The thermodynamics of the reaction of the low-temperature decomposition of hydrogen sulfide into its constituent elements, as well as the unusual state and properties of the resulting diatomic gaseous sulfur, have been and remain the stumbling block of all our research. Since sulfur and hydrogen sulfide have been known since ancient times and an incredible amount of research has been devoted to the study of their properties, the discovery of some fundamentally new states of sulfur caused the categorical rejection by the leadership of the Institute of Catalysis (Parmon and, later, Buchtiyarov) of all the experimental evidence we received, and we ourselves were labeled illiterate charlatans and crooks seeking to surprise the world with an “outstanding discovery” (quote from Parmon).
It should be noted that in the 10 years since our discovery of diatomic gaseous sulfur (February 2006) and up to my expulsion from the Institute of Catalysis (December 2016), we have created and put into operation 4 (four!!!) experimental installations for studying the process of low-temperature decomposition of hydrogen sulfide:
- gas-phase flow;
- gas-phase flow-circulation;
- three-phase flow (gas-liquid-solid catalyst);
- autoclave static.
At the same time, we were able to obtain a conversion of hydrogen sulfide close to 100 %, which has already been published in the scientific literature Read more (PDF)>>. However, for all the time of our research, the directorate of the Institute of Catalysis (Parmon and, later, Bukhtiyarov) did not bother to get acquainted with these installations and with the equipment on which these studies were carried out. Therefore, no additional budget financing of these works could be considered. Our annual attempts to obtain funding from the Russian Foundation for Basic Research (RFBR) were also doomed to failure, for obvious reasons that are well known to ordinary researchers.
It is impossible to understand and explain the attitude of the directorate of the Institute of Catalysis to our research. On the one hand, the lack of the necessary experimental basis (the only instrument for research – the gas chromatograph LHM-8 of 1980) did not allow us to make a material balance for all products (hydrogen sulfide, hydrogen and sulfur gas), which was the basis for recognizing the inconsistency of the results obtained. Moreover, the necessary chemical and instrumental analyses had to be paid for out of our own pockets. On the other hand, the results obtained, for example, in a flow-circulation installation, clearly proved the existence of gaseous sulfur, which should have made the directorate think about obtaining a completely new, previously unknown state of sulfur, which is in itself a scientific discovery that requires the close attention of fundamental science (I quote from Parmon: “… the study of the properties of new substances is not the subject of research by the Institute of Catalysis” (that’s it !!!) ). Therefore, reference is made to the generally accepted “classical ” thermodynamics of the decomposition of hydrogen sulfide, according to which this process violates all the laws of nature, since it requires the use of an unknown energy source. Hence: “It cannot be because it can never be.”
Indeed, “classical” equilibrium thermodynamics considers only isolated systems that exchange neither matter nor energy with the environment. In these systems, chemical processes are carried out by supplying energy from the outside, so the rate and direction of the process depends only on external conditions, and the catalyst does not change the thermodynamics of the process.
At the same time, all processes occurring in Nature are carried out at ambient temperature and pressure without the supply of thermal energy from outside (in this case, we consider only “dark” processes without the participation of sunlight energy). All biological processes are far from equilibrium and have an irreversible character, so for their description, non-equilibrium thermodynamics, or thermodynamics of irreversible processes, was created, which was formed as an independent scientific discipline in the middle of the last century and one of its creators is I. R. Prigozhin. The distinctive features of biological thermodynamics are that the systems considered by it are open to the flows of matter and energy, and the processes carried out are irreversible and far from equilibrium. The inevitability of the emergence of this science was due to the understanding that the vast majority of processes occurring in nature and with the participation of humans are irreversible and cannot be described within the existing “classical” equilibrium thermodynamics, which does not take into account the time factor.
In terms of nonequilibrium thermodynamics of irreversible processes, the role of solid catalysts, on the surface of which chemical reactions are carried out, becomes clear for an open system that are impossible in the gas phase for isolated system. This material was sent on 16.04.2018 for publication in the journal “Kinetics and Catalysis”, but on 05.07.2018 a negative review was received. The corrected version of the manuscript was sent on 16.07.2018 to the “Journal of Physical Chemistry”, where after a six-month review and replacement of 4 (four!!!) reviewers ‘ the manuscript was rejected for publication on 23.02.2019. In addition, the article was rejected in the journal “Advances in Chemistry” (“Uspechi Chimii”) on 11.02.2020, and the manuscript sent to the journal “International Journal of Alternative Energy and Ecology” on 07.10.2019 has not yet received a response from the editorial board. Finally the English version was published in the journal “Molecular Catalysis” MolecCatal-2020-497-111240-Startsev. The paradox of this whole story is that our first publications on the low-temperature decomposition of hydrogen sulfide to produce hydrogen and solid sulfur appeared in 2004 and were co-authored by Parmon. At the same time, Parmon actively professes non-equilibrium thermodynamics, as evidenced by his lectures at Novosibirsk State University and his monographs in Russian and English. Nevertheless, all this time it was Parmon who actively opposed our scientific research, referring to the “classical” equilibrium thermodynamics and the impossibility of carrying out the process at room temperature.
Unfortunately, my fault and misfortune was that I was “brought up” on classical thermodynamics, and I only heard about non-equilibrium thermodynamics “out of the corner of my ear”, since it did not affect my scientific interests for the time being. Being absolutely sure that I was right, I looked for answers to questions from many theorists and specialists in thermodynamics, but everywhere I received an unambiguous answer: there is clearly not enough thermal energy to carry out a low-temperature reaction and there is nowhere to take it. However, the processes of assimilation of hydrogen sulfide, carried out in Nature by sulfur bacteria at ambient temperature and pressure, have always been before our eyes. Therefore, the first textbook for me was the monograph [Haynie D. T. Biological Thermodynamics. Second edition. 2008. Cambridge University Press. The Edinburgh Building, Cambridge CB2 8RU, UK]. Taking this opportunity, I strongly recommend that you read this monograph, written in simple and clear language with numerous examples.
The starting point for rethinking the thermodynamics of the low-temperature decomposition of hydrogen sulfide was the paper published in 2004 with the participation of Parmon Doclady-2004 Read more>>. It is known that in all biological systems, the energy necessary for the life support of any organisms, from unicellular to higher beings, is stored in the chemical bonds of the molecules of nutrients used by biological organisms for development and reproduction. In all biological systems, the chemical potential energy released as a result of breaking certain chemical bonds is used to generate potential energy in the form of new chemical bonds of reaction products and a concentration gradient. Biological processes are characterized by a decrease in entropy, since the growth and development of organisms is accompanied by a complication of their organization and, from the point of view of classical thermodynamics, looks like a spontaneous decrease in entropy and an increase (accumulation) of free energy.
In accordance with the Gibbs equation, ΔG = ΔH – TΔS, the spontaneous flow of an irreversible chemical reaction is provided under the condition that in the exothermic process (the enthalpy of the reaction decreases, ΔH < 0), the entropy increases (ΔS > 0). However, if the entropy decreases as a result of an exothermic reaction (ΔH < 0) (ΔS < 0), then the Gibbs equation defines the boundaries of the spontaneous flow of the process. At the same time, if a certain amount of energy that entered the system as a result of an exothermic process is spent on increasing entropy (which is inevitable for any irreversible processes), then this part of the energy is lost to perform a useful action (for example, the formation of new chemical bonds in the reaction products), it is dissipated into the environment in the form of heat. Therefore, this part of the energy TΔS is called the bound energy. The remaining part of the energy can be used to perform a useful action, so the Gibbs energy is often called the free energy.
This situation is realized in the case of the decomposition of hydrogen sulfide on sulfide catalysts. Chemisorption and dissociation of hydrogen sulfide molecules are exothermic processes that occur with a decrease in entropy, which dissipates into the environment in the form of bound energy TΔS. The remaining Gibbs free energy is used to create new chemical bonds in the hydrogen and solid sulfur molecules. In general, a catalytic reaction is an exothermic process that occurs spontaneously at room temperature.
Similarly, a metal catalyst provides energy capture and storage from the exothermic processes of adsorption and dissociation of the initial hydrogen sulfide molecules into the atomic adsorbed state of hydrogen and sulfur. The stored energy is used for the chemical transformation of the adsorbed intermediates into the final products of the reaction-molecular hydrogen and diatomic triplet sulfur, followed by their desorption into the gas phase. This reaction is also an exothermic process that occurs spontaneously at room temperature MolecCatal-2020-497-111240-Startsev . Surprisingly, the cited review provides numerous indirect evidence for the possibility of catalytic decomposition of hydrogen sulfide at low temperature, but the term “catalysis” has never been used in these studies.
The driving force of the low-temperature catalytic decomposition of hydrogen sulfide is the formation of reaction products in the ground electronic state (singlet hydrogen, solid sulfur, or diatomic gaseous sulfur in the ground triplet state), i.e., having the lowest free energy. The energy source is the potential energy stored in the chemical bonds of the hydrogen sulfide molecule. The role of solid catalysts is to create conditions for the process of energy transfer from the exothermic stages of adsorption and dissociation of hydrogen sulfide molecules to the formation of new chemical bonds in the reaction products and their desorption into the gas phase.
This process is not possible in the gas phase.
Other materials on the low-temperature decomposition of hydrogen sulfide are published in our articles JSulfChem-2019-40-4-435-450-Startsev
Ready to answer all questions and comments.
