107 quotes found
"I was fortunate enough to hit on the focussing principle used in the mass spectrograph"
"It has long been known that the chemical atomic weight of hydrogen was greater than one-quarter of that of helium, but so long as fractional weights were general there was no particular need to explain this fact, nor could any definite conclusions be drawn from it."
"Since it is a close analogue of the ordinary spectrograph and gives a spectrum depending upon mass alone, the instrument is called a mass spectrograph and the spectrum it produces a mass spectrum."
"Should the research worker of the future discover some means of releasing this [atomic] energy in a form which could be employed, the human race will have at its command powers beyond the dreams of scientific fiction"
"We learned to make elephants fly."
"In small-molecule mass spectrometry, molecules are first ionized by collision with a high-energy electron beam. The ions then fragment into smaller pieces, which are magnetically sorted according to their mass-to-charge ratio (m/z). The ionized sample molecule is called the molecular ion, M1, and measurement of its mass gives the molecular weight of the sample. Structural clues about unknown samples can be obtained by interpreting the fragmentation pattern of the molecular ion. Mass-spectral fragmentations are usually complex, however, and interpretation is often difficult. In biological mass spectrometry, molecules are protonated using either electrospray ionization (ESI) or matrix-assisted laser desorption ionization (MALDI), and the protonated molecules are separated by time-of-flight (TOF)."
"I feel sure that there are many problems in Chemistry which could be solved with far greater ease by this than by any other method. The method is surprisingly sensitive — more so even than that of Spectrum Analysis, requires an infinitesimal amount of material, and does not require this to be specially purified: the technique is not difficult if appliances for high vacua are available."
"Nuclear magnetic resonance spectroscopy depends on the absorption of energy when the nucleus of an atom is excited from its lowest energy spin state to the next higher one. The nuclei of several elements can be studied by NMR. The two elements that are the most common in organic molecules (carbon and hydrogen) have isotopes (1H and 13C) capable of giving NMR spectra that are rich in structural information. A proton nuclear magnetic resonance (1H NMR) spectrum tells us about the environments of the various hydrogens in a molecule; a carbon-13 nuclear magnetic resonance (13C NMR) spectrum does the same for the carbon atoms. Separately and together 1H and 13C NMR take us a long way toward determining a substance’s molecular structure. We’ll develop most of the general principles of NMR by discussing 1H NMR, then extend them to 13C NMR. The 13C NMR discussion is shorter, not because it is less important than 1H NMR, but because many of the same principles apply to both techniques."
"In subsequent chapters, discussions regarding a number of nuclear magnetic resonance (NMR) techniques that could not be implemented when nuclear magnetic resonance was first discovered are presented. Their advent required, for example, strong magnetic fields and/or cryoprobes to accommodate limited sample availability. Pulsed field gradients (PFGs) have improved solvent suppression, have enabled efficient selective excitation, and have made accessible a different time range to diffusion coefficient measurement. Such developments have, of course, been made in parallel with increasing access to powerful computers and sophisticated software, permitting speedy processing and analysis of the various types and sizes of acquired data sets. Instrumental and software developments in the past 30 to 40 years have meant that NMR spectroscopy is now used in a wide range of scenarios. Synthetic chemists use NMR to elucidate structures of small molecules. It is employed in pharmaceutical industries for structure elucidation and drug development and screening (Chapter 3, Section 7.1). Biochemistry and biotechnology sectors utilise NMR to probe solution structures and functions of biological polymers (Chapter 7), and it is increasingly used in biomedicine (in particular, biomarker discovery; Chapter 6) for the analysis of complex matrices. Materials science (both soft and hard matters) is another application area in which solution and solid-state NMR has proved extremely valuable. While not an exhaustive list of applications, this is an illustration of the breadth of science that has benefitted from this analytical technique."
"The electron paramagnetic resonance discovered by Evgenii Konstantinovich is undoubtedly a first-class thing. It is a pity that nuclear magnetic resonance 'floated away'. Clearly, if Evgenii Konstantinovich had worked in better conditions, he would have done much more."
"In the absence of an external magnetic field, the spins of magnetic nuclei are oriented randomly. When a sample containing these nuclei is placed between the poles of a strong magnet, however, the nuclei adopt specific orientations, much as a compass needle orients in the earth’s magnetic field. A spinning 1H or 13C nucleus can orient so that its own tiny magnetic field is aligned either with (parallel to) or against (antiparallel to) the external field. The two orientations don’t have the same energy, however, and aren’t equally likely. The parallel orientation is slightly lower in energy by an amount that depends on the strength of the external field, making this spin state very slightly favored over the antiparallel orientation. ... If the oriented nuclei are irradiated with electromagnetic radiation of the proper frequency, energy absorption occurs and the lower-energy state “spinflips” to the higher-energy state. When this spin-flip occurs, the magnetic nuclei are said to be in resonance with the applied radiation—hence the name nuclear magnetic resonance."
"For magnetic fields that can be routinely produced in the laboratory, the transitions between energy levels for nuclear magnetic dipoles occur in the radio-frequency range, and the transitions between energy levels for unpaired electron spins occur in the microwave range. Nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) yield such valuable structural information that they have become indispensable in chemistry."
"The nuclei of certain elements, including 1H nuclei (protons) and 13C(carbon-13) nuclei, behave as though they were magnets spinning about an axis. When a compound containing protons or carbon-13 nuclei is placed in a very strong magnetic field and simultaneously irradiated with electromagnetic energy of the appropriate frequency, nuclei of the compound absorb energy through a process called magnetic resonance. The absorption of energy is quantized. ... We can use NMR spectra to provide valuable information about the structure of any molecule we might be studying. In the following sections we shall explain how four features of a molecule’s proton NMR spectrum can help us arrive at its structure."
"Back at Caltech, my research was going strong, and we had four different laboratories busy with experiments and people. In one of these laboratories, we were continuing with our work on coherence; in others, advancing techniques for shorter time resolution and for developing an optical analog for nuclear magnetic resonance (NMR). In NMR, the spin of nuclei with their transitions at radio frequencies is used for a variety of applications, ranging from the studies of molecular structure to magnetic resonance imaging (MRI), which is now commonly used in hospitals throughout the world."
"I dislike the whole business of experiments on animals, unless there's some very good and altogether exceptional reason in a particular case. The thing that gets me is that it's not possible for the animals to understand why they're being called upon to suffer. They don't suffer for their own good or benefit at all, and I often wonder how far it's for anyone's. They're given no choice, and there's no central authority responsible for deciding whether what's done in this case or that is morally justifiable. These experimental animals are just sentient objects; they're useful because they're able to react; sometimes precisely because they're able to feel fear and pain. And they're used as if they were electric light bulbs or boots. What it comes to is that whereas there used to be human and animal slaves, now there are just animal slaves. They have no legal rights, and no choice in the matter."
"Animals themselves cannot plead their cause, and those who plead it for them have no obvious financial or other selfish interest in the issue, although many may have “vested” their emotions in it. When we turn to special gain from maintaining existing practices, special loss if they were to be changed, we find a large number of groups whose views might be discounted. Butchers, furriers, hunters, cattlemen, chicken farmers, scientific experimenters on animals would, unless compensated, all have to suffer significant personal loss if we were to change our practices. They cannot therefore be expected to see the moral issue without the distortion of special interest. The scientists might claim that in their case their own interest coincides with a universal human interest, but I think the butcher and the furrier could make a similar claim[.]"
"Animals can not disapprove, but they can complain and protest, at least until their vocal chords are cut to spare experimenters their protests."
"Last year a Dutch animal breeding centre sent me two chimpanzees as a gift. I killed one and cut its heart out. The other wept bitterly and was inconsolable. The sad chimp has long since happily mated again and lives with lots of other animals on a pleasant game farm near Villiersdorp. I vowed never again to experiment with such sensitive creatures, but the memory of that weeping chimp has remained with me. It was taken for granted, of course, that he was weeping for his mate but I've since had some thoughts on the subject which made me wonder whether perhaps he was weeping for the human race. The idea is not as silly as it sounds. In our doings there is much to weep over and even a chimpanzee would never behave in some of the contradictory ways we think of as normal."
"It’s very easy, for instance, to cure Alzheimer’s in mice. But those things don’t translate to humans."
"I should be writing a third paper on the Nerves, but I cannot proceed without making some experiments, which are so unpleasant to make that I defer them. You may think me silly, but I cannot perfectly convince myself that I am authorised in nature, or religion, to do these cruelties—for what?—for anything else than a little egotism or self-aggrandisement; and yet, what are my experiments in comparison with those which are daily done? and are done daily for nothing."
"In concluding these papers, I hope I may be permitted to offer a few words in favour of anatomy, as better adapted for discovery than experiment. … Experiments have never been the means of discovery; and a survey of what has been attempted of late years in physiology, will prove that the opening of living animals has done more to perpetuate error, than to confirm the just views taken from the study of anatomy and natural motions."
"Nearly all modern techniques of social conditioning were first established with animal experiments. As were also the methods of so-called intelligence testing. Today behaviourists like Skinner imprison the very concept of man within the limits of what they conclude from their artificial tests with animals."
"There will come a time when the world will look back to modern vivisection in the name of science as they now do to burning at the stake in the name of religion."
"To hold vivisection to be never justified is a hard belief. But so is its opposite. I believe it is never justified because I can see nothing (except our being able to get away with it) which lets us pick on animals that would not equally let us pick on idiot humans (who would be more useful) or, for the matter of that, on a few humans of any sort whom we might sacrifice for the good of the many. If we do permit vivisection, here if anywhere we are under the most stringent minimum obligations. The very least we must make sure of is that no experiment is ever duplicated, or careless, or done for mere teaching's sake or as a substitute for thinking. Knowing how often, in every other sphere, pseudo-work proliferates in order to fill time and jobs, and how often activity substitutes for thought, and then reading the official statistics about vivisection, do you truly believe we do make sure?"
"To what extent do we have a right to torture animals? … Experiments are torturing animals, let's say. That's what they are. So to what extent do we have a right to torture animals for our own good? I think that's not a trivial question."
"As the main work of civilisation has been the vindication of the rights of the weak, it is not too much, I think, to insist that the practice of Vivisection in which this tyranny of strength culminates is a retrograde step in the progress of our race—a backwater in the onward flowing stream of justice and mercy, no less portentous than deplorable."
"The love of a dog for his master is notorious; in the agony of death he has been known to caress his master, and every one has heard of the dog suffering under vivisection, who licked the hand of the operator; this man, unless he had a heart of stone, must have felt remorse to the last hour of his life."
"Libby had eaten her last meal the night before: orange, banana, monkey chow. While eating she had observed us with curiosity. Her hands resembled the hands of a newly born child, her face seemed almost human. Perhaps because of her eyes. They were so sad, so defenseless. We had called her Libby because Dr. Maurice Albin, the anesthetist, had told us she had no name, we could give her the name we liked best, and because she accepted it immediately. You said ‘Libby!’ and she jumped, then she leaned her head on her shoulder. Dr. Albin had also told us that Libby had been born in India and was almost three years, an age comparable to that of a seven-year-old girl. The rhesuses live 30 years and she was a rhesus. Prof. Robert White uses the rhesus because they are not expensive; they cost between $80 and $100. Chimpanzees, larger and easier to experiment with, cost up to $2,000 each. After the meal, a veterinarian had come, and with as much ceremony as they use for the condemned, he had checked to be sure Libby was in good health. It would be a difficult operation and her body should function as perfectly as a rocket going to the moon. A hundred times before, the experiment had ended in failure, and though Professor White became the first man in the entire history of medicine to succeed, the undertaking still bordered on science fiction. Libby was about to die in order to demonstrate that her brain could live isolated from her body and that, so isolated, it could still think."
"How fortunate we didn't have these animal tests in the 1940s, for would probably not have been granted a licence, and possibly the whole field of antibiotics might never have been realised."
"Humans are currently the dominant species on earth and exercise a great deal of power and control over nature. But very few believe might makes right, so the fact that we have greater power cannot enter into a justification of our use and treatment of animals. Rather, where other beings are under our power, we should feel obligated to show self-restraint and to act out of mercy and compassion. We cannot avoid causing harm to other beings in the process of living our own lives. Nor does morality consist in trying to be perfect and pure. But we can adopt an orientation toward minimizing the amount of harm we cause and taking full responsibility for it, seeing it for what it is. To justify animal experimentation is to start at one end of a continuum. Much of what we do will be morally acceptable (in our eyes), and we will chip away at the extremity where what we do shades into cruelty. I no longer believe that a general moral justification of animal experimentation can be given."
"The victory of vivisection marks a great advance in the triumph of ruthless, non-moral utilitarianism over the old world of ethical law; a triumph in which we, as well as animals, are already the victims, and of which Dachau and Hiroshima mark the more recent achievements."
"The professional and financial interest in continuing animal experimentation helps to explain at least some resistance to the notion that animals have a complex emotional life and are capable of experiencing the higher emotions, such as love, compassion, altruism, disappointment and nostalgia. To acknowledge such a possibility implies certain moral obligations. If chimpanzees can experience loneliness and mental anguish, it becomes more wrong to use them for experiments in which they are isolated and anticipate daily pain."
"It is often said that if slaughterhouses were made of glass, most people would be vegetarians. If the general public knew what went on inside animal experimentation laboratories, they would be abolished. However, the parallel is not exact. Slaughterhouses are invisible because the public wants them that way. Everyone knows what goes on inside them; they simply do not want to be confronted with it. Most people do not know what goes on with animal experimentation. Slaughterhouses allow visits. Laboratories where animal experiments are performed are secretive. Perhaps those who conduct the experiments know they would be stopped if what they do were known even by other scientists. Perhaps they are ashamed."
"Rats and mice are not generally regarded as pets, but as pests; they have few defenders. Yet the pain a rat or a mouse feels is every bit as real as that of any pet. In laboratories, they suffer, as anybody who has heard them moan, cry, whimper and even scream knows. The experimenters dissimulate about this by insisting that they are merely vocalising."
"One type of medical research involves ascertaining whether certain pathological conditions in humans can be alleviated or cured by certain drugs. Animals are used as "models" upon which to test these treatments. To do this it is necessary for the animal subject to have the condition in question, and in order to bring this about healthy animals are made sick. … It turns out, however, that the conditions artificially induced have little in common with the naturally occurring diseases in animals (when these exist) and much less in common with the diseases in man."
"Arguments to the effect that it is wrong to cause pain and suffering to animals are often rejected by claiming that animals simply do not suffer. … Ironically, it is precisely upon the assumption that animals do suffer from stress, fear, and pain in a manner similar to humans that the validity of much of animal experimentation rests. Few, if any, conditions are studied as widely in animals as are pain, stress, ulcers, fear, and anxiety."
"At present ... the difference between an animal-experimenter's laboratory and a torture chamber is often imperceptible from his victims' point of view."
"Make sure the check you write to a charity doesn't pay for cruel experiments on animals. Your donation should help end suffering — not cause it."
"Misleading may be the claims that procedures [of animal testing] are carried out under anaesthesia. Restraining devices and paralysing drugs can today be so effective that an anaesthetic is often unnecessary from the purely practical point of view. The risk of giving a dose too large and thereby losing an expensive chimpanzee, for example, may often tempt a scientist or technician, inexperienced with sophisticated anaesthetic techniques, to give a dose too small, from which the animal quickly recovers — but not of course until after it has been strapped securely to the operating table."
"Differences in reaction to toxic substances vary considerably between species so that the value of these tests remains doubtful. Although thalidomide was extensively tested on animals in several countries, its terrible properties were not discovered. Conversely, penicillin, the greatest medical discovery of the century, was not extensively tested on animals before its miraculous therapeutic qualities were demonstrated in human patients. If it had been fully tested on animals its high toxicity for guinea pigs would have almost certainly prevented its clinical use."
"Sometimes captured from the great arboreal freedom of their jungle homes, monkeys are closely confined in cages only three or four feet square. … They can never sit or lie down on a flat, soft or yielding surface. Little wonder that by the time they are needed for the knife or the needle they are so crazed or inert that they are no longer representative examples of animal life. Psychologists who study the behaviour of thousands of such creatures annually, rarely make allowances for the fact that their pathetic subjects have been so deprived that they have become more like monsters than animals. Many people who have experienced close affectionate relationships with individuals of other species testify to the considerable potential for emotional and intellectual development that animals have. When properly cared for a pet dog or cat can develop great subtleties of behaviour that the laboratory animal never shows. Those who have been fortunate enough to closely observe unfrightened animals living in the wild are often struck by the complexity and richness of the life they lead. These positive pleasures the laboratory animal never knows; for him the same four white walls and the smell of disinfectant."
"It is idle to spend a single moment in advocating the rights of the lower animals, if such rights do not include a total and unqualified exemption from the awful tortures of vivisection-from the doom of being slowly and mercilessly dismembered, or flayed, or baked alive, or infected with some deadly virus, or subjected to any of the numerous modes of torture inflicted by the Scientific Inquisition."
"Those who experiment with operations or the use of drugs upon animals, or inoculate them with diseases, so as to be able to bring help to mankind with the results gained, must never quiet any misgivings they feel with the general reflection that their cruel proceedings aim at a valuable result. They must first have considered in each individual case whether there is a real necessity to force upon any animal this sacrifice for the sake of mankind. And they must take the most anxious care to mitigate as much as possible the pain inflicted. How much wrong is committed in scientific institutions through neglect of anaesthetics, which to save time or trouble are not administered! How much, too, through animals being subjected to torture merely to demonstrate to students generally known phenomena! By the very fact that animals have been subjected to experiments, and have by their pain won such valuable results for suffering humanity, a new and special relation of solidarity has been established between them and us. From that springs for each one of us a compulsion to do to every animal all the good we possibly can. By helping an insect when it is in difficulties, I am only attempting to cancel part of man's ever new debt to the animal world."
"I believe I am not interested to know whether Vivisection produces results that are profitable to the human race or doesn't. To know that the results are profitable to the race would not remove my hostility to it. The pains which it inflicts upon unconsenting animals is the basis of my enmity towards it, and it is to me sufficient justification of the enmity without looking further. It is so distinctly a matter of feeling with me, and is so strong and so deeply-rooted in my make and constitution, that I am sure I could not even see a vivisector vivisected with anything more than a sort of qualified satisfaction."
"Some barbarians seize this dog, who so prodigiously excels man in friendship, they nail him to a table, and dissect him living, to show the mezarian veins. You discover in him all the same organs of sentiment which are in yourself. Answer me, machinist, has nature arranged all the springs of sentiment in this animal that he should not feel? Has he nerves to be incapable of suffering? Do not suppose this impertinent contradiction in nature."
"has not been generally used as a feedstock in simple thermal cracking... because the decomposition temperature is too high and yield of useful products too low. Nevertheless... pyrolysis of methane has been used for the production of acetylene and ... Diamonds can be formed... under suitable conditions... [E]arly stages of...decomposition are... well understood... but... details of later stages are not... clear... All oxidation reactions, including oxidative pyrolysis, have been excluded."
"[A]n overall model for the simulation of pyrolysis reactors should... include the heat, momentum, s differential equations, physicochemical properties (specific heats, enthalpies, thermal conductivities, etc.) firing-box patterns, and sometimes fluid dynamic characterization (as in advanced cracking reactors)."
"Flash pyrolysis has the potential of producing maximum yields of gases and liquids from coal and organic solid wastes such as municipal refuse, tree bark, cow manure, rice hulls and grass straw using simple process equipment. The main features of the process are near ambient pressure, no requirement for added chemicals, low capital investment, high feed throughput flexibility of feedstock, variability of temperature, and minimum feed pretreatment."
"The pyrolysis of and is often the process of choice for the production of . ...Marketing of the products of from ethane pyrolysis is greatly simplified by the low yield of by-products. ...Pyrolysis of ethane and propane produces the lowest yield of byproducts, which... minimizes the size of downstream units... as the depropanizer, debutanizer, and compressors."
"Fire, as the agent for , was a favorite tool of the alchemist. Although the general prevalence... of pyrolysis has long been recognized... in the last six decades... the subject has assumed a scientific basis. Since many... data on have been incidental observations... the information is widely scattered... [T]hat ...records of many melting-point determinations are accompanied by ..."It melts with decomposition" is ...evidence ...the subject ...has ...an unorganized past."
"The transformation of a compound into another substance, or... substances, through... heat alone is... pyrolysis."
"Frequently, pyrolyses are s, but... "Pyrolysis" is... broader... [and] more concise. In "decompositions", there is... formation of at least two simpler substances. In pyrolyses... not always... [R]earrangements may be caused by heat alone. ...[F]ormation of large molecules ...is often effected by heat. Both ...are pyrolytic ...but it would be awkward to classify them as decompositions."
"Some compounds decompose at the temperature of boiling water... others require red heat. ...[C]ompounds may be stable at -40° but not at 0°. All... if caused by temperature alone, are... pyrolysis."
"[T]he great majority of pyrolyses occur at "high" temperatures, but this only means... familiarity with compounds which cannot exist at ordinary temperatures is... extremely limited."
"Occasionally... it will be helpful to note the effect of catalysts... Frequently in s, it is difficult to distinguish between the catalytic and the non-catalytic. ...Glass, or surfaces are the ones which are most used in laboratory pyrolyses. Their catalytic action is, at the best, very slight."
"In larger scale work... metallic surfaces [are usually necessary]. Wilson and Bahlke... reported that in cracking stills... -steels ("stainless" steels) [are best], or aluminum or calorized iron. Copper and some s are not satisfactory, neither... [is] ... These authors were interested in ..."
"Franz Fischer... performed... pyrogenic experiments in a tinned-iron tube, which would have failed in an iron tube because of deposition or other causes. ...[He] has shown that a ferrous sulfide inner lining [formed by passing through] in an iron tube also prevents carbon deposit[s] ..."
"The subject of wood distillation has... been treated in... this series. ...[W]ood is not a compound."
"[S]ubstances... identified among... products of wood distillation may be arranged... in a few groups of related compounds. Much of the accurate knowledge... is due to the work of Klason."
"The groups from [wood distillation] are 1. s; formic to caproic, especially . Also, furoic, angelic, s, and valerolactone. For different woods, the total acid, calculated as acetic acid, varies between 4.3 and 6.8[%]... In vacuum distillation... formic acid may be... as high as 35[%] of the acetic acid, but in ordinary distillation at atmospheric pressure, it varies from 10-20[%] of the acetic acid. Only these two acids appear to be formed in appreciable amounts. 2. Alcohols; especially and , but also isoamyl and isobutyl alcohols, and buten-3-ol-2. The content is usually... 1.3-2[%]. 3. Esters; formed by interaction of the above acids and alcohols. 4. Ketones; ... and... its homologs... [plus] small quantities of , methyl cyclopentanone, and . The acetone is not a primary [distillation] product... but is formed secondarily from the acetic acid... homologs of acetone have a similar history. 5. Aldehydes; , , methylal and dimethyl acetal, valeric aldehyde, and methyl furfural. The pentosans are... the source of the furfural and other... homologs of furan... 6. Phenols and phenol methyl ethers [only about 1 percent of the wood distilled], mostly s of di- and tris. ...These substances come largely from the . 7. [< 0.2 percent of the total] , methyl amine, and methyl pyridine... 8. , , melene, etc. 9. es; the yields of , and vary with the maximum temperature of distillation, but at 350-400° the yields from s are about 8, 4 and 1.5[%], respectively. 10. Water; the yield... varies... 22.3-27.8[%]. 11. '. ...30-45[%] ...depending on the wood, and on the maximum temperature."
"The of mineral or organic material was one of the few preparative methods available to the alchemists and the first chemists. That materials could undergo profound changes at high temperatures became a well-recognized principle... emphasized by... landmarks as the formation of by heating ferrous sulfate (copperas) described by ... Brandt's discovery of in 1669 by destructive distillation of residues from ... isolation of benzene from oil gas by Faraday in 1825 and of pyrrole from bone oil by Runge in 1834."
"s, alkalis, and many other inorganic reagents were available... in the early nineteenth century... [T]heir use often added to... descriptive organic chemistry... without clarifying structural relationships. ...[V]igorous pyrolysis of organic compounds, involving no addition of further groups, remained a common technique until about the end of the nineteenth century. ...[M]any high-temperature reactions are fragmentations which produce simple products ...[D]irect of ...carboxylic acids and ...similar decomposition of carboxylic salts by heating with lime or are... examples."
"Mitscherlich prepared benzene as early as 1834 by vigorous distillation of and lime."
"Prompted by the need of non-petroleum-based fuels, coal research has reemerged... Pyrolysis research... has gained... momentum because of its close connection to combustion, hydropyrolysis and liquification. Spectroscopic and other instrumental techniques are... producing... information about coal structure and pyrolysis mechanisms, while modeling efforts are breaking new ground in sorting out chemical and physical phenomena... [P]ostulates and assumptions of current work provide a meaningful starting point in... theoretical descriptions of greater validity and applicability."
"[T]he survey of experimental results will be confined to flash pyrolysis at the exclusion of slow pyrolysis or ."
"Flash pyrolysis poses three experimental difficulties..: (i) control and measurement of the temperature-time history of the coal particles (ii) suppression of secondary reactions (iii) quantitative collection of products."
"[M]easurement of the coal particles' temperature is not trivial. In many cases the temperature... must be calculated from a model. The other two experimental problems, the suppression of secondary reactions and the collection of products, depend on the reactor geometry and flow pattern..."
"[P]roduct distribution is the most essential information relative to the commercial utilization of pyrolysis and... sheds considerable light on reaction mechanisms."
"[P]roducts can be classified into two groups relative to the temperature dependence of the yields. , water and evolve at lower temperatures with ultimate yields that are essentially independent of temperature above 700°C. The second group... of gaseous hydrocarbons, and evolve at higher temperatures. The ultimate yield of these... continues increasing... up to 1,000°C or higher."
"In s, makes up 50-80% of the weight loss, the remaining consisting of gases, water and ."
"We are... concerned with the evolution of tar and gases during the plastic state of coal. In this... consists of two processes in series: diffusion through the molten coal to some internal surface, that of a bubble or a pore; and transport with the bubble or through the pore to the surface of the particle. The role of preexisting pores is not well understood. ...[A] certain fraction of preexisting pores (< 60 Å) collapse during pyrolysis perhaps due to effects. Pores... 60-300 Å were preserved... but one could not distinguish preexisting pores and pores generated by the evolution of bubbles. It appears likely... the major... mass transfer occurs via bubbles while preexisting bubbles play a... minor role."
"Fast pyrolysis is a new technology that shows... potential for producing... liquid... for fuel applications or as a source for... chemicals."
"Wood and biomass can be used in a variety of ways to provide energy: • by direct combustion... for... heating.., steam production and hence electricity generation. • by gasification to provide fuel gas... for heat, or in an engine or turbine for electricity generation. • by fast pyrolysis to provide a liquid fuel... for fuel oil in... static heating or electricity generation... [and] to produce... chemicals."
"Fast pyrolysis is a high temperature process in which biomass is rapidly heated in the absence of oxygen. ...[I]t decomposes to generate mostly vapours... s and some . After cooling and condensation, a... liquid is formed which has a heating value about half... conventional . ...Fast pyrolysis ...is carefully controlled to give high yields ..."
"[E]ssential features... • high heating and heat transfer rates... usually requires finely ground biomass feed • carefully controlled... reaction temperature... [~]500C... vapour phase... short vapour residence typically [<]2 sec... • rapid cooling of pyrolysis vapours to give... bio-oil product."
"[M]ain product, bio-oil... in yields up to 80%... with byproduct char and ... used within... process so no waste..."
"Pitch is a highly viscous residue remaining from wood pyrolysis... In the days of s, pitch was extremely valuable to seal the wood planking and for... where a tightly sticking, water-resistant material was needed."
"Eventually it was understood that the residue from a fire came from... insufficient oxygen (air) to consume the wood completely. From that... came... recognition of making charcoal deliberately by heating wood in the absence of air, or burning under severely air-limited conditions. ...[I]t was [later] realized ...volatile materials "cooked" out ...during conversion... also had valuable uses."
"Production of ... with [other] chemical products... involves pyrolysis, i.e. decomposition of compounds through application of heat."
"Because pyrolysis converts wood to highly ... charcoal... [it] is also known as . Since volatile compounds are driven off, but... residual non-volatile[s are] altered.., another name... is ."
"[T]hermal decomposition of wood begins [≈]250°C. Industrial carbonization... at ≈500°C."
"Carbonization drives off moisture... with... low molecular weight organic compounds... from extractives and... pyrolysis of ... s. Condensing vapors from carbonization produces... ... a dilute solution of up to 50 small, polar (...[i.e.] water soluble) organic compounds. ...[M]ost important ...are , , and ."
"Condensable non-aqueous ...wood tars ...[are] produced by pyrolysis and destructive distillation. Tars can be fractionated into [1] light oils, boiling below 200°C... [2] heavy tars, boiling above that... and [3] pitch. Light tars tend to be mixtures of aldehydes, carboxylic acids, esters, and ketones. Heavy oil contains... phenol derivatives; one of its uses... a wood preservative... wood tar creosote..."
"In fuel chemistry... we deal with several kinds of bond, and mixtures of... different compounds. At temperatures high enough to drive pyrolysis of... one kind of bond... other kinds... break... [I]mmediate products may undergo... subsequent reactions. As a result, pyrolysis... give[s] complex mixtures of products... of little utility if the intent is to produce a single product..."
"With... ... sealed within layers of inorganic ... long... geological processes can operate. Assuming typical s... [b]urial to 10 km would be equivalent to... 100-300°C. These... seem too low to drive... pyrolysis reactions... significant at... [≈]350°C. But... time is on our side... in geological time, tens of millions of years for catagenesis of humic kerogen."
"Like their aliphatic counterparts, the smaller phenols are also water-soluble. Phenol... has... solubility...[≈]82 g/kg water. ...Phenols are produced in coal and wood pyrolysis. Any water used in such processes becomes contaminated with phenols (as well as other compounds) and requires processing before being released... into the environment."
"The organic material in oil shales requires pyrolysis to force the catagenesis of ... This can be done above ground in kilns, or underground with the shale still in place."
"Gasification of coal... [goes] back to the 1790s at least. Before World War II, the United States... had... [≈20,000] small coal gassifiers... a popular fuel gas until... the interstate natural gas pipeline network... after World War II. Many... were simple pyrolysis or steam-carbon reactions in... crude equipment having serious environmental problems."
"Groundwater could become contaminated by organic compounds during coal pyrolysis, and by various inorganic compounds liberated as the coal is consumed. Some... pose problems for environmental quality or human health."
"To a large extent, biomass resembles gasification, with some distinctions... The kinds... considered... include wood, wood wastes (e.g. sawdust), and s. Some... grass, such as switchgrass... grown as energy crops might also serve... [R]elative to coal, biomass usually has lower calorific value... and sulfur... higher moisture, higher... and oxygen, and produces a higher yield of volatiles on pyrolysis. ...Generally biomass chars are more reactive than coal chars, so... may[be]... less and oxygen are needed for... [its] gasification."
"[L]iquids can be produced from coal by... pyrolysis... by dissolution... [i.e.] solvent extraction... or by reaction of coal with or with solvents... donating hydrogen (hydroliquification). All... constitute... coal-to-liquids (CTL) technology."
"Pyrolysis of biomass, heavy petroleum fractions, , , and usually produces some amount of liquid product. Pyrolysis... without an externally added... [source] is constrained... Pyrolysis produces liquids, but leaves a residue of carbonaceous char or coke. Usually... gases also form. The... proportions of solid, liquid, and gas depend on the... feedstock and... reaction conditions."
"[L]arge particles may not be heated uniformly... consequently pyrolysis yields are less. Heating rate is also important. During slow heat-up as... in simple... s most coals begin to decompose [≈]350-400°C. ...[L]iquid and gaseous products ...peak ...[≈]425-475°C. This phase of pyrolysis ends ...[≈]500-550°C. ...[V]ery rapid heating [e.g.] in entrained flow gasifiers ...quickly by-passes this stage, so... evolution of liquids is nil."
"pyrolysis is... complicated... by the fact... primary pyrolysis products... are... able to react among themselves... with ... from the moisture in the coal... with char or coke, or... several of these. The products... often called secondary... may differ... from the primary... Primary products can be studied... if... quench[ed]... rapidly or... [fed] directly into a suitable... instrument... [e.g.] a gas chromatograph."
"In industrial practice... design of the pyrolysis reactor affects... composition of liquid products, because... [it] determines how long... primary products are exposed to pyrolysis temperatures..."
"Commercial... applications of pyrolysis have been to produce... a eous fuel... or a char... Liquids... directly are unsuitable... as fuels... Some... downstream operations would be required... Nevertheless, low-temperature s can be refined... into or ."
"Possibly, future events on the world energy scene will revive interest... Pyrolysis offers... simplicity of process and equipment design relative to gasification and hydroliquification. ...[But] competing technologies usually provide high yields of a single type... gas, liquid or solid... which may offset the added complexity and cost..."
"[R]ules change when an external supply of is... available. Hydropyrolysis, i.e. pyrolizing coal in a hydrogen atmosphere, increases the yields of liquids and gases... [H]ydrogen... stabilizes radicals by hydrogen capping before... termination by recombination reactions that... lead to char... Despite this advantage... hydropyrolysis has never been commercialized."
"[S]tories... about "free oil" from coal pyrolysis, often in reference to a low-temperature ... by ... [≈]80 years ago. Many... accompanied by... conspiracy theories... The , and similar carbonization processes... produce a liquid. Presumably, a... clever accountant could figure out how this... could be "free," provided... markets existed for... large amounts of char and gas produced at the same time, and... could be sold... high enough to compensate for giving away the liquid. Then there's the cost of refining the low-temperature into specification-grade marketable fuel..."
"Often... terms carbonization and pyrolysis are used almost interchangeably. Pyrolysis has the broader meaning: breaking... molecules by... heat or thermal energy. ...[P]yrolysis ...could be run to make gases and liquids rather than solids as the primary product. ... narrowly defined, refers to conversion of a starting material into carbon, or a carbon-rich solid. ...[One can] pyrolyze a hydrocarbon feedstock for the purpose of carbonization, but carbonization is not... pyrolysis by another name. Carbonization can be effected without heat as... primary driving force... Carbonization driven by thermal energy usually requires >500°C."
"Pyrolysis of an oil product or natural gas leads to thermal blacks. ...Acetylene black is made by of acetylene. ...[P]reheated to 800°C ...acetylene is introduced and... because the pyrolysis is exothermic, the temperature... reaches ~2500°C. formation takes place... [800°C-~]2000°C. ...2000-2500°C induces partial of the carbon black. Due to... partial graphitic nature, acelylene blacks have... applications where good [electrical and thermal] conductivity... or... very low chemical reactivity is desirable."
"Almost all pyrolysis reactions are endothermic because they involve breaking bonds in stable compounds."
"Pyrolysis of fossil or s... is... accompanied by char formation. In some cases, this is the point... being an example. ...[I]f pyrolysis were ...done to make gaseous or liquid fuels, and no... market existed for the char, it would be possible to... bury the char... [which] would sequester carbon..."
"[P]yrolysis of biomass to produce char for carbon sequestration has multiple benefits... The product... is... called or Agri-char, sometimes (dark earth)... Trials in Australia have produced a doubling... or tripling of crop production... [C]har is likely to retain some... , , and ... Biochars are very porous... taking up and holding moisture. ...By ...stimulating plant growth, biochar has a double impact... First, it... sequesters carbon. Second... increased growth of plants removes CO, from the atmosphere..."
"Annual production of worldwide amounts to some four gigatonnes. A pyrolysis... that yielded only ten percent could produce enough to fertilize some forty million hectares..."
"s are... ancient technology. Biomass pyrolysis would be "low tech." Farmers could build and install their own... Alternatively, a biochar kiln could be mounted on... a truck... and taken from farm to farm..."
"A comprehensive program..: harvesting and shipping biomass to a centralized biomass or plant within the economically limiting radius, and beyond... converting biomass to biochar in small, decentralized units."