This article is concerned with the problem of carbon dioxide-the origin, the concentration in the atmosphere and the circulation on land, in ocean and between air and ocean. The effect of the consumption of the fossil fuels by human beings on the concentration in the air is described.
The influence of CO2 concentration on photosynthetic CO2-fixation is briefly reviewed. CO2 concentration in the atmosphere greatly affects photosynthesis. Pathway of photosynthetic CO2-fixation in C3-plant differs in many respect from that of C4-plant. Differences in levels of CO2-compensation points between C3-plant and C4-plant are ascribed to the presence of photorespiration in C3-plant and it's absence in C4-plant. Activity of RuDP carboxylase/oxygenase, the key enzyme of photorespiration, is controlled by CO2 concentration. Therefore, the formation of intermediate compounds of glycolate pathway is also controlled by CO2 concentration. Levels of enzymes functioning in photosynthetic CO2-fixation pathways adapt to CO2 levels during the growth of plants.
Two kinds of microorganisms, microalgae as photolithotrophic one and hydrogenbacteria as chemolithotrophic one are presented as the possible producers of single cell protein by CO2 fixation. The history and the present state of mass-cultivation of algae are elucidated. Several essential points for the future low-cost production of SCP by microalgae are indicated and discussed. Possibility of SCP production by CO2 fixation in fermenters using algae with light or using hydrogenbacteria with hydrogen and oxygen as the energy sources are also discussed. In conclusion, semi-natural cultivation of certain alkalic and filamentous algae in tropical arid districts is emphasized as the possible low-cost production method of SCP by algae.
Regulation of photosynthesis and respiration by CO2 (HCO3-) is reviewed. Control mechanism of photosynthetic CO2-fixation is discussed through the kinetic parameters of ribulose-1, 5-bisphosphate carboxylase (oxygenase) and phosphoenolpyruvate carboxylase. Stimulation of photosynthetic oxygen evolution by HCO3- is also mentioned. Govindjee's current investigations have given much informations on this HCO3- effect and will provide a clue to the solution of oxygen evolution mechanism. Final attention is paid on the effects of CO2 (HCO3-) as the substrate or the effector of respiratory enzymes on many developmental processes of animals and plants.
Carbon dioxide is a final combustion product of organic compounds together with water and therefore it is a stable, unreactive compound. In natural the carbon dioxide is metabolized by plant producing various kinds of carbohydrates by the action of solar energy and at the same time oxygen molecule is driven off as the result of deoxygenation from carbon dioxide. In pure synthetic method it is very difficult to carry out efficiently this deoxygenation of carbon dioxide in the aim to produce carbon monooxide or carbenoid species. In this article the author wants to show from the literature some new chemical reactions of carbon dioxide, in which the carbon dioxide is cleavaged in its C-O- bond and further to show how are at present the chemical methods progressing about the deoxygenating of some oxygen-containing organic compounds.
The recent literature concerning the fixation of carbon dioxide with transition metal complexes is surveyed. Carbon dioxide forms adducts with various transition metal complexes and reacts with transition metal complexes having metal-carbon, hydrogen, oxygen and nitrogen bonds to give its insertion products into these bonds. Based on the information accumulated concerning the reactivity of CO2 with transition metal complexes, several feasible prospects utilizing carbon dioxide as one of the cheapest carbon resources are presented and critically discussed.
Radiation-induced carboxylation of deaerated aqueous solutions of alcohols, amines and acids with carbon dioxide or sodium carbonate, and radiolysis of the liquid carbon dioxide solution of several aliphatic and aromatic olefins, were mainly explained from the viewpoint of radiation chemistry.
There are many studies on the reaction and chemical property of carbon dioxide, and carbon dioxide is practically used in various fields. In this paper, the carboxylation of alkali phenoxides with carbon dioxide is reviewed and the chemical behavior of carbon dioxide in the reaction is discussed from the viewpoint of the use of carbon dioxide in industrial organic chemistry. The production of hydroxybenzoic acids from alkali phenoxides and carbon dioxide is one of some examples in which carbon dioxide is used as raw materials in industrial organic chemistry. A large portion of salicylic acid and p-hydroxybenzoic acid prepared by the process have been used for preparation of pharmaceuticals. Recently, bifunctional p-hydroxybenzoic acid was polymerized and the characteristic properties of the polymer have stimulated investigation of polymerization using p-hydroxybenzoic acid. The carboxylation of alkali phenoxides with carbon dioxide is carried out in a heterogeneous system which consists of the solid phenoxide and carbon dioxide under a pressure. The mechanism of the carboxylation of sodium and potassium phenoxides in the heterogeneous system and the chemical behavior of carbon dioxide in the system are reviewed. The improvements of the procedure and method of the carboxylation are also described. Since the remarkable solubility of alkali phenoxides in polar and aprotic solvents such as DMF, DMSO and HMPA was found, it has become feasible to undergo the carboxylation at a homogeneous system. The carboxylation of alkali phenoxides with carbon dioxide in the solutions undergoes at mild conditions. Furthermore, it is noteworthy that the predominant carboxylation at p-position of the phenoxide is observed even in the case that sodium phenoxide is used. The reaction of carbon dioxide and the alkali phenoxides in DMF is discussed in connection with an activation of carbon dioxide, and it is suggested that the remarkable feature of the carboxylation in the solution may be caused by the solvation of the alkali phenoxides with the solvent and the activation of carbon dioxide by the solvated alkali phenoxides. Alkali alkylcarbonates are regarded as reagents fixing carbon dioxide. The usefulness of the alkali alkylcarbonates in the carboxylation of alkali phenoxides is described. Furthermore, a convenient preparation method of the alkali alkylcarbonates from alcohol, alkali phenoxide and carbon dioxide is also described.
Syntheses of high polymers using carbon dioxide as a direct starting material have been discovered rather recently. The first example is the alternating copolymerization of carbon dioxide and epoxide to give aliphatic polycarbonate with high molecular weight. Effective catalyst system is the reaction mixture of diethylzinc and water or other compounds with two active hydrogens. The mode of ring opening of epoxide in the copolymerization has been studied intensively. Carbon dioxide-epoxide copolymer is thermally decomposed to give cyclic carbonate. The copolymer is rather readily hydrolyzed. N-phenylethyleneimine copolymerizes with carbon dioxide by acidic catalyst to give copolymer with urethane linkage. Ethyleneimine and propyleneimine give similar copolymers without using any catalyst. Vinyl ether copolymerizes with carbon dioxide to give copolymer having keto and ester groups. Butadiene also copolymerizes to give a rubbery, insoluble product. Copolymerization of cyclic phosphonate, acrylonitrile and carbon dioxide gives a sequential ternary copolymer. Condensation polymerization of carbon dioxide and aromatic diamine in the presence of diphenyl phosphite and pyridine gives polyurea with high molecular weight under mild conditions.
It is estimated in japan that about 500 million tons per year of carbon dioxide are being discharged in air, originating from automobiles and electric power stations as well as the hydrogen manufacturing plants. Carbon dioxide seems to me to be a promising carbon resources especially in the case of recent petroleum. crisis. This review deals with mainly the synthesis of gasoline or methanol starting from carbon monoxide via. carbon dioxide as well as the recovery of carbon dioxide from air. In addition, carbon dioxide seems to be connected with the origin of petroleum, as proposed by Gaucher (1968) and me (1968), so that it may be said that carbon dioxide chemistry is sure to be a promising field of pure and industrial chemistry in very near future.
Carbon dioxide has been widely used in society for a century or so. In the light of today need to save resources, it is an urgent task for us to reexamine this basic material from every possible standpoint. This paper, in which data on its physical and chemical characteristics in particular are compiled and handling methods for high pressure product are listed, has been prepared as referential data for technical people who are interested in carbon dioxide.