do any validation because this lab took quite some time. How is it possible that my experiments don't match theory mostly?
Thank you for you for your help.
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Beside enthalpies, the entropy changes are also important. The salts are in crystal forms. They are highly ordered. When dissolves in water, they becomes hydrated ions, which are highly disordered. The entropy changes are significant.
Entropy,
An example on how to calculate the free energy change of the solvation of CaCl2,
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I'm going to make a suspension of Carbon black in order to mix it with another water base suspension and freeze-dry it. considering the point that carbon black does not mix with water properly I need to use another solvent. I tried DMAc but my sample melted during freeze-drying!!! I'm wondering what would be the best option?
Thanks
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Dear Rassoul,
There are relatively few organic solvents that will freeze dry well - DiMethyl Acetamide is not one of them! It may be used for inks, but not freeze drying. Things like tert butanol, water, 1,4-dioxane, cyclohexane freeze dry well. DMSO can be used, but the risk here is having a suitable system for working with agressive organic solvents is the challenge (this is also true for DMAc.) as most dryers are made for water ...
To disperse the carbon black you will need a whetting agent in there, and you need to generate some viscosity in the mix to help it disperse well using a high sheer mixer. It is unlikely from my ancient knowledge of whetting agents (I'm not up to date) that these will not evaporate but will remain behind in the carbon black. Typically carbon black is dispersed into oils, not things that freeze dry well.
Do you really need to freeze dry? Is this the correct process?
Kind regards
Rob
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By looking at the structure of both molecules, I see that both molecules have at least two non-conjugated sigma bonds, making conductivity due to resonance seemingly impossible. I read from this paper " " that the conductivity of polystyrene is about 6.7*10^-14 S/m and polypropylene should have a conductivity somewhere between 10^-18 and 10^-17 S/m.
Some things I didn't consider is the density and porosity of the materials and possibly inter-molecular effects.
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Polystyrene in its molecules contains benzene rings. In benzene rings, electrons are delocalized between 6 carbon atoms and move in the benzene ring without resistance. This property increases the electrical conductivity of polystyrene in comparison with polypropylene. For comparison, you can indicate a pair of diamond and graphite. Graphite has a better electrical conductivity than diamond.
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jcr based impact factor not the other one.
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I am looking for JCR journals not only SJR. Dr. Rajkumar S Yadav . Your link is not of my interest. Thanks
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What are the basic mechanisms or processes that occur polarization in dielectrics?
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I recommend the answer by K. Sreenvias
since the subject is almost prehistoric
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what are the basic differences between 1) Electronic polarization 2) Ionic or atomic polarization 3) dipolar polarization 4) Interfacial polarization?
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I would suggest you to begin to read an old, but still excellent book:
A shorter, but useful text:
Regarding mechanisms of polarization:
For a more complete introduction to dielectric relaxation spectroscopy:
Believe me: it is much more useful to read a full chapter than to look for shortcuts and short answers
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how to determine indirect band gap using UV-VIS-NIR Spectroscopy ?
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If the material does have a well defined bandgap, tauc plot would be incorrect. If the material is highly disordered, it will not have a well defined bandgap. Tauc plot can give you an estimate, but you could use other methods as well, since it is not well defined. There were multiple discussions in the past on this topic.
For an indirect bandgap material with a well defined excitonic bandgap, see the attached paper for measuring the bandgap of GaP (one of the best studied indirect bandgap semiconductors).
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how to draw Cole Cole plot Z vs Z' using impedence Analyzer with explanation ?
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Enclosing one paper of ours on NiFe2O4 ceramics, in this we have used the some different shapes of cole-cole plots, and modeled them, and tried to correlate with he changes in the microsctructure, please go through it, you will be able to understand some explanations based on such analysis
K. Sreenivas
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How to increase the surface activity of low surface energy plastics?
How to make the surface of polyolefins Chemically active ?
Suggest me some practical ways to achieve it.
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Which techniques are currently being used to bond low surface energy plastics ?
How much bond strength can be obtained at most on plastics like LDPE, HDPE, PP?
Any rubber based Adhesive being used for such application?
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Cyanoacrylates (one of them is Super Glue) are instant adhesives that have been used to bond low surface energy plastics for many years. Personally, I have tried to apply Super Glue on a broken polystyrene comb but it did not work.
I found that "an epoxy resin pre-polymer together with a diamine hardener" offered good adhesion for a variety of plastics.
However, the attached link talks about an adhesive "with 2 components" which is claimed to be effective. Needs trying, I think.
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I'm looking for the chemical reaction(s) involved in EROD assay to get a deeper look at its working principle. I've read abut the basic principle mentioned in number of papers, but i haven't come across one which tells about the chemistry of the assay in detail.
Also, which is the best database to find chemical reactions?
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Hello Reema,
I guess, this helps in understanding the underlying biochemistry. This is just a speculation based on information.
1. CYP1A metabolizes xenobiotics.
2. EROD is one such enzyme which is induced by CYP1A while metabolizing xenobiotics.
3. 7-ethoxyresorufin is a fluorophore and substrate for EROD and a competitive inhibitor. Thus, if xenobitoics were high in media, CYP1A and EROD will be activated.
4. Hence conversion of 7-ethoxyresorufin by CYP1A-EROD system will be higher, and can be detected by change in fluorescence.
5. This assay can be considered to other catalase and SOD based assays.
I hope this helps.
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Today, every educational field or domain contains several branches. You first choose one branch of your field to prepare your Master and Ph.D degrees. What is preferable system for you:
1- study the same branch at both Master and Ph.D degrees
or
2-study different branch at Ph.D degrees from Master degree
And, Why?
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I believe that the continuation of research begun in the Masters preferred.
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why is the color of PbSO4 in lead acid plates is black instead of normal white color for lead sulfate after the plates is discharged in lead acid battery ?
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Dear Dr Valerii Kotok
Very good answer, thank you!
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First run of generating the polythionics APPEARED to work, got a turbid white solution with smell of sulfur but 304SS coupon did not crack. I'm looking for particular details about the reagent or setup that will lead to successful test on sensitized coupon of 304.
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So, the original 1888 text says the H2S bubbling needs to be repeated daily for about 2 weeks. afterwhich, the temp is brought to room temp and the sulfurous odor returns, and H2S is bubbled again until the sulfur dioxide smell goes away. ASTM says you "may" have to repeat the H2S bubbling, original text says you will repeat for an extended period.
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What can be the best alternative for EDC, DMAP as catalyst for carboxylates? I want to skip DMAP actually.
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There's an odd esterification method involving CBr4 that's fairly selective, but might work, depending on the structures of your substrates:
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Hi Dear All,
Boronic acids in general form complexes with cis 1,2 or cis 1,3 diols etc. If we want to protect the boronic while attaching it to any polyesters with multi hydroxyl groups. Could somebody give a nice idea to do that?
Kind Regards
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Hello Rashid, here is a really good paper on the stability of boronic esters with various diol ligands and the rates of transesterification from one diol ligand to another.
The paper is on research gate and sciencdirect.
In general mixing a boronic esters and a diol in pentane for several hours, removing the water layer that forms, reducing the solvent volume and passing the concentrated reaction solution through a plug of silica gel with DCM as the eluent is a very effective way of esterefying and purifying a boronic ester. This is the method we often use in our lab. You can find the actual procedure in the SI of the Science paper on my researchgate profile. Here is the link to the paper http://science.sciencemag.org/content/351/6268/70
If you don't have access to Science Journal just let me know and I can upload the SI to my profile. Another common method that is used involves mixing boronic acids and diols in dichloromethane for several hours with a desiccants such as 4 angstrom molecular sieves (the method used in the first paper I mentioned).
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Hi All,
Could some one suggest an easy and efficient way to protect phenyl boronic acid with ethylene glycol?
Kind Regards
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I am trying to protect two OH with Boron, through its condensation with ethylene glycol. this picture with give you an idea.
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I read in an article where I found the term plasma activated HCL , I was wondering how to achieve that?
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following
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How to select the active moiety in any aqueous extract and the chemistry of it?
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Compare results of repeatedly cited literature to pre-screen candidate active compounds from your extract. Then, you can do separation techniques such as chromatography ,i.e. HPLC. However, purification will highly depend on your extraction protocol. For the chemistry of the compound, you can perform NMR spectroscopy.
Best,
Arizaldo
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Dear all,
I need good and up to date resources to find out the applications of nanotechnology at industry.
Thanks
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a lot of the above will depend heavily what industry you look at as there are basically unlimited application examples, and no single source can cover metallurgy, semiconductor industry, building industry, medicine, pharmaceuticals etc.
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Metal oxides can be functionalized easily with any matter but why it is not possible to functionalize metal sulfides with materials such as for example their fictionalization with an Aerogel?
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important question for me, I am following
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I want to conjugate streptavidin with some different peptides to make a target for biotinylated antibody. Need a protocol to do this.
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Humana Press has published a couple of guidebooks with great recipes for peptide conjugation: The Protein Protocols Handbook, and Methods in Molecular Biology (especially Vol 36: Peptide Analysis Protocols).
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I'm interested in identifying examples of high-U and/or Th overgrowths of zircon of magmatic origin. Apart from metamictisation, what features/textures/chemistry are associated with this style of overgrowth?
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Hi Gordon, we published time ago an example of U-Th-rich magmatic overgrowths of zircon in a well-constrained leucogranite. Hope it is useful for you.
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