Allergy Relief at Scale: Plant Design for Diphenhydramine Hydrochloride; Navigating Laboratory Safety: The Dynamics of Compliance in Research

Introduction
This portfolio explores the complex relationship between technical systems and the social structures that shape their operation, with a focus on safety in chemical manufacturing. Engineering design is often presented as a purely technical endeavor, but its success depends on the people who interact with it and how they make decisions. This work examines that relationship through the lens of pharmaceutical manufacturing, where both process design and safety culture are critical. By combining a technical project, a plant design for diphenhydramine hydrochloride, with a sociotechnical study of compliance in research laboratories, this portfolio highlights how technical design alone is insufficient without consideration of the human systems the technology operates within. Design decisions, from equipment choice to process scheduling, are not only influenced by material constraints, but also by the expectations, behaviors, and institutional norms of the people who design and use them. Thus, a holistic approach to chemical engineering must account for both engineered safeguards and the social dynamics that determine compliance behaviors. Together, these projects demonstrate the value of integrating technical rigor with STS insight to build safer, more robust systems.

Capstone Project Summary
This report presents the design of a batch manufacturing plant for diphenhydramine hydrochloride (DPH·HCl), an antihistamine known by the brand name BENADRYL®. The proposed process eliminates the use of hazardous bromine, instead employing a novel solvent-free synthesis method utilizing concentrated hydrochloric acid, which enhances safety, sustainability, and atom efficiency. Located in Ponca City, Oklahoma, the facility operates 24/7 for 313 days annually, producing 457,320 kg of pharmaceutical-grade DPH·HCl per year with a minimum purity of 98%. The process consists of four major steps: reduction of benzophenone to benzhydrol, chlorination to form CDPM, nucleophilic substitution to synthesize DPH, and final purification. Each batch yields 250 kg of product and follows an optimized schedule with cleaning and holiday downtime incorporated. Equipment is designed using Aspen Plus v14 simulations and chemical engineering principles to ensure process efficiency and safety. Financial estimations predict an annual net profit of $638 million, assuming full product sales at current wholesale prices. This plant demonstrates the feasibility of scaling an innovative, safer synthesis route for DPH·HCl and contributes to more sustainable pharmaceutical manufacturing practices.

STS Research Paper Summary
This paper investigates the question: How do social groups influence safety practices in research laboratories? Despite the well-documented risks of laboratory hazards, many researchers prioritize productivity at the cost of safety. Such inconsistency in safety compliance, especially in academia, has had catastrophic consequences. This research aims to reveal how to encourage a culture of proactive safety behaviors rather than reactive compliance, which could align real-world laboratory practices with regulatory expectations. This study examines how many actors including researchers, regulatory agencies, principal investigators, and even laboratory equipment interact to shape safety culture. A deeper understanding of the social dynamics influencing safety can inform institutional policies, regulatory frameworks, and industry-academic collaborations to promote safer research environments. This research identified several socio-technical influences on safety compliance including peer pressure, power dynamics, cultural norms, psychological reactance, and human factors. These factors influence lab safety by reinforcing group norms and shaping whether individuals feel empowered to follow or challenge unsafe practices. Improving safety culture not only protects researchers but also ensures the sustainability and ethical integrity of scientific work. This work can serve as a foundation for future efforts to transform safety from an obligation into an integral part of research excellence.

Concluding Reflection
Working on these two projects simultaneously gave me a more holistic understanding of engineering. It challenged me to think critically about an assumption engineers often make about compliance: if we design something to be safe, it will be used safely. I learned to think more intentionally about how design decisions affect user behavior and how cultural and organizational factors shape the effectiveness of safety and engineering systems. This portfolio highlights how engineering solutions can only be as effective as the systems of people who operate them.
Together, these projects demonstrate the value of approaching engineering problems with both technical precision and social awareness, ultimately contributing to safer, more sustainable, and more resilient systems. This perspective encourages engineers to consider how their designs will interact with everyday human behavior. The result is a more comprehensive framework for understanding and addressing safety—one that bridges the gap between design intent and practical use.

School of Engineering and Applied Science

Bachelor of Science in Chemical Engineering

Technical Advisor: Eric Anderson

STS Advisor: Bryn Seabrook

Technical Team Members: Vanessa Campbell, Justin Kim, Abby Janiga, Yusra Babar