NASA CONTRACTOR NASA CR-1104 REPORT I Finai Summary , NATIONAL AERONAUTICS ,4ND SPACE ADMINISTRATION WASHINGTON, D. C. JULY 1968 NASA CR-1104 STUDY OF METHODS FOR CHEMICAL SYNTHESIS OF EDIBLE FATTY ACIDS AND LIPIDS Final Summary Edited by John W. Frankenfeld Distribution of this report is provided in the interest of information exchange. Responsibility for the contents resides in the author or organization that prepared it. Prepared under Contract No. NAS 2-3708 by ESSO RESEARCH AND ENGINEERING COMPANY Linden, N.J. for Ames Research Center NATIONAL AERONAUTICS AND SPACE ADMINISTRATION For sale by the Clearinghouse for Federal Scientific and Technical Information Springfield, Virginia 22151 - CFSTI price $3.00 PRECEDING PAGE BLANK NOT FILMED. I* The authors wish to express their appreciation for the assistance V PRECEDING PAGE BLANK NOT FILMED. CONTENTS Page LIST OF FIGURES ix LIST OF TABLES X SUMMARY 1 INTRODUCTION 2 Human Energy Requirements - Advantages of Fats 2 Statement of the Problem 3 Approach - Assumptions 4 TECHNICAL Di SCiiSSION 6 Historical - The German Process 6 REDUCTIVE POLYMERIZATION OF CARBON MONOXIDE 10 The Fischer-Tropsch Synthesis 10 Wax Cracking and Oxidative Dehydrogenation 19 The Ziegler Reaction 20 Telomerization of Ethylene and Acetylene 25 SYNTHESIS OF ETHnENE AND CONVERSION OF Cog TO CO 26 Ethylene y& Methane and Acetylene 26 Reduction of Carbon Dioxide to Carbon Monoxide 29 Conversion of Carbon Monoxide to Ethylene 31 CONVERSION OF HYDROCARBONS TO ACIDS 34 Oxidation of Paraffins 34 Oxidation of Olefins 34 Ozonolysis 35 The Oxo Reaction 35 Rearrangement of Epoxides 37 Conversion of Ziegler Intermediates to Acids 37 vii Page CONVERSION OF FATTY ACIDS TO GLYCERIDES 39 SYNTHESIS OF GLYCEROL 41 Glycerol Synthesis from CO and H2 41 Synthesis from Acetylene or Ethylene 41 Trimerization of Formaldehyde 42 b Hydrogenolysis of Carbohydrates 48 ENGINEERING DESIGN AND EVALUATION 53 NUTRITIONAL EVALUATION OF SYNTHETIC FATS 62 Y CONCLUSIONS 66 RECOMMENDATIONS FOR FURTHER RESEARCH AND DEVELOPMENT 67 REFERENCES 72 viii FIGURES Page 1 Summary of Germany Synthetic Fat Process 6 2-4 F-T Processes Yield Complex Mixtures 12 5 Effect of Temperature on Hydrocarbon Distribution (in the Fisc her - Tropsch Synthesis) 18 6 Effect of Temperature on Functional Group Distribution (in the Fischer-Tropsch Synthesis) 18 7 Selectivity as a Function of Temperature with Precipitated Iron Catalyst, 1H2 + 1CO Gas, Space Velocity 720 hr-1, and 12 atm. (in the Fischer-Tropsch Synthesis) 18 8 Alcohol and Olefin Content of Distillation Fractions in Figure 9 (in the Fischer-Tropsch Synthesis ) 18 9 Product Distribution from Typical Wax Cracking Run 19 10 Typical Distribution of 4-Olefins from Ethylene Buildup (Zie gler) 19 11 Distribution of Alkyl Residues of the Form R-(C2H4)p- on Aluminum in Growth Products from One Mole of R-A1 and n Moles of Ethylene 22 12 Continuous Process for Production of -Olefins via Ziegler Growth Reaction 24 13 Condensation of Formaldehyde under the Influence of Alkali (Pfeil and Ruckert) 43 14 Course of Reaction of Aqueous Formaldehyde with Alkaline Catalysts 43 15 Pb(OH)2 vs. Ca(OH)2 Catalysis; Both curves 4% HCHO Soln. 45 16 Effect of Pb(OH)2 Concentration on Yield of Lower Sugars and Rate of CH20 Disappearance 45 17 Effect of Increased Benzoylcarbinol Concentration of Yield of Lower Sugars and Rate of CH20 Disappearance 46 18 Phenacy l- ionexchange Re sins as Catalysts for the Formaldehyde Condensation. 47 19 Glyceride Synthesis via Ziegler Growth Reaction Schematic 54 20 Synthesis of Fat; Engineering Design 60 ix TABLES Page 1 Food Requirements and Waste Gas Control in Closed Environment 2 2 Energy Requirements for Various Activities during Space Flight 3 3 Boiling Range of Fatty Acids from T, German Paraffin Oxidation 7 4 Analytical Constants for German Synthetic Fatty Acids 7 C 5 Analysis of German Synthetic Fat 8 6 Acid Analysis of German Fat, Butter and Coconut Oil 8 7 General Summary of Fischer-Tropsch Processes 11 8 Effect of Operating Pressure on Activity and Selectivity in Fischer-Tropsch Synthesis 17 9 Composition of Reaction Products of Acetylene from Hydrocarbon Processes 28 10 Data from Peters Patent on Conversion of Carbon Monoxide to Ethylene 33 11 Hydrogenolysis of Carbohydrates with Various Catalysts 49 12. Electrical Power Requirements for Fat Production Ziegler Growth Method 55 13 Pump Data 55 14 Compressor Data 56 15 Control Breakdown 56 16 Distribution of Olefins and the Corresponding Acids from the Ziegler Growth Reaction 57 17 Material Balance for Fatty Glyceride Synthesis 59 X SUMMARY A survey and critical evaluation of existing methods for the synthesis of fatty acids and lipids from metabolic wastes under conditions of space travel has been completed. An eztensive literature search was conducted and the candidate cL processes were evaluated from the standpoints of chemical feasibility and nutri- tional value of the products. The only promising'route involved synthesis of ethylene from carbon monoxide, polymerization tog-olefins 2 the Ziegler growth 3 reaction, conversion to fatty acids by oxidative ozonolysis and combination with glycerol to form edible glycerides. A first approximation engineering design was made and some rough estimates of power requirements were drawn up. The system was found to be extremely complex and unreliable. Hence it is not recommended as a method for food preparation on board a space craft. Four methods for the synthesis of glycerol were discovered. The most promising are base catalyzed trimerization of formaldehyde followed by hydrogenation and hydrogenolysis of higher sugars which may be prepared by controlled polymerization of formaldehyde. The synthesis of glycerol is much less complicated than fatty acid production and hence is a recommended alternate. A series of recommendations for further research and development were drawn up. These are mostly in the area of engineering and nutrition. INTRODUCTION The support of life in space presents many and varied problems. Two of the most pressing of these are food supply and waste gas disposal. The magnitude of these combined problems is apparent from Table 1. Per Man/Day 3 Yr. Total for 10 Man Crew Food Req. 1.2 - 1.8 lbs. 12,000 - 19,500 lbs. c02 Output 2.5 lbs. 27,300 lbs. C02 Adsorbent 2.6 - 4.25 lbs. 28,500 - 46,500 lbs. Total 67,800 - 93,300 lbs. Table 1 - Food Requirements and in Closed Environment For missions of long duration, control of C02 combined with 02 regener- ation becomes a virtual necessity. A variety of methods for C02 reduction have been devised(’, 5y 93 lo). Under such conditions the major weight contribution to life support becomes stored food. In missions exceeding two years this may amount to 85% of the entire life support The intriguing possibility of controlling waste materials by converting them to foodstuffs is in the infant stage of development. Several schemes have been proposed including rowth of plants (including algae and 5-8y lo), Hydro enomonas bacteria(” 5-7), secondary systems involving growth of fish on algae?”) , and chemical synthesis of carboh~drates(~,7, , proteins(”’ 12) and various nonfat energy sources su h as glycerol(5, 7, 131, 1,3-b~tanediol(l~-~~) and 2,4-dimethylheptanoic acid( 15). The chemical processes have certain advantages over the biological systems. Potentially, at least, they are more efficient in the use of raw materials, energy and space and yield less inedible waste materials. A chemical process is inherently more reliable. More control may be exerted over reaction variables; chemicals are not susceptible to disease, mutation or virus attack. Finally, chemical systems make use of hydrogen, a by- product of oxygen recovery by water electrolysis. This permits maximum material and energy conservation. Only hydrogenomomas, of the proposed biological processes, makes use of hydrogen. In addition to the schemes already mentioned, the possibility remains of synthesizing edible fats, patterned after natural materials, from C02 or its reduction product,CO. This report is concerned with such a possibility. Human Energy Requirements - Advantages of Fats The energy requirements for various activities during a flight mission are given in Table 2(16). Based upon such analyses allowances of 2500(10) and 2 Energy Expenditure Total -Per- -Time -Rate formance Activity -hr . calories/min. calories Sleep 7 1.2 504 Quiet Sitting or Standing 12 1.5 1080 Instrumentation 2 1.8 216 I Complex Neuromuscular 1 Tasks 2 2.6 3 12 4 Moderate Work 1 7.0 42 0 Table 2 - Energy Requirements for Various Activities during Space Flight(l6). 2800(4) calories* per man-day have been suggested for space craft energy requireme ts. Fats, which provide 9.3 cal./g. VS. 4.1 Cal-/g. for carbohydrates and proteins, (177 are by far the most economical sources of energy. Even when allowance is made for the extra oxygen required for complete oxidation, fats possess a clear advantage from a weight standpoint. Weight per 1000 Calories (16) Substance Food (gm.) Oxygen (sm. 1 Total (gm.) Carbohydrate (Sucrose) 253 284 537 Fat (Tri-olein) 106 307 -413 Savings in weight for fat (1000 calories) 124 gin. In addition, fats are welcome addition to the diet both from the standpoint of taste and hunger satisfaction. Finally, the incorporation of at least small quantities of fatty acids in the diet may be essential(18y 19). There are, however, certain limitations to the amount of natural fats which may be consumed. An upper limit of 50% of total calories has been suggested(16). A more detailed discussion of fat requirements is given below. Statement of the Problem The purpose of this study was to survey and critically evaluate methods for the production of edible fats from metabolic wastes by chemical means under conditions of space travel. Five steps are involved in such a process.