Posted in Contact Angle, Critical Solution Temperature, D L Williams, DSC, Education, Forensics, FTIR, Hansen Solubility Parameters, LIF, Physical Chemistry, Raman, RER, Science Education, Solubility, Solvent Blending, Spectroscopy, Thermal Analysis, UV-VIS-NIR, XPS

PCHEM and Forensic Chem Lecture Videos

I frequently have seniors who want to revisit the concepts in pchem sit in my 8AM lectures the year after they have had my course. It’s a privilege to have them and an encouragement to see their natural curiosity in action. They seek to firm up their understanding of the quantum world and how we interact with it (i.e. spectroscopy).

In the fall of 2017, I put these students to work videoing the lectures and posting them on the Physical Chemistry at Sam Channel. These videos are essentially raw footage of lecture. The videos could have been greatly improved by adding in the PowerPoint Slides, captioning, cleaning up the audio, and cutting out my “ums” and “uhs”. But these volunteers did not have time to do that, nor did I. I had a CLEANING WORKSHOP to plan and execute!

CHEM 4448 – Physical Chemistry 1
– Quantum Mechanics and Spectroscopy

CHEM4448-Playlist-Snip

CHEM 4449 – Physical Chemistry 2 -Thermodynamics

4449Lecture-Playlist-Snip

CHEM 4380 – Forensic Chemistry

The students appreciated the fall lecture videos so much, there was a great amount of interest in capturing the Forensic Chemistry Lectures. So we created a Forensic Chemistry at Sam Channel, too.

CHEM4380-Playlist-Snip

The lecture playlist is only one piece. Jessy also created other playlists of videos on the Forensic Chemistry at Sam Channel that should interest Forensic Science and Forensic Chemistry students and enthusiasts. She performed these tasks as an SHSU Honors Contract for the course – an activity that supplements the material for the student and enhances the skills that they take away from the course.

Thanks to the Student Team!

Even raw footage must be stitched together, uploaded, described, tagged, and set up on YouTube. This takes TIME and time is a valuable commodity for our chemistry majors.

I thank William Fernandez for videoing CHEM 4448 and CHEM 4449. His videos were so well-received by the students that Jerome Butler decided to sit in and video my Forensic Chemistry course CHEM 4380. Thanks Jerome!

I thank Matthew Peavy for producing the videos for CHEM 4448 and CHEM 4449, and for uploading them. I thank Jessy Stone for producing and uploading the CHEM 4380 videos for Forensic Chemistry.

You students who are willing to go beyond the minimum give us hope for the future.

You people in industry and in graduate programs, hire these students! You won’t be sorry!

-DW

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Posted in Contact Angle, D L Williams, FTIR, Hansen Solubility Parameters, Physical Chemistry, Raman, Solubility, Solvent Blending, Spectroscopy, UV-VIS-NIR, XPS

Corporate Research Funding in Uncertain Times

Some points that describe the current R&D funding climate:

  • Continued uncertainty in corporate R&D hiring
    US non-financial corporate cash holdings rose to $1.24 trillion at the end of 2011 according to Moody’s. One reason among many is a reluctance to hire until the uncertainty surrounding benefits costs is reduced.
  • Tightening of government funding of university R&D
    The US government still funds a significant amount of chemical research, but competition for those funds is increasing greatly. The growing deficit must eventually have an impact on the availability of funds for chemical research.

As a physical chemist, I am partial to APPLIED chemistry research, and the interactions I have had with corporations and government contractors have been enjoyable and fruitful for both parties.

I have prepared this blog post and my new “Sponsors Page” on my university website to actively address the R&D needs of corporations and government contractors.  Many of these entities are under a hiring freeze, and yet, their chemistry-related problems continue unaddressed.

When I worked for a government contractor, I dealt with these issues:

  • “I could solve this problem in 6 months, if I didn’t have to support production, also.”
  • “I’d love to hire someone to research this and other issues but
    1) we are under a hiring freeze,
    2) we don’t have the budget for a whole person (1.0 FTE),
    3) we can afford the salary but are reluctant to commit to an unknown fringe benefit committment,
    4) we can afford a science temp, but we need a Ph.D. chemist.”
  • “Maybe a university researcher could help, but there’s no telling what an Ivory Tower Pinhead is going to spend our money on.  And, what would we have to show for it?”

To quote a recent President, “I feel your pain.”  But not all residents of the Ivory Tower are Pinheads.  Here are the benefits of funding an APPLIED-SCIENCE-MINDED university professor and his students to address your problem.

  • Academic salaries for Ph.D. chemists ($70k, 2012 median) are 65% of that in Industry ($107k, 2012 median) according to the ACS Employment Survey, so renting a brain is potentially cheaper than buying one.  Often these are 9-month salaries, but this annualizes to $93k, which is $14k less than the industry median 12-month salary.
  • Academic chemists are able to spend 100% of their effort on your problem during the summer months.  If the median salary of $70k is for 9-months, then funding this scientist for three full months in the summer is only $23k.  Universities tack on varying amounts of overhead and fringe benefits costs to this number so the actual costs will be more like $40k ($85 / hr all-inclusive).  This is still a very reasonable amount for 3-months of a PhD chemist’s time.
  • Academic institutions have an amazing array of instrumentation that your company could not justify purchasing.  The overhead costs tacked onto the academic chemist’s labor rate is the price of admission to the instrumentation lab or computational facility.  Our lab charges consumables costs on a per-day or per-sample basis in the range of $20.  This may seem to add up, but so do the costs of solvents, vials, etc.
  • Academic institutions are FULL of eager chemistry majors who LOVE to study research problems that are “real life”.  These students are also inexpensive when compared to hourly chemical technicians.  A typical student will have a fully-burdened (with overhead) rate of $20 per hour all-inclusive.  These students will graduate with a working knowlege of your industry and will be excellent prospects for future hires.

The number-one factor to consider is the principal investigator (PI).  Does he or she understand your problem?  Have they done similar work in the past?  I have turned down funding because I did not think I could deliver value to the sponsor.  Find someone who understands your terms, your culture, your requirements, and the practical aspects of implementing the ideas proposed.

If your interests are in any of these areas, I’d love for you to contact me.

  • Cleanliness verification, contact angle measurements, coupon tests
  • Solvent properties, surface tension and hydrostatic densities, Hansen solubility parameters vs Hildebrand solubility parameters
  • Solvent blending, solvent blend prediction, miscibility
  • Solvent substitution, reduction of hazards, reactivity, ozone depletion potential, or global warming potential
  • Material compatibility, polymer stress cracking, polymer swell, polymer processing solvents
  • Recrystallization and crystal morphology control based upon non-solvent interactions
  • High-explosive detection, solubility, modeling, spectroscopy, recrystallization, precipitation, and PBX production/processing
  • Spectral assignments and predictions (FTIR, Raman, UVVIS, XPS)
  • Computational chemistry, ab initio, density functional theory, quantitative structure property relationships (QSPR/QSAR)
  • Six-Sigma Blackbelt – consulting services

There are ways to continue innovating in the current business climate.  I’d love to help if I can.

-Darren

Posted in Hansen Solubility Parameters, Physical Chemistry, Solubility, Solvent Blending

Custom Solvent Blending Using the Hansen Solubility Parameters

I wanted to restore an old metal table that has been sitting outside for more than 30 years. The top is discolored and rusty.  This is a perfect chance to teach the principles of solvent blending using the Hansen Solubility Parameters

This video hits the highlights of the process.  The technical details are available upon request. 

I have a newfound respect for videographers.  This video is pretty rough in places, but I did not have the time nor desire to retake the rough scenes. I promise to provide a more detailed blog post in the future that focuses on the solvent blend optimizer.

Posted in Contact Angle, D L Williams, Hansen Solubility Parameters, Physical Chemistry, Solubility, Solvent Blending

Hansen Solubility Parameters via QSPR

Williams, D. L.; Kuklenz, K. D. A QSAR Model for Predicting Solvents and Solvent Blends for Energetic Materials, Proceedings of the International Annual Conference of ICT, 40th (Energetic Materials), Karlsruhe, Germany, 2/1-2/11, (2009)

Researchers in the paint and polymer industry have shown that the Hansen solubility parameters (HSP) are useful for predicting suitable solvents for the filled-polymer formulation process. To apply this work to the high explosive formulation process, the HSPs of the various energetic materials must be determined or predicted.

A quantitative structure activity relationship (QSAR) was developed that is based upon the output of a density functional theory optimization and frequency calculation (B3LYP/6- 31G(d)//B3LYP/6-31G(d)) using the Gaussian 03 computational package. Structural parameters were extracted from the Gaussian output files of each molecular species. These consisted of the geometric mean of the exact polarizability tensors (α , Å3), the dipole moment (μ, Debye) the highest occupied molecular orbital energy (HOMO, Hartree), the number of each type of atom, and the delta charge (Δq) – defined as the difference between the most negative heteroatom and the most positive hydrogen in the molecule. The value of Δq = 0 was given to hydrocarbons by fiat. A stepwise linear regression was used to determine the correlation of these inputs and mathematical transformations of these inputs to the HSPs for a training set of 54 solvents and nitrated compounds. The resulting QSAR matrix was then applied to 23 energetic materials and precursors yielding the HSPs (δD, δP, δH) in MPa1/2.

The HSPs were also determined for HMX, RDX, PETN, and HNS using experimental solubility data and the group additivity methods of Van Krevelen and Stefanis. The QSAR model outperformed the group additivity methods in matching the experimentally determined HSPs using the Hansen distance parameter (Ra) as the figure of merit.

En route to the QSAR model, a very simple model of molar volume was developed wherein the molar volume is computed directly from the molecular formula CaHbNcOdSePfFgClhBri via the following equation: Vm = 12.53 + 8.77a + 3.96b + 4.87c + 6.12d + 17.22e + 19.45f + 9.70g + 18.66h + 20.74i. The correlation of this equation with the literature values of 183 molecules was 99.67% with an R2 = 0.9847 over a range of 400 cm3/mol.

Posted in Contact Angle, D L Williams, Hansen Solubility Parameters, Solubility

Solubility Spheres

When working with industrial scale recrystallizations, a few more grams per liter improvement in solubility can save a substantial amount of time and MONEY. 

Williams, D. L.; Kuklenz, K. D., A Determination of the Hansen Solubility Parameters of Hexanitrostilbene (HNS), Propellants Explosives and Pyrotechnics, 34(5), 452-457, (2009) 

Abstract
The temperature-dependent solubility of hexanitrostilbene (HNS) [CAS# 20062-22-0] was determined in ten solvents and solvent blends using the Tyndall effect. Thermodynamic modeling of the data yielded Flory interaction parameters, the molar enthalpy of mixing, the molar entropy of mixing, and the molar Gibbs energy of mixing. All solutions exhibited endothermic enthalpies and positive entropies of mixing. The presence of water in some of the solvent blends made dissolution increasingly endothermic and disfavored solubility. The solubilities of HNS at 25 °C were used to determine the three-component Hansen solubility parameters (HSP) (δD=18.6, δP=13.5, δH=6.1 MPa1/2) and the radius of the solubility sphere (R0=5.8 MPa1/2). The HSP determined for HNS using group-additivity (δD=21.0, δP=13.3, and δH=8.6 MPa1/2) also correctly predicted the optimum solvents for this explosive.