Thursday, January 18, 2018

Top Five Chemistry Inventions: Avenue for Modern World

Chemistry, well-known as the central science, a creative tributary of science involves the study of the composition, structure, and properties of matter. There are numerous inventions till this date in chemistry and this exercise will not end until the last day of the earth! Actually, Chemistry is the vital part of every living creatures. What they eat to what they wear is the boon of chemistry. Yet, it turns out that most people just don’t have a good idea of what chemists do, or how chemistry contributes to the modern world. Few people know that the discovery of ammonia was the single most important reason for the world’s population explosion from 1.6 billion in 1900 to 7 billion today! Or that polythene, the world’s most common plastic, was accidentally invented twice!
Here, I will reveal, in chronological order, the most significant discoveries made so far that changed the lifestyle of human beings.
                    1. The Haber-Bosch Process of Synthesis of Ammonia
Fritz Haber and Carl Bosch
Picture from Google
Nitrogen the most common gas in our atmosphere and plays a critical role in the biochemistry of every living thing. But plants and animals can’t extract it from the air as this gas doesn’t like reacting with very much. Consequently, a major limiting factor in agriculture has been the availability of nitrogen. In 1910, German chemists Fritz Haber and Carl Bosch changed all this when they combined atmospheric nitrogen and hydrogen into ammonia. This, in turn, can be used as crop fertilizer, eventually filtering up the food chain to us. Today about 80% of the nitrogen in our bodies comes from the Haber-Bosch process, making this single chemical reaction probably the most important factor in the population explosion of the past 100 years.

                   2. Discovery of Penicillin
Before the discovery of antibiotics, a prick from a thorn or a sore throat could have easily turned fatal. In 1928, Alexander Fleming observed how a mold growing on his Petri dishes suppressed the growth of nearby bacteria. But he failed to extract any usable penicillin. In 1939, Australian pharmacologist Howard Florey and his team of chemists figured out a way of purifying penicillin in usable quantities.

Alexander Fleming
Picture from Google
As World War II was raging at this time, scientific equipment was in short supply. There were thousands of wounded military persons and common people seeking a medicine to cure their wounds. Thank God! penicillin saved their life. By seeing the miracle of penicillin, the team cobbled together a totally functional penicillin production plant from bathtubs, milk churns and bookshelves. Not surprisingly the media were extremely excited about this new wonder drug, but Florey and his colleagues were rather shy of publicity. Instead, Fleming took the limelight.

Full-scale production of penicillin took off in 1944 when the chemical engineer Margaret Hutchinson Rousseau took Florey’s Heath Robinson-esque design and converted it into a full-scale production plant.

            3Discovery of Progesterone
In the 1930s, physicians had realized the potential use of hormone-based therapies to treat cancers, menstrual disorders and of course, for contraception. But research and treatments were held back by massively time-consuming and inefficient methods for synthesizing hormones.

Back then progesterone cost the equivalent (in today’s prices) of $1,000 per gram while now the same amount can be bought for just a few dollars. Russel Marker, a professor of organic chemistry at Pennsylvania State University, slashed the costs of producing progesterone by discovering a simple shortcut in the synthetic pathway. He went scavenging for plants with progesterone-like molecules and stumbled upon a Mexican yam. From this root vegetable, he isolated a compound that took one simple step to convert into progesterone for the first contraceptive pill.

               4. Discovery of Polyethylene - the common plastic
Polyethylene or polythene is the most common plastic. The annual global production is around 80 million tonnes. Its primary use is in packaging. Most common plastic objects, from water pipes to food packaging and hardhats, are forms of polythene. The 80 million tones of the stuff that is made each year is the result of two accidental discoveries.

Hans von Pechmann
Picture from Google
The first occurred in 1898 when German chemist Hans von Pechmann, while investigating something quite different, noticed a waxy substance at the bottom of his tubes. Along with his colleagues, he investigated and discovered that it was made up of very long molecular chains which they termed polymethylene. The method they used to make their plastic wasn’t particularly practical, so much like the penicillin story, no progress was made for some considerable time.

Then in 1933, an entirely different method for making the plastic was discovered by chemists at, the now defunct chemical company, ICI. They were working on high-pressure reactions and noticed the same waxy substance as von Pechmann. At first, they failed to reproduce the effect until they noticed that in the original reaction oxygen had leaked into the system. Two years later ICI had turned this serendipitous discovery into a practical method for producing the common plastic that’s almost certainly within easy reach of you now.


                5. The Discovery of Liquid Crystal - the screen you are reading on
Liquid crystal
Plans for a flat-screen color display date back to late 1960  when the British Ministry of Defense decided that it wanted flat-screens to replace bulky and expensive cathode ray tubes in its military vehicles. It settled on an idea based on liquid crystals. It was already known that liquid crystal displays (LCDs) were possible, the problem was that they only really worked at high temperatures. So not much good unless you are sitting in an oven.

Phone Screen uses liquid crystal
In 1970 the MoD commissioned George Gray at the University of Hull to work on a way to make LCDs function at more pleasant (and useful) temperatures. He did just that when he invented a molecule known as 5CB. By the late 1970s and early 1980s, 90% of the LCD devices in the world contained 5CB and you’ll still find it in the likes of cheap watches and calculator. Meanwhile, derivates of 5CB make the phones, computers, and TVs possible.

1. The Conversation Edition, June 1, 2015
2., January 18, 2018

Monday, September 18, 2017

8th ASCASS Conference in Kathmandu, Nepal

Asian Society for Colloid and Surface Science, ASCASS, established on 2004, is going to organize its 8th conference in Kathmandu, Nepal on September 25-28, 2019. Earlier, ASCASS organized its 7th Asian Conference on Colloid and Interface Science on 8-11 August 2017 in Berjaya Times Square Hotel, Kuala Lumpur, MALAYSIA.  The current president of ASCASS is Professor Toyoko Imae from National Taiwan University, Taiwan.

It is a matter of pride to all Nepalese that an important conference is going to be held in Kathmandu. The blogger likes to thank Dr. Lok Kumar Shrestha, a preeminent Nepali researcher (currently in National Institute for Materials Science, Japan), for his great effort as a key role player in attracting such conference in Nepal. For sure, this conference will entice many researchers in the beautiful city of Kathmandu which will ultimately help in substantial discussions in the field of Colloids and Interface Science. There is no question that the tourism industry in Nepal will flourish. 

Friday, July 28, 2017

New Imaging Technique in Surface Chemistry

As being a surface chemist, I keep on tracking the signs of progress made so far in the Surface Chemistry field. Recently, I found good news about the imaging tool in surface chemistry. Here is the story:
Researchers at Ecole Polytechnique Fédérale de Lausanne (EPFL) Laboratory for Fundamental BioPhotonics (LBP) have developed a microscope that can track, in real time, 3D spatial changes in the molecular structure and chemistry of confined systems, such as curved surfaces and pores to understand the geological, catalytic, biological and chemical processes which are driven by surface chemical heterogeneities, electrostatic fields and flow. They predict that this may enable the further development of new materials and microtechnology.
“An optical imaging tool to visualize surface chemistry in real time has been developed. This system basically images the interfacial chemistry in the microscopically confined geometry of a simple glass micro-capillary. The glass is covered with hydroxyl (-OH) groups that can lose a proton, a much-studied chemical reaction that is important in geology, chemistry, and technology. A 100-micron long capillary displayed a remarkable spread in surface OH bond dissociation constant of a factor of a billion.”
The developed microscope was used to image the surface chemical structure of the inside of a glass microcapillary. Surface potential maps were designed from the millisecond images, and the chemical reaction constant of each 188nm-wide pixel was evaluated. Amazingly, this very simple system which is used in many devices displayed a stunning spread in surface heterogeneity. The researchers' findings have been published in Science. It is believed that this method will be a plus point in understanding fundamental (electro)chemical, geological and catalytic processes and for building new devices.
Second-harmonic imaging
Imaging of surface potential and chemical process at the surface.
Image: taken from Google (28th July, 2017)
Sylvie Roke, director of the Julia Jacobi Chair of Photomedicine at EPFL, has developed a unique set of optical tools to study water and aqueous interfaces on the nanoscale. She uses second-harmonic and sum-frequency generation, which are optical processes in which two photons of a certain color are converted into a new color. "The second-harmonic process involves 1000 nm femtosecond photons i.e., 0.00000000000001-second bursts of light -- being converted into 500 nm photons, and this occurs only at interfaces," says Roke. "It is therefore ideal for interfacial microscopy. Unfortunately, the process is very inefficient. But by using a number of optical tricks, such as wide field imaging and light shaping, we were able to enhance both the imaging throughput and the resolution, bringing the time to record an image down from minutes to 250 milliseconds."
Surprising surface chemistry
The researchers then imaged the deprotonation reaction of the inner silica capillary/water interface in real time. Silica is one of the most abundant minerals on earth, and its interaction with water shapes our climate and environment. Although many researchers have characterized the properties of the silica/water interface, there is no consensus on its chemical reactivity. Roke continues: "Our data shows why there is a remarkable spread in surface reactivity, even on a very small portion of a capillary. Our data will help in the development of theoretical models that are more effective at capturing this surprising complexity. In addition, our imaging method can be used for a wide variety of processes, such as for analyzing the real-time functioning of a fuel cell, or for seeing which structural facet of a mineral is most chemically active. We could also gain more insight into nanochannels and both artificial and natural pores.
 1. Carlos Macias-Romero, Igor Nahalka, Halil I. Okur, Sylvie Roke. Optical imaging of surface chemistry and dynamics in confinementScience, July 2017 DOI: 10.1126/science.aal4346
2. Science Daily, July 28, 2017 Issue (