Chemistry of Essential Oils
K. Hüsnü Can Başer, Gerhard Buchbauer in Handbook of Essential Oils, 2020
The other major route to citral is shown in Figure 6.39. This starts from isobutene (217) and formaldehyde (218). The ene reaction between these produces isoprenol (219). Isomerization of isoprenol over a palladium catalyst gives prenol (220) and aerial oxidation over a silver catalyst gives prenal (senecioaldehyde) (221). When heated together, these two add together to form the enol ether (222), which then undergoes a Claisen rearrangement to give the aldehyde (223). This latter molecule is perfectly set up (after rotation around the central bond) for a Cope rearrangement to give citral (71). Development chemists have always striven to produce economic processes with the highest overall yield possible thus minimizing the volume of waste and hence environmental impact. This synthesis is a very good example of the fruits of such work. The reaction scheme uses no reagents, other than oxygen, employs efficient catalysts, and produces only one by-product, water, which is environmentally benign.
Indoor Air Pollution
William J. Rea, Kalpana D. Patel in Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
Sugie et al.41 reported three cases of sudden death due to the inhalation of portable cooking stove fuel (case 1), cigarette lighter fuel (case 2), and liquefied petroleum gas (LPG) (case 3). Specimens of blood, urine, stomach contents, brain, heart, lung, liver, kidney, and fat were collected and analyzed for propylene, propane, isobutene, and n-butane by headspace gas chromatography (GCV). n-Butane was the major substance among the volatiles found in the tissues of cases 1 and 2, and propane was the major substance in case 3. A combination of the autopsy findings and the gas analysis results revealed that the cause of death was ventricular fibrillation induced by hard muscle exercise after gas inhalation in cases 1 and 2, and that the cause of death in case 3 might be hypoxia. It is possible that the victim in case 3 was under anesthetic toxicity of accumulated isobutene which is a minor component of liquefied petroleum gas.
Synthetic Polymers in Cosmetics
E. Desmond Goddard, James V. Gruber in Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
2. Nonionic Conditioning Polymers Poly(vinylpyrrolidone). PVP was mentioned previously for its thickening (Section II.A.1.e) and hair fixative (Section III.A) attributes. The cyclic amide functionality of the PVP pyrrolidone ring bears a strong resemblance to the amide polypeptide bonds that hold the proteins of hair and skin together. This similarity suggests that PVP will adsorb to the proteins of the hair and skin. It is generally felt that application of PVP films to the skin, especially, and also hair imparts a soft and silky feeling (42,171). The use of PVP in skin care formulations can allow reduced amounts of the oily conditioners required and leaves a less greasy feel.Hydrogenated Poly(isobutene)s. The proteins that comprise hair and skin are chemically unique polymers. When they are present in a dried state, they are very hydrophobic; when fully wetted, they hydrate and are quite hydrophilic. This dual functionality is characteristic of oleaginous materials. Oleaginous polymers tend to spread quickly over the surface of hair and skin, driven primarily by their low surface tension on these protein substrates. Examples of widely used oleaginous conditioners are the silicone polymers discussed in Chapter 7.
Noninvasive detection of COPD and Lung Cancer through breath analysis using MOS Sensor array based e-nose
Published in Expert Review of Molecular Diagnostics, 2021
Binson V A, M. Subramoniam, Luke Mathew
To differentiate patients from controls, ‘breath print’ produced by the TGS sensors was analyzed. In sensor response analysis, the maximum output value is the foremost feature and is crucial in the discrimination. Figure 2 depicts the sensor array maximum values to the exhaled breath of a patient with lung cancer, a patient with COPD, and a healthy control showing error bars with standard error. These bar graphs illustrate that the sensor array produces higher voltages to the samples of patients with pulmonary diseases and a lesser voltage to healthy control samples. The higher concentrations of volatile organic compounds such as carbon monoxide, isobutene, ethanol, propane, acetone, ammonia, etc in the expired breath of patients with respiratory diseases increased the output voltage [26–28]. The TGS sensors used in our work are cross-reactive sensors. In these types of sensors, an output voltage is generated to a combination of VOCs instead of producing an output response to a particular VOC.
Particle and organic vapor emissions from children’s 3-D pen and 3-D printer toys
Published in Inhalation Toxicology, 2019
Jinghai Yi, Matthew G. Duling, Lauren N. Bowers, Alycia K. Knepp, Ryan F. LeBouf, Timothy R. Nurkiewicz, Anand Ranpara, Todd Luxton, Stephen B. Martin, Dru A. Burns, Derek M. Peloquin, Eric J. Baumann, M. Abbas Virji, Aleksandr B. Stefaniak
Total VOC (TVOC) concentration in the chamber was measured using a real-time photo-ionization detector with 10.6 eV ultraviolet discharge lamp (Model 3000 ppbRAE, RAE Systems, San Jose, CA). This instrument was factory calibrated using isobutylene and span checked with isobutylene prior to use and is capable of measuring down to 1 ppb (2.3 µg/m3 isobutylene equivalent). Measurement results in ppb were converted to µg/m3 isobutylene equivalents using the molecular weight of isobutylene. Samples of VOCs were collected using whole-air 6 L Silonite®-coated canisters (Entech Instruments, Inc., Simi Valley, CA) followed by off-line analysis by gas chromatography-mass spectrometry (GC-MS, Model 7890-5975, Agilent Technologies Inc., Santa Clara, CA) to quantify 17 VOCs (NIOSH 2018) plus acetaldehyde and styrene. Two canister samples were collected during replicate printing tests, one during the background phase and the other at the mid-point of the printing phase. Collection took a period of about 1–2 min per sample.
The need for new control strategies for particulate matter in parenterals
Published in Pharmaceutical Development and Technology, 2019
Johannes Poms, Stephan Sacher, Matthias Nixdorf, Michael Dekner, Sabine Wallner-Mang, Ines Janssen, Johannes G. Khinast, Robert Schennach
Particulate matter was prepared by milling and sieving. Clean-Pak amber glass vials (Sigma Aldrich, Darmstadt, Germany) were crushed and ground in a mechanical ball mill PM 100 (Retsch, Hann, Germany). Polyethylene, polytetrafluoroethene and bromo-isobutene-isoprene rubber stoppers (all samples of production line) were ground in a CryoMill (Retsch, Hann, Germany) at an agitation frequency of 20 s−1 at liquid nitrogen temperature of −196 °C. In order to prevent particle agglomeration, small amounts of chalk were added. Stainless martensitic steel (X20Cr20) swarf was produced with a file. All impurities were separated with a sieving machine (Retsch AS200, Hann, Germany) with analytical meshes of 50, 80, 100, 160, 250, 400, 630, 800 µm generating seven different size classes in-between.
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