Solvent effects on chemical reaction

A solvent can be any substance, that turns into a solution by dissolving a solid, liquid, or gaseous solute. The solvent is usually a liquid, but can also be a solid or gas.

In our daily life, we will find the best example of solvent, that is none other than water.

Solvent’s common uses ranges from dry cleaning agents, paint thinners, nail polish removers, glues, spot removers, detergents and in personal care products like perfumes

Examples of solvents

Toluene

Acetone

Methyl acetate

Hexane

Ethanol

Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syntheses and purification processes.

Most other commonly-used solvents are carbon-containing chemicals. These are termed as organic solvents.Solvents usually have a low boiling point and as a result, they will evaporate easily or can be removed by a various simple process called distillation, thereby leaving the dissolved substance behind.Solvents are inert nature, as they will not react chemically with the dissolved compounds. These can also be used to extract soluble compounds from a mixture, the most common example is the brewing of coffee or tea with hot water.

Solvent classifications

The solvents are basically grouped into non-polar, polar aprotic, and polar protic solvents.

Solvent effects on chemical reaction

Solvents can have an effect on various properties of substances like solubility, stability and reaction rates

Solvents effects on solubility

A solute dissolves in a solvent only when it forms favourable interactions with the solvent. This dissolving process all depends upon the free energy change of both solute and solvent. This in turn free energy of solvation is again depended upon several factors.

Solvents effects on stability

Different solvents can affect the equilibrium constant of a reaction by differential stabilisation of the reactant or product. The equilibrium is shifted in the direction of the substance that is preferentially stabilised. Stabilisation of the reactant or product can occur through any of the different non-covalent interactions with the solvent such as H-bonding, dipole-dipole interactions, van der waals interactions etc.

In another instance, the ionisation equilibrium of an acid or a base is affected by a solvent change. The effect of the solvent is not only because of its acidity or basicity but also because of its dielectric constant and its ability to preferentially solvate and thus stabilise certain species in acid-base equilibria. A change in the solvating ability or dielectric constant can thus influence the acidity or basicity.

Solvents effects on reaction rates

Solvents can affect rates through equilibrium-solvent effects that can be explained on the basis of the transition state theory. In essence, the reaction rates are influenced by differential solvation of the starting material and transition state by the solvent. 

Other effects of solvents

The solvent used in substitution reactions inherently determines the nucleophilicity of the nucleophile. As such, solvent conditions significantly affect the performance of a reaction with certain solvent conditions favouring one reaction mechanism over another. For SN1 reactions the solvent's ability to stabilise the intermediate carbocation is of direct importance to its viability as a suitable solvent. The ability of polar solvents to increase the rate of SN1 reactions is a result of the polar solvent's solvating the reactant intermediate species, i.e., the carbocation, thereby decreasing the intermediate energy relative to the starting material.

SN1 reactions

The SN1 reaction is a substitution reaction in organic chemistry. ‘SN’ stands for nucleophilic substitution and the ‘1’ represents the fact that the rate-determining step is unimolecular. The reaction involves a carbocation intermediate and is commonly seen in reactions of secondary or tertiary alkyl halides under strongly basic conditions or, under strongly acidic conditions, with secondary or tertiary alcohols.

SN2 reactions

The SN2 reaction is a type of reaction mechanism that is common in organic chemistry. In this mechanism, one bond is broken and one bond is formed synchronously. SN2 is a kind of nucleophilic substitution reaction mechanism.

The case for SN2 reactions is quite different, as the lack of solvation on the nucleophile increases the rate of an SN2 reaction.

The reactions involving charged transition metal complexes (cationic or anionic) are dramatically influenced by solvation, especially in the polar media.

© WOC Article

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Fluor bags maintenance contract by SunCoke Energy

IRVING, US: Fluor Corporation has been awarded a maintenance support and capital project services contract by SunCoke Energy Inc, for its coke facilities in US.

Under the five-year contract, Fluor will provide maintenance and capital project services at SunCoke’s US domestic coke facilities, which produce high-quality coke for use in steelmaking. Fluor will transition onto the sites in early March 2017 and work alongside SunCoke employees.

“With a detailed transition plan, we are partnering with SunCoke on a seamless transition to the sites with no disruption to current operations. We will implement our asset performance management process and identify specific opportunities to reduce SunCoke’s total ownership costs,” said Dale Barnard, VP of North American maintenance, modification and asset integrity operations for Fluor.

© Worldofchemicals News 

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AkzoNobel adds colour to the new McLaren-Honda Formula 1 car

AMSTERDAM, NETHERLANDS: The 2017 McLaren-Honda Formula 1 racing car, MCL32 was launched with AkzoNobel’s new Tarocco Orange livery – a colour developed by AkzoNobel in conjunction with McLaren-Honda.

The company’s colour expertise has enabled the world championship winning Formula 1 team to maintain links to their 1960s roots and heritage while bringing a new image and sparkle. The new Tarocco Orange colour provided a striking contrast to matt black and gloss white finish.

The two companies have been working closely together since 2008 when AkzoNobel first became an official supplier of paint solutions to the McLaren-Honda Formula 1 team. McLaren-Honda will use the company’s premium Sikkens brand for its Formula 1 cars for the whole of the 2017 season, which starts in Melbourne, Australia, on 26 March.

“Our colour and coatings expertise shows up in many unexpected places, even in Formula 1. We share a passion with McLaren for creating efficient, high-performance technology. McLaren-Honda Formula 1 team is known for their iconic livery and the new colour will add a new chapter to this, which we are proud to be part of” said Peter Tomlinson, managing director of AkzoNobel’s vehicle refinishes business.

“Since McLaren began its partnership with AkzoNobel, we’ve always been looking at ways to push paint technology to its furthest extent. We’ve already explored the practical limits of chrome finishing, reducing our carbon footprint and reducing curing times. Now, with the McLaren-Honda MCL32, we’re really leveraging AkzoNobel’s colour expertise and technology. The results are stunning,” added Jonathan Neale, COO of McLaren Technology Group.

“We’ve also made significant progress in reducing the average curing time of bodywork parts by more than half and lowering the paint shop’s carbon footprint by up to 80 percent. We will continue working with AkzoNobel on further innovations as we investigate coating possibilities, both for now and for the future,” he concluded.

© Worldofchemicals News 

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Accella to acquire spray polyurethane foam biz from Covestro

ST LOUIS, US: Accella Polyurethane Systems LLC, a unit of Arsenal Capital Partner has agreed to buy certain assets of the North American spray polyurethane foam (SPF) business from Covestro LLC. The sale is scheduled to be completed in the second quarter of 2017.

The Covestro Spring, TX  facility includes both commercial and production operations, serving North America as a leading producer of spray polyurethane foam, which is used as insulation and roofing in the construction of commercial buildings and residential homes. The roughly 40 Covestro employees at the Spring facility will make a great fit with the Accella team. Operations will continue at the current facility with "business as usual" for a smooth transition for all customers.

"This acquisition will significantly improve Accella's position in the spray polyurethane foam market and is another strategic step with our positive track record combining the best polyurethane based companies in the industry. The addition of a well-rounded product technology portfolio and a team of highly regarded industry experts will highly complement our current spray polyurethane foam business," said Andy Harris, president and CEO of Accella.

"SPF is a very important area of business for our company with the value it brings to society. We will continue to raise the position of SPF as the preferred insulation choice in modern residential and commercial construction," added Chris Brink, Accella's VP of polyurethane systems.

"The accomplishments of Covestro's spray polyurethane foam team cannot be overstated. Both technically and commercially, their contributions have helped grow spray polyurethane foam as a technology in the construction market. This divestiture will allow us to focus on our core business while ensuring our spray polyurethane foam employees can continue to shape the industry as a part of Accella," concluded Jerry MacCleary, president of Covestro LLC.

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Kirloskar showcased pump solutions for textile industry

PUNE, INDIA: Kirloskar Brothers Limited (KBL) has showcased its range of pumps for the textile industry recently in Dhaka, Bangladesh.

KBL presented its extensive expertise in fluid management solutions for various applications in textile processing and offers a wide range of high-quality process & utility pumps for this industry. KBL offers complete end-to-end pump solutions for various processes in the textile industry, such as intake, utility, effluent treatment, boiler feed and fire-fighting. In the textile industry, water is majorly consumed during chemical (wet) processing of textiles, steam generation, humidification (spinning process) & other utility purposes as well as in water treatment plants and cooling towers. Optimum utilisation of water and available energy resources holds prime importance in this industry.

KBL’s range of pumps include:

• Hydro-Pneumatic (HYPN) system
• DB pump
• UP pumps
• bore well submersible pump KS9C 3003 (CI Casing)

Among these, HYPN is a pressure boosting conventional pumping system converted into an automated pumping system, which ensures energy and cost savings. DB and UP pumps are predominantly used for intake and utility applications in the textile industry. Bore well submersible pump KS9C 3003 (CI Casing) holds a capacity of pumping up to 3000 litres per minute. KS9 submersible pumps are suitable for pumping high volumes of water.   

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Oil & gas, energy and chemicals outlook in 2017

By Uday Turaga

For the year 2017, the oil & gas, energy and chemical industries must grapple with an uncertainty that stems from various factors including the OPEC deal, Donald Trump’s election, Brexit, slowing emerging economies, electric vehicles, and new regulations. The ADI team has assessed these factors and uncertainties in our outlook for 2017.

Upstream - Oil

• Oil prices have recovered following the OPEC deal – that Russia has joined too – to cut output although it’s too early to say if the deal’s contribution is pure sentiment or an actual price floor. Uncertainty around compliance with the deal will continue to foster anxiety especially since OPEC nations had elevated productions, to begin with.

• Rising oil prices will encourage shale operators to bring uncompleted and, potentially, new wells online – with lower costs and higher productivity – and the North American resource is increasingly likely to serve as a price ceiling.

• Credit, which was financing capital spending for upstream independents and dividends for majors, is drying up. So, oil and gas players relied on divestments for cash flow and were supported by inflated acreage valuations particularly in the Permian and Appalachia M&A deals last year.

• Oil demand growth is slowing in the medium term thanks to rising fuel economy of automobiles, growing penetration of electric and autonomous vehicles, declining role of energy-intensive manufacturing in emerging economies, and demographic shifts away from car ownership. In the near term, oil demand growth is fragmenting as large emerging economies are slowing while smaller emerging economies are surging.

• President-Elect Donald Trump’s promise to cut regulations has little policy detail but will support the positive industry sentiment.

Upstream - Natural Gas

• The global natural gas resource base continues to be robust but supply is likely to moderate with North America likely to finally cut natural gas production in 2017. Even so, LNG production is likely to grow further with new trains coming online in 2017 at Gorgon, Ichthys, Wheatstone, and Sabine Pass.

• Natural gas exports to Mexico, cold weather prospects, growing share of gas-fired power generation, and rising LNG exports are all likely to strengthen natural gas demand although it is not growing fast enough relative to supply.

• Slowing supply and rising demand are more likely than seen in the recent past to strengthen natural gas prices although there is considerable uncertainty.

• LNG markets are struggling with oversupply leading to a renewed push among large buyers, e.g., Japan and South Korea, to weaken oil price indexation. Japan is liberalising its LNG purchasing policies, Singapore is positioning itself as a regional hub, and India is actively trading LNG cargoes thereby increasing supply liquidity in the Asian market. In Europe, pipeline gas suppliers have reacted to protect market share in the wake of abundant LNG supply.

• Technology development and innovation around natural gas production and utilisation continue to advance rapidly. In 2017, shale breakeven costs are likely to drop further, Petronas is closing in on shipping the first cargo ever from a floating LNG unit, and FSRU adoption is growing quickly.

Midstream and Natural Gas Liquids

• Natural gas liquids (NGL) production grew at a slower pace in 2016 as lower prices impacted drilling across the board.

• In 2017 (and 2018), ethane and LPG exports will continue but half a dozen ethylene crackers will also be commissioned driving up demand for ethane well beyond likely supply (including ethane that is currently being rejected) leading chemical producers to other cracking feedstocks, e.g., propane, butane, natural gasoline, and naphtha.

• Thus, NGL pricing may pick up and the frac spread will likely widen. However, improved pricing is unlikely to spawn a whole lot of new capital investment given that midstream players are struggling with surplus capacity.

• Consolidation will likely move past the false starts in 2016 and intensify in 2017 as players struggle with overcapacity and contract abrogations and renegotiations, and capital supply improves for top-tier performers.

Downstream, Refining, and Fuels

• Refining margins around the world declined dramatically in 2016. S. crack spreads fell due to lower product prices in export markets and higher crude oil prices relative to Brent while Asia and Europe were oversupplied from capacity and exports.

• Companies that had built exposure to midstream and trading capabilities performed better than pure-play peers and will continue to be advantaged in 2017.

• Consolidation among the pure-play refiners is likely to continue in 2017 and international participation in the U.S. downstream segment will likely increase too.

• Fuel regulations around sulphur limits, rising octane barrel values, crude oil and refined product exports, and pricing challenges with renewable identification numbers will occupy industry players in 2017.

Oilfield Services and Energy Equipment Markets

• Upstream capex declined a little over 20% in 2016 better than the cuts exceeding 25% in 2015. Led by North American and national oil companies, upstream capex will rise by about 5% in 2017.

• In addition, oil and gas operators are clamping down on costs frustrated by the industry’s rising capital intensity. Since 2008, oil and gas capex growth has exceeded 6% but production has grown only 2% annually.

• Capital spending will be allocated to smaller and near-term projects and it will likely be several years before operators will consider new deepwater, oil sands, large-scale LNG, and refining projects

• In such an environment of depressed capital spending, the share of aftermarket services in the oil and gas equipment market will continue to rise.

• Mergers and acquisitions, which intensified in 2016 with Technip-FMC Technology and the GE-Baker Hughes deals being prominent examples, will likely continue in 2017 as players struggle with depressed capex and pricing flexibility.

• Oilfield service companies and OEMs may see some revenue growth in 2017 mainly driven by new business activity and not from higher prices.

Power

• President-Elect Trump’s policies may address the power sector but are anticipated to have limited impact driven mainly by costs and economics. Thanks to the shale revolution, natural gas-fired power generation is more competitive especially when uncertainties around coal in the long-term are considered. In the case of renewables, states’ renewable portfolio standards and continued production and investment tax credits will support new capacity additions.

• New infrastructure spending – if approved by the Congress – may, however, drive significant new investment in modernising the grid and upgrading transmission and distribution infrastructure.

• Energy storage costs are falling and the technology is advancing rapidly. Its adoption will grow at a faster pace in 2017 driven by both operational and business model innovations supporting power generation from both natural gas and renewables.

• “Clean coal” may make a comeback driven by President-Elect Trump’s promise to coal workers although its impact may be limited.

Chemicals

• Economic strife in China, overcapacity and weak private investment significantly hindered global chemical industry growth in 2016.

• An emerging light vehicle market, positive trends in construction, and significant shale-linked capital investment is expected to spurn a recovery in 2017.

• In 2017, chemical players will shift their focus to high-growth emerging markets and segments, e.g., automotive and housing, to reduce exposure to businesses that are struggling with depressed demand.

• Further consolidation is expected to happen in 2017 as there is still a difficult economic climate and chemical manufacturers are seeking opportunities to increase operational scale and optimise cost.

Author: Uday Turaga is CEO of ADI Analytics LLC.

© Chemical Today News

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Albemarle, Tianqi terminate share purchase

CHARLOTTE, US: Albemarle Corporation and Tianqi Lithium Corporation (Tianqi) have entered into a deed of termination, pursuant to which Tianqi's exercise of a previously announced option to acquire a 20 percent indirect ownership interest in Rockwood Lithium GmbH and its subsidiaries has been terminated.

In accordance with the deed of termination, the option agreement has been terminated and the exercise of the option by Tianqi will cease to have any legal effect.

© Worldofchemicals News 

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New research advances energy savings for oil, gas industries

PULLMAN, US: A research team from Washington State University (WSU) has improved an important catalytic reaction commonly used in the oil and gas industries that could lead to dramatic energy savings and reduced pollution.

They report on their work is published in the journal Angewandte Chemie, which has designated the paper of particular interest and importance. The research is led by Jean-Sabin McEwen, assistant professor, and Su Ha, associate professor, of the Gene and Linda Voiland School of Chemical Engineering and Bioengineering at WSU.

Efficiently converting methane

Methane gas is a byproduct in much of the oil and gas industry, where it may build up during operations and cause a safety concern.

Methane also is a primary ingredient in natural gas used to heat homes, and it can be converted into many useful products including electricity. But breaking the strong bond between its carbon and hydrogen takes a tremendous amount of energy.

“It’s a very happy molecule. t does not want to break apart,” said McEwen.

To convert methane, the oil and gas industry most often uses a nickel-based catalyst. But it is often less expensive to simply burn the methane in giant flares on site; however, this adds greenhouse gases to the atmosphere, contributing to global warming, and wastes energy. In the US, for example, the amount of methane burned annually is as much as 25 percent of the country’s natural gas consumption.

“Right now, we just waste all those gases,” said Ha. “If we can efficiently and effectively convert methane from shale or gas fields to electric power or useful products, that would be very positive.”

Nickel carbide an effective catalyst

The researchers determined that they can dramatically reduce the energy needed to break the bond between carbon and hydrogen by adding a tiny bit of carbon within the nickel-based catalyst. This creates nickel carbide, which generates a positive electrical field. This novel catalyst weakens the methane molecule’s hydrogen-carbon bond, allowing it to break at much lower temperatures.

The researchers found that while too much carbon in the catalyst kills the reaction, a very low concentration actually enhances it. They have built a numerical model of the reaction and are working to show the work experimentally.

“It’s exciting to be conducting research in which experimentalists and computational researchers are working side by side to advance the field,” said Ha. “This needs to be done more often in the sciences for the development of these breakthrough technologies.”

The work was funded by the American Chemical Society’s Petroleum Research Fund with computational support from Argonne National Laboratory.

© Washington State University News 

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New technology offers fast peptide synthesis

MASSACHUSETTS, US: Manufacturing small proteins known as peptides is usually very time-consuming, which has slowed development of new peptide drugs for diseases such as cancer, diabetes, and bacterial infections.

To help speed up the manufacturing process, Massachusetts Institute of Technology (MIT) researchers have designed a machine that can rapidly produce large quantities of customised peptides. Their new tabletop machine can form links between amino acids, the buildings blocks of proteins, in about 37 seconds, and it takes less than an hour to generate complete peptide molecules containing up to 60 amino acids.

“You can dial in whatever amino acids you want, and the machine starts printing off these peptides faster than any machine in the world,” said Bradley Pentelute, associate professor of chemistry at MIT and senior author of a paper.

The research is published in the journal Nature Chemical Biology.

This technology could help researchers rapidly generate new peptide drugs to test on a variety of diseases, and it also raises the possibility of easily producing customised cancer vaccines for individual patients.

The paper’s lead authors are graduate students Alexander Mijalis and Dale Thomas; other authors are graduate student Mark Simon, research associate Andrea Adamo, Ryan Beaumont, and Warren Lewis professor of chemical engineering Klavs Jensen.

Fast flow

Using traditional peptide manufacturing techniques, which were developed more than 20 years ago, it takes about an hour to perform the chemical reactions needed to add each amino acid to a peptide chain.

Pentelute, Jensen, and their colleagues set out several years ago, to devise a faster method based on a newer manufacturing approach known as flow chemistry. Under this strategy, chemicals flow through a series of modules that each perform one step of the overall synthesis.

The team’s first version of a flow-based peptide synthesis machine, reported in 2014, sped up the process to about three minutes per peptide bond. In their latest effort, the researchers hoped to make the synthesis even faster by automating more of the process. In the earlier version, the person running the machine had to manually pump amino acids out of their storage bottles, but the new machine automates that step as well.

“Our focus when we were setting out to design the automated machine was to have all the steps controlled by a computer, and that would eliminate a lot of the human error and unreliability that’s associated with someone doing this process by hand,” Mijalis said.

Once a user enters the desired amino acid sequence, the amino acids are pumped, in the correct order, into a module where they are briefly heated to about 90 degrees Celsius to make them more chemically reactive. After being activated, the amino acids flow into a chamber where they are added to the growing peptide chains.

As each amino acid is added to the chain, the researchers can measure how much was correctly incorporated by analysing the waste products that flow into the final chamber of the device. The current machine attaches each amino acid to the chain with about 99 percent efficiency.

Personalised chemistry

Once synthesised, small peptides can be joined together to form larger proteins. So far, the researchers have made proteins produced by HIV, a fragment of an antifreeze protein (which helps organisms survive extreme cold), and a toxin secreted by snails. They are also working on replicating toxins from other animals, which have potential uses as painkillers, blood thinners, or blood clotting agents. They have also made antimicrobial peptides; which scientists are exploring as a possible new class of antibiotic drugs.

Another possible application for the new machine is generating peptides that could be used as personalised cancer vaccines targeting unique proteins found in individual patients’ tumours. “That’s exactly what our machine makes, and it makes them at scales that are all ready to meet this demand for personalised cancer vaccines,” Pentelute added.

The MIT team is also interested in adapting this technology to make other molecules in which building blocks are strung together in long chains, such as polymers and oligonucleotides (strands of RNA or DNA).

© MIT News

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Researchers improve graphene DNA-detecting transistors

TSUKUBA, JAPAN: Researchers in India and Japan have developed an improved method for using graphene-based transistors to detect disease-causing genes.

Graphene field-effect transistors (GFETs) can detect harmful genes through DNA hybridization, which occurs when a 'probe DNA' combines, or hybridises, with its complementary 'target DNA.' Electrical conduction changes in the transistor when hybridization occurs.

Nobutaka Hanagata of Japan's National Institute for Materials Science and colleagues improved the sensors by attaching the probe DNA to the transistor through a drying process. This eliminated the need for a costly and time-consuming addition of 'linker' nucleotide sequences, which have been commonly used to attach probes to transistors.

The research is published in the journal Science and Technology of Advanced Materials.

The research team designed GFETs that consist of titanium-gold electrodes on graphene - a one-atom-thick layer of carbon - deposited on a silicon substrate. Then they deposited the DNA probe, in a saline solution, onto the GFET and left it to dry. They found that this drying process led to direct immobilisation of the probe DNA on the graphene surface without a need for linkers. The target DNA, also in saline solution, was then added to the transistor and incubated for four hours for hybridization to occur.

The GFET operated successfully using this preparation method. A change in electrical conduction was detected when the probe and target combined, signalling the presence of a harmful target gene. Conduction did not change when another non-complementary DNA was applied.

DNA hybridization is usually detected by labelling the target with a fluorescent dye, which shines brightly when it combines with its probe. But this method involves a complicated labelling procedure and needs an expensive laser scanner to detect fluorescence intensity. GFETs could become a cheaper, easier to operate, and more sensitive alternative for detecting genetic diseases.

"Further development of this GFET device could be explored with enhanced performance for future biosensor applications, particularly in the detection of genetic diseases," conclude the researchers.

© Chemical Today News

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