Tag Archives: acetic acid

Preserving heritage smells (scents)

Preserving a smell? It’s an intriguing idea and forms the research focus for scientists at the University College London’s (UCL) Institute for Sustainable Heritage according to an April 6, 2017 Biomed Central news release on EurekAlert,

A ‘Historic Book Odour Wheel’ which has been developed to document and archive the aroma associated with old books, is being presented in a study in the open access journal Heritage Science. Researchers at UCL Institute for Sustainable Heritage created the wheel as part of an experiment in which they asked visitors to St Paul’s Cathedral’s Dean and Chapter library in London to characterize its smell.

The visitors most frequently described the aroma of the library as ‘woody’ (selected by 100% of the visitors who were asked), followed by ‘smoky’ (86%), ‘earthy'(71%) and ‘vanilla’ (41%). The intensity of the smells was assessed as between ‘strong odor’ and ‘very strong odor’. Over 70% of the visitors described the smell as pleasant, 14% as ‘mildly pleasant’ and 14% as ‘neutral’.

In a separate experiment, the researchers presented visitors to the Birmingham Museum and Art Gallery with an unlabelled historic book smell – sampled from a 1928 book they obtained from a second-hand bookshop in London – and collected the terms used to describe the smell. The word ‘chocolate’ – or variations such as ‘cocoa’ or ‘chocolatey’ – was used most often, followed by ‘coffee’, ‘old’, ‘wood’ and ‘burnt’. Participants also mentioned smells including ‘fish’, ‘body odour’, ‘rotten socks’ and ‘mothballs’.

Cecilia Bembibre, heritage scientist at UCL and corresponding author of the study said: “Our odour wheel provides an example of how scientists and historians could begin to identify, analyze and document smells that have cultural significance, such as the aroma of old books in historic libraries. The role of smells in how we perceive heritage has not been systematically explored until now.”

Attempting to answer the question of whether certain smells could be considered part of our cultural heritage and if so how they could be identified, protected and conserved, the researchers also conducted a chemical analysis of volatile organic compounds (VOCs) which they sampled from books in the library. VOCs are chemicals that evaporate at low temperatures, many of which can be perceived as scents or odors.

Combining their findings from the VOC analysis with the visitors’ characterizations, the authors created their Historic Book Odour wheel, which shows the chemical description of a smell (such as acetic acid) together with the sensory descriptions provided by the visitors (such as ‘vinegar’).

Cecilia Bembibre said: “By documenting the words used by the visitors to describe a heritage smell, our study opens a discussion about developing a vocabulary to identify aromas that have cultural meaning and significance.”

She added: “The Historic Book Odour Wheel also has the potential to be used as a diagnostic tool by conservators, informing on the condition of an object, for example its state of decay, through its olfactory profile.”

The authors suggest that, in addition to its use for the identification and conservation of smells, the Historic Book Odour Wheel could potentially be used to recreate smells and aid the design of olfactory experiences in museums, allowing visitors to form a personal connection with exhibits by allowing them to understand what the past smelled like.

Before this can be done, further research is needed to build on the preliminary findings in this study to allow them to inform and benefit heritage management, conservation, visitor experience design and heritage policy making.

Here’s what the Historic Book Odour Wheel looks like,

Odour wheel of historic book containing general aroma categories, sensory descriptors and chemical information on the smells as sampled (colours are arbitrary) Courtesy: Heritage Science [downloaded from https://heritagesciencejournal.springeropen.com/articles/10.1186/s40494-016-0114-1

Here’s a link to and a citation for the paper,

Smell of heritage: a framework for the identification, analysis and archival of historic odours by Cecilia Bembibre and Matija Strlič. Heritage Science20175:2 DOI: 10.1186/s40494-016-0114-1 Published: 7 April 2017

©  The Author(s) 2017

This paper is open access.

Gold, acetic acid, and proton shuttles

I think the information has been taken from Russian to English by a machine translator, as well, I’m not a chemist, so please bear with my interpretation. It seems that Russian researchers have determined why gold, inert at the macroscale, is a good catalyst at the nanoscale. From a July 28, 2015 news item on Azonano,

Being found mostly in the native state, gold is one of the oldest elements known to man. The affection to gold was determined by it’s unusual properties – heft, shine and ability to withstand oxidation and corrosion.

The combination of properties determined gold use in the jewelry and as a coinage metal. The ancient alchemists working with gold were struggled by utmost chemical resistance of this element – it did not react with concentrated acids or alkali solutions even at high temperatures. Actually, it is the chemical inertness that makes gold to appear in a native form and not as a part of a mineral.

Later analysis established that gold compounds can not only compete with traditional nickel and palladium-based catalysts in the common reactions, but to surpass them. Besides that, gold compounds often demonstrated principally novel types of reactivity compared to well-established catalysts. This allowed chemists to discover a bunch of new chemical reactions and predetermined a fascinating boom in gold catalysis that we have observed in the recent years.

A July 24, 2015 Institute of Organic Chemistry, Russian Academy of Sciences press release on EurekAlert, which also originated the news item, reveals more about the study,

Professor Ananikov and co-workers introduced gold into well-known catalytic system which led to dramatic change of the reactivity and furnished the formation of novel gold-containing complexes. The complexes appeared to be air stable and were isolated in the individual state. A single crystal X-Ray diffraction study ascertained the existence of unique structural motif in the molecule, which can not be explained within conventional mechanistic framework.

The study was carried out using both theoretical and experimental approaches. Dedicated labeling of the reagents allowed observation of molecular re-organizations. Variation of reaction conditions helped to estimate key factors governing the discovered transformation. In addition, computational study of the reaction provided the models of certain intermediate steps, which were invisible for experimental investigation. The theoretical data obtained was in excellent agreement with experiment, proposing the reaction mechanism, where a molecule of acetic acid serves as a proton shuttle, transferring the hydrogen atom between the reaction centers.

The belief of gold inactivity towards chemical transformations resulted in the fact, that organometallic chemistry of gold was developed significantly later compared to other coinage metals (like silver, nickel or copper). Today, our goal is to “introduce gold catalysis as a valuable practical tool in fine organic chemistry, competitive with other transition metal catalysts”, says Prof. Ananikov.

Here’s a link to and a citation for the paper,

Carboxylic Group-Assisted Proton Transfer in Gold-Mediated Thiolation of Alkynes by Sergey S. Zalesskiy, Victor N. Khrustalev, Alexandr Yu. Kostukovich, and Valentine P. Ananikov. Organometallics, Article ASAP DOI: 10.1021/acs.organomet.5b00210 Publication Date (Web): July 22, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.