|A wall statue of American engineer Willard Gibbs (at Yale University), captioned as "discoverer and interpreter of the laws of chemical equilibrium", the central founder in the history of chemical thermodynamics.|
"The story of how chemical thermodynamics developed is a somewhat tangled one, since several investigators worked along different lines and quite independently of one another."
American chemistry historian William Jensen, citing Gilbert Lewis (1923), chapter one, summarizes that chemical thermodynamics was characterized by three distinct periods:
1. The establishment of the basic laws of thermodynamics (1842-1865).Jensen goes into more detail into each of these periods, in terms of the people and subjects involved. 
2. The application of these laws to the theory of chemical affinity and equilibrium (1873-1905).
3. The quantification of chemical thermodynamics via a fusion of theory with experimental data (1905-1923).
The 1788 variational principle of equilibrium of Joseph Lagrange, supposedly, was one of the formal apparatuses that led to the development of chemical thermodynamics. 
The preliminaries to the distinct science of chemical thermodynamics are the sciences of firstly affinity chemistry (1718-1882), launched with the making of Geoffroy's affinity table, as derived from Isaac Newton's famous Query 31, a subject that, according to chemistry historian and chemical thermodynamicist James Partington, is classified as marking the start or pre-history of the science of physical chemistry.
Secondly, the early subjects of "thermochemistry", examples of which are: the work of William Cullen (evaporative refrigeration, 1748), Joseph Black (latent heat, 1761), Richard Kirwan (specific fire, 1777), Joao Magellan (specific heat, 1780), Antoine Lavoisier and Pierre Laplace (reaction calorimetry, 1782), Person (heat capacity, date), Dulong-Petit law (Pierre Dulong and Alexis Petit, 1819).
Thirdly, was Hess' law (1840), that the heats of reaction in successive reactions must be added, formulated by Germain Hess.
The fourth and final transition stage into the newly forming subject of chemical thermodynamics was the short-lived thermal theory of affinity and the so-called "principle of maximum work", developed by Julius Thomsen (1854) and Marcellin Berthelot (1860s), which argued that heat release was the true driving force of chemical affinity and hence the true measure of chemical reactions. This theory, owing to shortfalls, such as not being able to explain endothermic reactions, was eventually replaced with the "thermodynamics theory of affinity".
All of this, in one way or another, was later integrated into the finalized version of what would become known as "chemical thermodynamics", a term that would not become commonplace until the early 1920s, finalizing with the work of Gilbert Lewis (1923) and Edward Guggenheim (1933) otherwise known as modern chemical thermodynamics.
|While German physicist Rudolf Clausius (1865) laid out the foundation of thermodynamics, it was German physical chemist August Horstmann (1869) who was the first to apply the newly formed "entropy" concept to chemical problems.|
In 1862, German physicist Rudolf Clausius, the central founder of thermodynamics, introduced his concept of "disgregation", a measure of the separation of the parts of a system from one another, a preliminary (or rather precursory) version of entropy, and suggested, supposedly, that the notion of disgregation would be particularly useful in chemistry as a measure of "affinity".  This, however, may be retrospect mis-interpretation (by chemistry historians Helge Kragh and Stephen Weininger), as nowhere (according to Google Book search) in Clausius' 1865 The Mechanical Theory of Heat is the word "affinity" to be found, nor is Clausius given mention in any of the various 19th century histories of chemical affinity. In any event, Clausius does (somewhere) outline how his new theory of energy and entropy of bodies applies to chemical reactions.
In 1865, German physical chemist August Horstmann began to study the work of Clausius, supposedly having been inspired by his disgregation ideas, for possible applications in the calculation of equilibriums in chemical systems.
In 1868, in order to ascertain molecular weights via a vapor density method, Horstmann began to investigate the effect of temperature on the equilibrium constant for a dissociation process, beginning with the Clausius-Clapeyron equation, but extending it to apply to a substance that is dissociating.
In 1869, Horstmann, in his paper “Vapor Pressure and Heated Evaporation of Ammonium Chloride”, was the first to apply entropy to chemical problems, and is often said to mark the start or beginnings, albeit not necessarily the foundations, in any sense of the matter, of the science of chemical thermodynamics.  In 1872-73, Horstmann applied the entropy principle to the problems of chemical dissociation, such as, supposedly, the dissociation of phosphorus pentachloride into phosphorus trichloride and chlorine: 
In October 1873, Horstmann famously announced the condition for chemical equilibrium to be that of maximum entropy.  That year he also gave the first, although incomplete, thermodynamic explanation of the Guldberg-Waage law of mass action (1864).  German chemist Fritz Haber, in 1908, gave an excellent summary of Horstmann’s contribution to science: 
“[While it was] Clausius [who first] called attention to the general applicability of the theory of heat to chemical reactions … we have Horstmann to thank for the fundamental advance from this incidental observation to a fruitful thermodynamic treatment of chemical problems.”(add)
Massieu | Characteristic functions
In 1869, French engineer Francois Massieu, building on Clausius, in his “On the Various Functions Characteristic of Fluids”, laid out the logic of “characteristic functions” (see: notation table), specifically his 1869 "characteristic function", symbol Ψ (psi), of a fluid body, or Massieu functions, as they have come to be known. Retrospectively, in 1876, Gibbs summarized Massieu’s contribution as follows: 
“Massieu has shown how all the properties of a fluid ‘which are considered in thermodynamics’ may be deduced from a single function, which he calls a characteristic function of the fluid considered; he introduces two different functions of this kind, vis, a function of the temperature and volume, which he denotes by Ψ, and a function of the temperature and pressure, which he denotes by Ψ’; in both cases he considers a constant quantity (one kilogram) of the fluid, which is regarded as invariable in composition.”
Though not necessarily a treatise on "chemical problems" the logic of characteristic functions of fluids was used by Gibbs, combined with the work of Clausius, to formulate chemical thermodynamics.
|American engineer and mathematical physicist Willard Gibbs (1876) and German physicist Hermann Helmholtz (1882) laid the foundation of chemical thermodynamics.|
The dominate thread of chemical thermodynamics is that attributed to the 1873-1878 work of American engineer Willard Gibbs, who extended the energy/entropy equations of Clausius to chemical phenomena, contained largely in his 700-equation "On the Equilibrium of Heterogeneous Substances".
The publication of German physicist Hermann Helmholtz' 1882 "On the Thermodynamics of Chemical Processes", in which he extended the earlier "available energy" ideas of Gibbs into that of "free energy" is often said to be the capstone of the finalized launching of chemical thermodynamics.
Gibbs | Planck | Duhem approach
Van't Hoff | Nernst approach
Van Laar | Nernst debate
Ostwald and the energeticists
|Physical chemists American Gilbert Lewis (1923) and Englishman Edward Guggenheim (1933) are considered as the founders of "modern chemical thermodynamics" for their textbook truncations of the dense earlier foundational work of American engineer and mathematical physicist Willard Gibbs (1976).|
Modern chemical thermodynamics | 1933-present
The founders of so-called "modern chemical thermodynamics" are American physical chemists Gilbert Lewis and Merle Randall, for their 1923 textbook Thermodynamics and the Free Energy of Chemical Substances, a simplified, polished, and applied version of the more robust work of Gibbs, and English physical chemist Edward Guggenheim, for his 1933 textbook Modern Thermodynamics by the Method of Willard Gibbs.  In 1986, American chemical engineer John Prausnitz, of the University of California, Berkeley, in his “The Two Sources of Chemical Thermodynamics” article, stated the following: 
“While the essential ideas of classical thermodynamics were established in the 1850’s and 60’s, application of these ideas to chemical phenomena came later, primarily by Gibbs in the 1870s. However, Gibbs’ work was not appreciated by chemists until the turn of the century and even then, extensive application of thermodynamics in chemistry did not occur until publication of a path-breaking textbook by Lewis and Randall in 1923.”
In 2000, American chemical engineers Bevan Ott and Juliana Boerio-Goates, in their Chemical Thermodynamics: Principles and Applications, summarize things as follows: 
“Lewis, Randall and Guggenheim must be considered as the founders of modern chemical thermodynamics because of the major contributions of these two books in unifying the applications of thermodynamics to chemistry.”
In 2012, Italian physical chemist Salvatore Califano, in his Pathways to Modern Chemical Physics, likewise, gives the following cogent synopsis of the formation of "modern chemical thermodynamics" or what seems to be modern chemical-physics as he terms it: 
“The mathematical formalism developed by Gibbs in several papers was utilized by Gilbert Lewis and Merle Randall in the United States and Edward Guggenheim in England for the evaluation of free energy and of a large number of chemical compounds. The book by Lewis and Randall Thermodynamics and the Free Energy of Chemical Substances of 1923 and that by Guggenheim, Modern Thermodynamics by the Methods of Willard Gibbs of 1933 are the fundamental classics of modern chemical-physics. Before the publication of these two textbooks, the most known text of thermodynamics, especially in Germany was the 1912 treatise Lehrbuch der Thermodhemie und Thermodynamik written by Otto Sackur, that, once translated into English in 1917 by the American naturalized Scotsman George Gibson, became the official textbook of thermodynamics in American universities until 1923, when it was replaced by that of Lewis and Randall.”
Of note, Merle Randall, here, was more of a note-taker in this picture, in the sense that Lewis, his mentor, would dictate, and Randall would record.
|German polymath Johann Goethe (1809), with his "affinity" based human chemical theory, and American electrochemical engineer Libb Thims (2007), with his "free energy" based equivalent, albeit modern human molecular formula based human chemical reaction theory, can be considered as the pioneers of the newly forming 21st century science of human chemical thermodynamics, an extension of modern chemical thermodynamics to social and economic phenomena.|
See main: History of human chemical thermodynamicsBuilding on the "modern chemical thermodynamics" Lewis-Guggenheim platform of, in 2007 the term "human chemical thermodynamics" was introduced by American electrochemical engineer Libb Thims as the subject of the chemical thermodynamic study of systems of reactive human molecules, and beginning in 2010 was lecturing on this subject to American engineering thermodynamics students, bioengineering thermodynamics students in 2010 to 2012, at University of Illinois at Chicago, and in 2013, to mechanical engineering thermodynamics students, at Northern Illinois University, specifically entitled "An Introduction to Human Chemical Thermodynamics" (see: 2013 lecture), explaining how German polymath Johann Goethe's 1809 human chemical theory of reactive "chemical affinities", symbol, A mediating human chemical reactions (see: theory), scales up through German physicist Hermann Helmholtz's 1882 thermodynamic theory of affinity proof that free energy is the true measure of "affinity", and through American physical chemist Gilbert Lewis' 1923 formulation of Gibbs free energy as the "driving force" for isothermal-isobaric chemical reactions (typical earth-bound reactions), in regards to prediction of reaction "spontaneity", through German-born American biochemist Fritz Lipmann’s 1941 theory of free energy coupling, as applied socially and economically (e.g. see: Robert Kenoun, 2006), in terms of human free energy theory, in respect to engineering applications (see: applied human thermodynamics) and basic principles.
A complete, full, and rigorous, modern book size history of chemical thermodynamics seems to be non-existent, possibly owing to the vastness and intricacy of the subject matter.
One of the first stand-alone articles on the history of the distinct field of "chemical thermodynamics" was American chemical engineer Linus Pauling’s 1970 article “History of Chemical Thermodynamics”, penned in honor of the centennial of the Sheffield Scientific School of Yale University (see: Gibbs school), home to American engineer Willard Gibbs, the so-called “founder of chemical thermodynamics”, as described by German physical chemist Wilhelm Ostwald, and the so-called Gibbsian school of thermodynamics. Pauling’s article, however, is terse, only mentioning (the work of Gibbs aside): Walther Nernst (on the third law) and William Giauque (on entropy calculations of crystalline substances at near absolute zero temperatures via the use of adiabatic demagnetization). 
Canadian physical chemistry historian Keith Laidler, as quoted above, has a fairly detailed twenty-page 1993 chapter section on the history of chemical thermodynamics. 
1. Laidler, Keith. (1993). The World of Physical Chemistry (§4.4: Chemical Thermodynamics, pgs. 107-26, 434). Oxford University Press.
2. Kragh, Helge and Weininger, Stephen J. (1996). “Sooner Science than Confusion: the Tortuous Entry of Entropy into Chemist” (abs), Historical Studies in the Physical and Biological Sciences, 27(1): 91-130.
3. Horstmann, August F. (1869). “Vapor Pressure and Heated Evaporation of Ammonium Chloride” (“Dampfspannung und Yerdampfungswärme des Salmiaks”), Ber., 2: 137-40.
4. (a) Horstmann, August F. (1872). “Article”, Ann. d. Chem. U. Pharm., 8. Suppl.-Bd., 112-13.
(b) Horstmann, August F. (1973). “Theory of Dissociation” (“Theorie der Dissociation”), Liebig’s Annalen der Chemie und Pharmacie, Bd. 170 (CLXX), 192-210.
5. Boerio-Goates, Juliana, and Ott, J., Bevan. (2000). Chemical Thermodynamics - Principles and Applications (pg. 1-2). New York: Elsevier Academic Press.
6. (a) Pauling, Linus. (1970). “History of Chemical Thermodynamics”, in The Centennial of the Sheffield Scientific School (pgs. 27-32) by Baitsell, George A. and Lawrence, Ernest O. Ayer Publishing.
(b) Sheffield scientific school – Wikipedia.
7. Califano, Salvatore. (2012). Pathways to Modern Chemical Physics (modern chemical-physics, pg. 15). Springer.
8. Haber, Fritz. (1908). Thermodynamics of Technical Gas Reactions (pg. 68). Longmans, Green, and Co.
9. Gibbs, Willard. (1876). "On the Equilibrium of Heterogeneous Substances" (Massieu, pgs. 86, 358),Transactions of the Connecticut Academy,III. pp. 108-248, Oct., 1875-May, 1876, and pp. 343-524, may, 1877-July, 1878.
10. (a) Prausnitz, John. (1986). “Abstraction and Reality: The Two Sources of Chemical Thermodynamics” (abs), Journal of Non-Equilibrium Thermodynamics, 11(2):49-66.
(b) John Prausnitz (faculty) – University of California, Berkeley.
11. Dmitriev, I.S. and Romanovskaya, T.B. (date). “Mathematics in Chemistry” (§9.16.3: Chemical Thermodynamics: a New Bridge Between Chemistry and Mathematics, pgs. 1263-), in: Companion Encyclopedia of the History and Philosophy of the Mathematical Sciences, Volume 2 (editor: I. Grattan-Guinness). JHU Press.
12. Jensen, William B. (2011). “The Quantification of 20th-Century Chemical Thermodynamics: a Tribute to Thermodynamics and the Free Energy of Chemical Substances” (pdf), Unpublished Lecture, Symposium, Mar 28.
● Kipnis, A. (1976). "The Heat Law in the History of Chemical Thermodynamics”, Voprosi Istorii Estestvoznaniya i Techniki, 4(53): 42-47.
● Lengyel, Sandor. (1989). “Chemical Kinetics and Thermodynamics: a History of Their Relationship” (abs), Computers and Mathematics with Applications, 17(1-3):443-55.
● Martinas, K., Ropoli, L., and Szegedi, P. (1990). “Thermodynamics Conference”, Eotvos University, Veszprem, Hungary, Jul 23-28; in: Thermodynamics: History and Philosophy – Facts, Trends, and Debates. World Scientific, 1991.
● Author. (2001). “Early Chemical Thermodynamics: Its Duality Embodied in Van’t Hoff and Gibbs” (pdf), in: Van’t Hoff and the Emergence of Chemical Thermodynamics, Willem J. Hornix and S.H.W.M Mannaerts, eds. Delft University Press.
● Alberty, Robert A. (2004). “A Short History of the Thermodynamics of Enzyme-Catalyzed Reactions” (Ѻ), The Journal of Biological Chemistry, 279:27831-36.